Isolate the cold water cistern: how-to guide

Need to isolate the cold water cistern? Whether you need to repair or replace the ball valve, or carry out further work on the low pressure side of your plumbing system, this article will explain several different ways to carry out this simple task.

How to isolate the cold water cistern

Isolation valve/service valve

The cold water storage cistern (and the feed and expansion cistern) are fed from the rising main. Water byelaws require that supply pipe to the ball valve is fitted with an isolation valve or service valve.

Before isolating the cistern, take a look at the arrangement of the feed pipe, especially if the feed and expansion cistern is close to the cold water cistern. If the isolation valve is before a branch or a tee, it may actually isolate both cisterns.

Isolation or service valves are simple to operate, and are opened or closed using a flat-headed screwdriver. When the slot on the screw is in line with the pipe, the valve is open. Turning the screw a quarter turn so that the blade is perpendicular to the pipe will close the valve.

Alternatively, you may find the isolation valve in the form of a stopcock. This will have a brass handle; do not confuse it with a gate valve. Gate valves have red, wheel-shaped handles, and are installed on the cistern’s outlet pipes.

If there is no isolation valve on the supply pipe

If there isn’t a service valve on the supply pipe, another way to isolate the cistern is to turn off the mains stopcock. This is typically located under or near the kitchen sink. Bear in mind that turning off the mains stopcock will not only stop the cold water cistern from filling, it will shut off the water supply in the entire household.

Tie up the ball valve

If there is no isolation valve on the supply pipe, and it is impractical to switch off the mains, then another way of isolating the cold water cistern is to tie up the ball valve. This can be achieved by laying a baton across the cistern and tying the arm of the valve to it with string or garden twine. However, this method obviously cannot be used if the purpose of isolating the cistern is to repair or replace the ball valve.


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Outside tap

An outside tap or garden tap is a tap fitted to the outside of a building which delivers water for use outside of the property. Outside taps are designed to be easily connectable to hoses and provide a convenient water source for a pressure washer, or for the use of a hose to wash the car or water the garden. Having an outside tap also means there is no need to impede the use of other water outlets in the home – for example, by fitting a garden hose to the kitchen tap.

Outside tap overview

Outside taps are usually made out of brass. This helps to prevent them from corroding from their exposure to the elements all year round.

A typical outside tap features a brass handle with a single spindle, and a male ¾ inch BSP thread for a 15 mm nozzle which allows for the connection of hoses. The nozzle usually features a simple layering to allow for the secure connection of a hose via a jubilee clip. However, this nozzle can be replaced with nozzles which are designed to fit directly into Hoselock-type hose connectors.

Outside tap plumbing

As for the supply side, a typical outside tap usually has a male ¾ inch BSP thread at the rear. This usually connects to a 90 degree tap connector which may also feature the backing plate for securing the tap to the wall. The tap connected is then connected to the supply pipe via a solder or compression fitting.

Alternatively, the backing plate and tap connector may have their own integrated length of copper pipe for running through the wall, ranging from 350 – 400 mm. This is commonly found on outdoor tap kits and can be trimmed to the desired length with some pipe cutters.

Outside taps should always be supplied by the mains and never from a cold water storage cistern, as a storage cistern would not offer satisfactory pressure.

There are several possible ways to connect an outside tap to the mains, such as teeing off from a property’s underground service pipe. However, the most common configuration is that the tap is fitted on the external wall of a kitchen or downstairs toilet, and the supply for it is tee’d off from the nearby pipework inside that room.

To prevent the contamination of the mains via the possible back flow of e.g. dirty water in a hose, water regulations require that the supply pipe is fitted with a double check valve. However, many outdoor taps available on the market at the moment come with their own integrated double check valve.

An outdoor tap must also be fitted with an isolation valve. This will allow for servicing or repairs to carried out without having to turn off the entire water supply to a property. In periods of freezing weather, an outdoor tap should always be isolated and the tap itself left open. This will prevent any water in the pipework from freezing and then bursting the pipe when it thaws.

Outdoor tap kits and fittings

While individual taps are available from most DIY stores and plumbing merchants, it is also possible to buy outdoor tap kits. These come with everything necessary for installing an outdoor tap in accordance with water byelaws.

An outdoor tap kit typically consists of:

  • The tap itself
  • The wall mounting. Depending on the kit, this may be in the form of an elbow tap connector, or it may be integrated with a length of pipe that runs through the wall.
  • A braided hose connector. This is used to connect the tap to the tee point on the mains inside the property.
  • An isolation valve/service valve
  • A double check valve. This is necessary if the outdoor tap does not have its own integrated check valve.
  • Screws and wall plugs

Some outdoor tap kits may also come with a spool of PTFE tap. This will ensure a watertight fitting on compression joints.

It is also possible to buy small thermal insulation jackets or “cosies”. These can be slipped over an outside tap and tied in place to prevent the tap from freezing in the winter.

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Frozen condensate pipe: how to fix

No heating or hot water? If your boiler’s suddenly stopped working during a snap of frosty weather, there’s a good chance you’ve got a frozen condensate pipe. This common problem is ironically the last thing you need during the winter months! Fortunately, there are a couple of easy solutions to get your boiler up and running again.

What exactly is the condensate pipe?

The condensate pipe is a plastic pipe which allows a condensing boiler to discharge waste water from the condensing process into the sewer.

During the combustion process inside the boiler, water vapour is produced. Instead of expelling this hot vapour out of the flue, condensing boilers draw out so much heat from it, that it cools down and condenses into a liquid. This liquid – moderately acidic water, is then expelled from the boiler via the condensate pipe.

While in some households the condensate pipe may discharge into the trap of a sink, it may run independently through the wall and into a drain. It may also connect directly to the soil stack. Residual water in the pipe during the winter may freeze, resulting in a frozen condensate pipe. The boiler’s sensors will detect that the condensate pipe is blocked, and trigger a fault code, preventing the boiler from operating.

How to unfreeze/thaw the condensate pipe

  1. Do not cut the condensate pipe. The condensate pipe is generally considered to be part of the flue of a boiler, and consequently, any work on it may only legally be carried out by a Gas Safe-registered engineer.
  2. Identify where the pipe may have frozen. Horizontal lengths of pipe with little to no fall are a likely suspect – they allow the water in the pipe to settle.
  3. Prepare some hot water. You will probably have to use your kettle or the microwave for this. Do not use boiling water.
  4. Using a suitable container such as a jug or a watering can, pour hot water over the pipe where you think it has frozen. Pipe elbows and horizontal pieces of pipe are good areas to start with. Alternatively, you can use a hot water bottle. Place it over the pipe and leave it for a few minutes.

If ice in the condensate pipe was indeed the culprit, it should melt away and any water which was behind it should flow away too. After resetting the boiler or clearing any fault codes, the boiler should now operate normally.


You can prevent a frozen condensate pipe in future by insulating the pipe with lagging. The lagging must be waterproof, as otherwise it will soak up water like a sponge and give the pipe a nice ice blanket, which will only make the problem worse.

Other ways to prevent a frozen condensate pipe include rerouting the pipe to give it the appropriate level of fall or rerouting it through the house so that is less likely to freeze. Alternatively, external runs of pipe can be widened from 22 mm to 32 mm. For these modifications, you should consult a Gas Safe-registered engineer.

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Direct & Indirect plumbing systems: what’s the difference?

There are many different types of plumbing system to be found in UK households. Each system comes with its own set of advantages and disadvantages. In this article, we’ll discuss the difference between direct and indirect plumbing systems, and what those differences mean.

Direct & Indirect plumbing systems explained

The fundamental difference difference between direct and indirect plumbing systems relates to how cold water is distributed throughout the home.

In an indirect system, the mains enters the property and branches off to supply the cold kitchen tap. It then rises up to the loft to feed the cold water storage cistern. The cold cistern supplies cold water to everywhere else in the household, such as the cold bathroom taps, and the hot water cylinder.

In a direct system, all of the cold outlets are supplied by the mains. The cold water storage cistern supplies only the hot water cylinder. Alternatively, there may not even be a cold water storage cistern, if the property has a combi boiler or an unvented hot water cylinder. Both of these appliances are also fed directly from the mains.

Advantages and disadvantages

As one would expect, each of these systems comes with its own set of advantages and disadvantages. The main advantage of an indirect system is that even in the event of an interruption to the mains, the household will still have a reserve of water. Residents will still be able to flush the toilet for a limited period of time, for example. Indirect systems also operate at a lower pressure than mains water. Consequently, they are much quieter, and less susceptible to water hammer and wear and tear.

The main disadvantage of indirect systems is the risk of stagnation and contamination that comes with keeping a large quantity of water open to the atmosphere. While current water regulations require cisterns to be fitted with a set of components to ensure the water remains potable, i.e. drinkable, the concept of brushing one’s teeth in water which has come from a tank in the loft may not be very appealing.

This rings particularly true in the past, when the approach to the quality of water in the cistern was much more relaxed, and it was not uncommon to find drowned insects, rodents, and even birds at the bottom of a cistern. Indirect systems are ultimately why people in British homes are usually advised not to drink from the bathroom taps. On the other hand, a household with a direct system will offer drinking water from every cold tap in the property.

The other main advantage of direct systems is that their higher pressure means much greater flow rates

The other disadvantage of indirect systems is that they require space in the loft for a bulky water tank. Long, narrow “coffin” tanks can be fitted, but in the case of a loft conversion, a change of plumbing system may be needed.

Hot water cylinders

So there you have it – the difference between direct and indirect plumbing systems explained. Note that direct and indirect may also refer to types of hot water cylinder. In this context, direct and indirect refers not to how the cylinder is supplied, but how the water is heated. For more information, check the hot water cylinder page.

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Expansion pipe

The expansion pipe or vent pipe is a pipe associated with a cold water storage cistern or a feed and expansion cistern. Its purpose is to accommodate the expansion of water when it is heated, and to allow any excess water to vent harmlessly into the cistern. It also serves as an escape route for any air bubbles or gases which have formed.

Expansion pipe – cold water storage cistern

On a hot water cylinder, the hot outlet at the top of the cylinder is tee’d off. One pipe from this tee takes delivers hot water to all of the outlets in the home. The other rises up to the loft, up above the cold water storage cistern and bends down into it, without touching the water. On a cold water storage cistern fitted with a Byelaw 30 or Byelaw 60 kit, the lid of the cistern should contain a rubber grommet in order to admit the expansion pipe.

Air bubbles which naturally form inside the hot water cylinder when the water is heated can rise up and out of the cylinder, and up and out of the plumbing system through the expansion pipe. This prevents the formation of air in the system, which may lead to an airlock.

The expansion pipe on a cold water storage cistern is usually a length of 22 mm copper pipe. It should never be fitted with any valves, as this would open the possibility for hot water to be contained without anywhere for it go when it expands. This could be dangerous.

The expansion pipe should also never dip into the water in the cistern. This would create a gravity circuit between the hot water cylinder and the cold water storage cistern. Since hot water is less dense than cold water, hot water in the cylinder would flow up through the expansion pipe and into the cold cistern. The water would circulate in this way until the entire contents of the cold cistern has been replenished with hot water from the hot cylinder.

Expansion pipe – feed and expansion tank

On the feed and expansion cistern for the central heating, the vent pipe is a 22 mm copper pipe which rises above the cistern and bends down into it. The top of the bend should be at least 40 cm (15.75 inches) higher than the surface of the water in the cistern. This helps to ensure that water isn’t inadvertently pumped into the cistern when the boiler is on. This problem is known as pumping over, and will enrich the water in the cistern with oxygen. If left untreated, the oxygen-rich water will damage the system by promoting internal corrosion.

In order to prevent pumping over, the vent pipe should originate on the flow from the boiler behind the pump.

In the event of negative pressure in the vent pipe, air may get sucked into the system. This problem may occur when the feed pipe and vent pipe originate too far apart from each other on the system.

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Turn off the hot water: how-to guide

Need to turn off the hot water? Whether you have a hot water cylinder or a combi boiler, this is normally a very straightforward task. In this article, we’ll discuss how to turn off the hot water in your home.

How to turn off the hot water

The first step for this task is to understand how your hot water system works. Here’s a brief list of the most common configurations:

  • Combi boiler. This is the most common arrangement in UK households. With a combi boiler, there are no cisterns in the loft. Water for both the hot taps and the radiators comes directly from the mains.
  • Hot water cylinder with a cold water storage cistern. This is a very common arrangement. The cylinder is supplied with water from a cold water storage cistern in the loft. The cistern also accommodates for the expansion of the water when it is heated. This type of configuration is known as an open vented cylinder. On some hot water cylinders, the cold storage cistern may not actually be in the loft, and is instead an integral part of the cylinder. Such cylinders are known as Fortic cylinders.
  • Hot water cylinder without a cold water storage cistern. This is becoming more common in UK homes since they were permitted by the water regulations in the mid eighties. An unvented cylinder does not need a cistern in the loft because it is fed directly from the mains.

If you have a combi boiler

If you have a combi boiler, you can turn off the hot water by turning off the mains stopcock. You can usually find the mains stopcock in the vicinity of the kitchen sink. It may be in the cupboard under the sink, or it may be on an adjacent pipe. Turning off mains stopcock will also shut off the water to every outlet in your home.

If you have a hot water cylinder with a cold water storage cistern

Turn off the gate valve on the cold supply pipe to the cylinder. This valve should be easily recognisible as a valve with a red, wheel-shaped handle on a pipe that runs from the ceiling of the airing cupboard to the bottom of the cylinder.

Hot water comes out of the top of the cylinder due to gravity acting on the cold water in the cistern in the loft. Thus, stopping the cold water going in at the bottom prevents the hot water from being pushed out at the top.

This obviously means that even if you turn off the cold supply, the hot water cylinder will still be full of water. This is a safety precaution which prevents the immersion heaters or the boiler from trying to heat an empty cylinder. If you need to drain the hot water cylinder, take a look at the how-to guide for this task.

If there is no gate valve on the supply pipe

Can’t find a gate valve on the supply pipe in the airing cupboard? It may be in the loft on the cold pipe coming from the cold storage cistern.

If there isn’t a gate valve at all between the storage cistern and the hot water cylinder, another solution is to insert a rubber tank bung into the outlet at the bottom of the cistern.

If you have a Fortic cylinder

On a Fortic cylinder, there probably won’t be a gate valve on the cold supply pipe, because the cold supply pipe is probably concealed under the cylinder’s foam insulation. If there is a gate valve on the hot outlet pipe, it’ll be on the pipe coming out of the very top of the hot water compartment. (Should there be two pipes lower than this in line with each other, then these are the flow and return from the boiler, which you can ignore.)

If you have a hot water cylinder without a cold water storage cistern

If you have a pressurised cylinder, you’ll need to turn off the stop valve or isolation valve on the cold feed pipe. You can turn off the mains stopcock if you can’t find this. As previously mentioned, the mains stopcock is usually located near the kitchen sink, perhaps in the cupboard underneath it. Note that closing the mains stopcock will also shut off the water to every tap and outlet in your home.

Getting the hot water back on should simply be a case of opening the valve which you closed. If you have to turn off the mains stopcock, don’t forget to fill up some saucepans with water so you can still make a cup of tea!

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Condensate pipe

The condensate pipe is a pipe through which a condensing boiler discharges waste water from the condensing process into the sewer. As metal pipework cannot be used, it is often easily identifiable as the only plastic pipe connected to the boiler.

Condensate pipe overview

Water vapour from the combustion process is channelled through the boiler (along with other gases from the combustion chamber) until so much heat is drawn out of it that it condenses back into water. (In a non-condensing boiler, this process is absent – the hot gases are simply expelled out of the flue and the heat is wasted.)

The condensate, i.e., the water produced from the condensation process, is collected in the condensate trap. Just like how the water in the U-bend of a sink stops bad smells from travelling up the sewer into the home, the condensate trap uses a portion of condensate water to prevent toxic fumes from being expelled into the sewer. A standard condensing boiler will produce 2-3 litres of condensate per hour of operation, although of course this figure may vary depending on the model and capacity of boiler. Per BS 6798, the provision must be made for this waste water to be discharged into either an internal soil stack or waste pipe, or into an external soil stack, gully, or soak-away.

In many boilers, the condensate trap contains a small siphon. Condensate is collected in the trap until it fills up to a level where the siphon is activated and the trap empties itself automatically. Condensate flows through the pipe in bursts of a few hundred millilitres at a time, which may be heard trickling through the pipe. The siphonic discharge of small amounts of water through the condensate pipe is preferable to a steady flow, as a constant drip is more liable to freeze. Plus, short bursts of warm condensate will thaw any ice that has started to form in the pipe.


The condensate pipe must be plastic – usually solvent-weld fittings – and at least 22 mm in diameter. Copper or steel pipework cannot be used. This is because, at a pH of 3-4, the condensate is slightly acidic, and metal-based piping would be more susceptible to corrosion.

Condensate pipes that are outside or run through an unheated outbuilding, such as a garage, must be insulated with waterproof lagging in order to prevent them from freezing and should not be longer than 3 metres. Where it is undesirable to insulate the pipe for aesthetic reasons, 32 mm external piping will greatly reduce the risk of freezing. The upsizing of 22 mm to 32 mm pipe should ideally be made within the property so that water cannot freeze in a 22 mm section that is outside or within a wall cavity.

The condensate pipe must have a fall of at least 1:100. This gradient is required in order to prevent waste water from other appliances connected to the sewer (such as a washing machine) inadvertently entering the boiler’s combustion chamber. The gradient should also prevent water from sitting in the pipe and possibly freezing.

The condensate pipe must also have as few bends as possible. This is in order to prevent the condensate from getting trapped in the pipe.


One of the most common condensate pipe problems is that the water freezes inside it, blocking the pipe. The boiler’s built-in sensors will detect that it cannot discharge the condensate, and will consequently prevent the boiler from lighting, leaving the household without heating or hot water. If a frozen condensate pipe is suspected, this can easily be remedied by pouring warm water on the exposed section of pipe, or by placing a hot water bottle on it.

Other obstructions in the condensate pipe may include sewage, which has travelled up the pipe due to a poorly configured waste water system in the building. In some very bad cases, the sewage may travel far back enough up the condensate pipe to overwhelm the boiler internally.

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Combi boiler pressure explained & how to fix it

The little pressure gauge on the front of your boiler may be small, but the information it tells you is the difference between your boiler working, or having no hot water or central heating. In this article, we’ll discuss exactly what combi boiler pressure means, and what can be done to fix it if your boiler has no pressure.

Combi boiler pressure explained

In order for a combi boiler to operate, the water in the central heating must be pressurised. While the exact amount of pressure required for a boiler may vary depending on model and manufacturer, most combi boiler systems need to be filled to a pressure of 1 to 1.5 bar when they are cold.

Water expands when it’s heated, and so the pressure rises when the boiler is on. Should the pressure get too high – 3 bar is usually the limit – the water will be discharged out of the system via the pressure release valve (PRV).

In a household with a combi boiler, there is no feed and expansion tank in the loft. Instead, the water inside the radiators is supplied directly from the mains. However, water regulations do not allow central heating systems to be directly connected to the mains permanently. That’s where the filling loop comes in. The filling loop is a small section of pipe on or near the boiler which provides a temporary connection to the mains. It may be a rigid pipe or a flexible one, like a shower hose. Opening up the valves on the filling loop allows you to top up your central heating system with water from the mains – which is normally at a pressure of 1 – 3 bar. Higher pressures may be reported.

How to fix low boiler pressure

Topping up the system with water in order to bring it to the correct pressure is a very easy task. Simply open the valves on the filling loop until the gauge displays the correct pressure. Be sure to close the filling loop swiftly once you’ve reached it.

Why does my boiler have low pressure?

The answer to this question is very simple: water is escaping from the central heating system. To put it simply, you have a leak. In some cases, it may be somewhere around the house; in others, the culprit is one of the boiler’s components.

If you find that you’re having to top up the boiler pressure often, then you can’t afford not to find the source of the leak and get it fixed. That’s because the water in your central heating contains (or should contain) inhibitor, which protects your radiators and boiler from internal corrosion. By frequently adding oxygen-rich water to your central heating system, you’ll encourage it to rust from the inside out.

Finding the leak

Check all the visible joints on your central heating pipework, and check the connections to your radiators to make sure that they aren’t weeping. Make sure that the radiator bleed valves are fully closed – you will need a radiator key to do this. If the radiators have been recently bled, the system may need topping up from the filling loop.

The pressure release valve

If there are no visible leaks around the home, then the leak may have something to do with the boiler itself. A common culprit is the pressure release valve. A faulty PRV will allow water to exit the system when it shouldn’t.

In the event of high pressure, excess water is discharged through the PRV and out of the building via the PRV release pipe. This pipe can be identified outside. It should not be confused with the condensate pipe, which is usually white, plastic, and connected to the drain or soil stack.

Check the PRV release pipe. Is it dripping? Check the inside with a piece of tissue to see if it is wet. If the PRV is leaking very gradually, then the water may be evaporating before you can spot it. Look at the brickwork of the building to see if it has been wet over a continued period of time. Signs of water may include residual lime scale and a change in the colour of the bricks.

You can also test to see if the PRV is discharging water by hooking a plastic bag over the end of the pipe, or placing a container underneath it to catch the water. Never block the pipe, as this could be dangerous.

Common pressure release valve faults include:

  • The valve has become defective and will no longer remain closed.
  • The washer inside the valve has perished, usually due to age.
  • The valve has become jammed open due to debris in the system – most likely oxides from internal corrosion.
  • The valve has become jammed open due to a faulty expansion vessel.

If the PRV is faulty, it will need to be replaced. If the PRV has been jammed open due to corrosion debris, the system will need to be powerflushed.

Faulty expansion vessel

Another component which may cause your boiler to lose pressure is the expansion vessel. On a combi boiler, this component is usually fitted inside the boiler’s casing. Its purpose is to accommodate the expansion of the water when it’s heated.

The expansion vessel consists of two internal compartments divided by a rubber diaphragm. One compartment contains water from the central heating; the other contains pressurised air. Air is much more easily compressible than water, and so when the water expands, the air is compressed.

If the air pressure inside the expansion vessel is too low, the system will have no way of accommodating the change in the water’s volume. Consequently, the water will discharge out of the system via the pressure release valve. Eventually, enough water will discharge from the system so that the boiler will report low pressure when cold, and won’t light.

The same problem can happen if the diaphragm in the expansion vessel is broken. The water will expand with nowhere to go, be discharged out of the PRV, and the boiler won’t have enough pressure to operate.

The expansion vessel is usually fitted with a Schrader valve. This is the kind of valve that’s found on car and bike tyres. A tyre pressure gauge can be used to check the pressure in the expansion vessel. If the pressure is too low (the optimum pressure is 1 bar or 15 psi), a foot pump or handheld pump can be used to add pressure. Water coming out of the Schrader valve is a good indication that the diaphragm inside the valve has a puncture. In this case, the expansion vessel will need to be replaced.

If it’s not the boiler…

If there is no evidence that the boiler and any of its components are faulty, then the leak is likely to be concealed, e.g., if pipes run under floorboards or within walls.


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16 Awesome Plumbing tips that can save you a fortune

While some aspects of plumbing can be tedious, there are some ways to make them a little bit more straightforward. There are also plumbing tips which may not only make a job easier, but potentially save your property from thousands of pounds worth of damage. Here’s a selection of useful plumbing tips we think are worth bearing in mind.

Plumbing tips

The most important of all plumbing tips…

Clockwise opens it, anti-clockwise closes it!


Use a magnet to check pipework for corrosion. Copper pipe is not magnetic, whereas any iron compounds that have formed inside a pipe will make the magnet stick.

The perfect pipe edge

When cutting a new piece of copper pipe with some pipecutters, cut a tiny piece off at the end. Instead of the flat, blunt edge, you’ll have a nice tapered edge – perfect for a compression fitting.

Save your copper scraps

…but don’t forget to save the piece you cut off! Take your old bits of copper to a scrap metal dealer – never throw it away! An old hot water cylinder may fetch anywhere up to £100.

PTFE threading

When using PTFE tape, always thread the tape in the opposite direction of the thread of screw. This will ensure that it stays in place and doesn’t unwrap when you do up the fitting.

Lead pipe smoothing

Got an old lead pipe you need to sand down? Heat up a stanley knife over a flame and cut it smooth – it’s much quicker and easier.

Immersion heater safety

Make sure your immersion heater thermostat is the new type, which cuts out when it fails. Older ones can fail in the on position, boiling the water in the hot water cylinder, and overwhelming the cold water storage cistern with boiling hot water. In such circumstances, an improperly supported cistern may split, scalding or even killing residents in bedrooms below.

Know where your stopcock is

In the event of a leak, you don’t want to be wasting time finding the stopcock while a leak is busy damaging your property. Take a moment to find it – it’s usually under or nearby the kitchen sink – and test that it works.

Know where your outside stopcock is

In the event that your inside stopcock is inaccessible, you can’t afford not to know where your external stopcock is. It’s usually in a small hatch in the pavement in front of your property. Most importantly, you will need a stopcock key in order to operate it – you can get a basic one from your local DIY store for less than a tenner. It’s absolutely worth it getting one: in the event of a burst water main behind the internal stopcock, if you can’t turn off the outside stopcock then you will simply have no way of turning off the water until the emergency plumber arrives.

Get a spare ball valve

While you’re in your DIY shop, pick up a spare ball valve – you can pick up a decent Part 2 valve for around a fiver, if that. Leave it in the loft, and in the event of a leaking overflow pipe, you should be able to fix the problem as soon as it occurs.

Put inhibitor in your central heating

You absolutely can’t afford not to inhibitor your central heating. Inhibitor is a chemical which stops oxidisation occurring – basically, it stops your radiators from rusting inside out. A bottle of radiator inhibitor costs around a tenner – the cost of replacing multiple radiators can cost hundreds or even thousands of pounds.

The power of vinegar against limescale

Vinegar is an effective descaler – use it to remove limescale stains in the bathroom or even for descaling the shower head. Make sure to use distilled white vinegar, as other types – malt or white wine – may leave stains.

Get your boiler serviced

Whether it’s a combi boiler, a system boiler, or a heat only boiler, get your boiler serviced, especially if you’re the one who paid for it to be installed. In addition to a standard one year warranty, many boilers come with an extended warranty that can last anywhere from 7 to 10 years as long as they have been installed by an accredited engineer. Missing out on an annual service could cost the boiler its warranty – and you a lot of money, if it breaks down later.

Protect your hot water cylinder when removing an immersion heater

When removing an immersion heater, leave as much water in the hot water cylinder as possible. Sometimes a lot of force is required to unscrew an immersion heater. By leaving a mass of water in the cylinder, this will help to prevent the cylinder from warping as you unscrew the heater from its boss.

Broken ball valve float? Here’s a temporary fix

Isolate the valve and unscrew the float from the float arm. Drain out the water inside, and put it in a freezer bag. Screw it back onto the arm of the valve and tie the bag in place. This will serve as a temporary fix before you get a replacement float.

Remember your lockshield turns

Whenever you have to close a lockshield valve on a radiator, e.g. for cleaning or replacing a radiator, make sure you remember how many times you had to turn the valve. The lockshield should be set to allow the right amount of hot water to pass through the radiator so that it heats up evenly. Remembering the number of turns will save you from having to balance the radiator.

So there you have it – 16 plumbing tips which may not only make your life easier but could save you a pretty penny in the long run. Be sure to bookmark this page as more will be added in future!

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Primatic cylinder

Primatic cylinder, alternatively a self-priming cylinderis a type of indirect hot water cylinder in which the water for the central heating is separated from the domestic hot water by an air lock inside the heat exchanger. This is in contrast to a standard indirect cylinder, in which the heat exchanger is typically a coil of copper pipe.

Primatic cylinders are supplied by the cold water storage cistern in the loft. Their design means that a separate feed and expansion tank is not necessary. However, they come with several disadvantages that make them inferior to standard indirect cylinders.

Primatic cylinder overview

In a primatic cylinder, the heat exchanger also facilitates the supply of water for the primary circuit, i.e. the central heating. When the cylinder is filled, water flows through the heat exchanger allowing water to pass into the primary circuit. As the cylinder fills, the shape of the heat exchanger traps air inside itself – imagine holding a bowl upside-down at the bottom of the kitchen sink, and turning on the taps. This is the priming of the cylinder – the formation of the bubble.

When the cylinder is full and the boiler is activated by the cylinder thermostat, hot water flows through the heat exchanger. Heat is transferred by the heat exchanger to the rest of the water in the cylinder, providing hot water for the taps in the home. An immersion heater will usually be fitted so that the household will still have hot water even in the event that the boiler isn’t working.

A pipe rising up from the heat exchanger and bending down in the shape of a sharp loop allows any air or gases which form in the primary circuit to discharge into the cylinder. The gases will then rise up and out of the hot water cylinder, and out of the expansion pipe in the loft.

Since both hot water cylinder and central heating system are supplied with water by the cold water storage cistern in the loft, there is no need for a separate feed and expansion tank and its associated pipework. The expansion of the water in the primary circuit when it’s heated by the boiler is also accommodated by the heat exchanger – the bubble is compressed and changes position.

If you want to know why you have a cold water storage cistern, a hot water cylinder, and a boiler, but no feed and expansion tank or expansion vessel, then the most likely explanation is that you have a primatic cylinder. It is also possible to buy primatic fortic cylinders, i.e. fortic cylinders with their own integrated cold water storage cistern. These remove the need for loft cisterns altogether, although they are not frequently encountered.


In terms of construction, a primatic cylinder is similar in many respects to a conventional indirect hot water cylinder. The main difference – the heat exchanger – is internal. The top of the cylinder is bell-shaped to prevent air locks, and the bottom of the cylinder will usually be concave to improve its structural integrity. The cylinder should be situated on a flat, stable, continuous wooden base – ideally ¾ inch plywood across three timber bearers. Air gaps between the timber bearers will permit the circulation of air under the cylinder, limiting the formation of condensation.


While primatic cylinders remove the need for a separate feed and expansion tank in the loft, they come with several significant disadvantages. The main disadvantage is that any loss of the air bubble will cause the domestic hot water for the taps and the bath to merge with the murky stale water inside the radiators. An obvious indication that the two bodies of water have merged will be brown-tinged water coming from the hot taps – hardly the ideal sort of water for doing the washing up. The only way to correct this problem is to drain the cylinder down and fill it up carefully, allowing the air bubble to form again and hoping that it stays in place.

The possibility for these two waters to merge also means that one cannot put any inhibitor chemicals inside the primary circuit in order to protect the system. As a result, the radiators and the boiler are much more liable to corrosion damage and blocking, which may prove expensive. Also, it is not possible to fit a shower pump on a system with a primatic cylinder, as this may cause the loss of the airlock and the merging of the two waters.

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