Why does my boiler leak when I turn it off?
When you switch on your heating pipes, fittings and radiators expand, and boiler pressure increases. So, a heating system might not leak when it’s off, but, a boiler could lose pressure when it’s on. The speed at which your boiler loses pressure determines how bad the new leak is.
Is it normal for a boiler to lose pressure?
99% of the time, a boiler losing pressure is a leak. It’s as simple as that. Unless the dial sits at 0 even when topped up (which could be a sign of a faulty pressure gauge), there’s a leak somewhere – even if you can’t see it in the boiler or overall heating system.
Is this a common problem with Worcester Bosch boilers?
This seems to be a common problem with Worcester Bosch boilers, with the amount of threads on this. I can only ever recall one valiant boiler having some problems. KIAB likes this. This seems to be a common problem with Worcester Bosch boilers, with the amount of threads on this. I can only ever recall one valiant boiler having some problems.
Why is the pressure dropping on my boiler?
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.
How to tell if you have an external filling loop?
Why is my boiler pressure red?
How to repressurize a boiler with a keyless filling loop?
Where is the key located on a boiler?
Can you top up boiler pressure without a heating engineer?
See 2 more
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Boiler losing pressure but no leaks from Rads and no drips from ...
We have recently renovated our house and had a new boiler/central heating system installed and the boiler is always losing pressure. Once the boiler has been pressurised to around 1.5 bar it will run perfectly fine while it's on but once the thermostat switches it off it will lose pressure.
Worcester Combi, no leaks but still losing pressure!?
Hi all Hoping that you can help, the Combi boiler is a Worcester Bosch CDi 42 Classic Green star that has started losing pressure. I had installed this boiler and pipe work and it had been fine for 7 years but recently needing to fill the water via the square tap every 3 - 4 days.
Boiler has no pressure - What do I do? - Mr Central Heating Blog
The lack of pressure is only a problem in pressurised systems and theses include System and Combination boilers which work on a sealed heating circuit. The pressure is created by an expansion vessel which has a diaphragm bladder inside it that contracts and expands with the increase and decrease of volume of water in the system.
What does it mean when a pressure relief valve is wet?
Check this for signs of dripping. If it is wet, this may mean that the pressure relief valve is faulty.
How to contact Worcester heating system?
Contact your local Worcester Accredited Installer. Call our Contact Centre on 0330 123 9339.
Why does my boiler keep losing pressure?
Basically, you have a leak. If there is apparently no leak in the home but the boiler pressure still keeps dropping, the culprit may be one of the boiler’s internal components.
What causes water to exit a water system?
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.
What is the PRV release pipe?
In the event of high pressure, excess water flows out of the boiler via the PRV and out of the building via the PRV release pipe. Don’t confuse this pipe with the condensate pipe, which is usually white, plastic, and connected to the drain or soil stack.
Why does water rust in central heating?
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.
What is a filling loop?
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.
Why is my boiler leaking?
If there are no visible leaks around the home, 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.
What happens if the diaphragm in the expansion vessel is broken?
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.
Is Your Boiler Losing Pressure But No Leak?
99% of the time, a boiler losing pressure is a leak. It’s as simple as that. Unless the dial sits at 0 even when topped up (which could be a sign of a faulty pressure gauge), there’s a leak somewhere – even if you can’t see it in the boiler or overall heating system.
How to release pressure on radiator?
You can release this system pressure by using a bleed key. To bleed radiators and towel rails, simply open the vent with the key slightly. You’ll start to hear air hissing out. Once the air stops water will start to drop out (or spray out if you’ve opened the vent too much). Close the vent off.
Why does my boiler lose pressure?
As we’ve already mentioned, leaks are the most common cause of a boiler losing pressure. If your system is particularly old, there’s a good chance soldered joints have become weak, which can cause a new leak. You only need a tiny leak for a system to start losing pressure.
What does it mean when your boiler is losing pressure?
So, if your boiler is losing pressure slowly (i.e. you can’t visibly see the dial going down, but pressure goes down overnight), the leak is small. If you can visibly see the pressure gauge going down, your boiler is losing pressure quickly, and the leak is big.
What happens to boiler pressure when you bleed radiators?
Remember if you are constantly removing air, the boiler pressure will drop each time you bleed the radiators.
What to do if boiler pressure is loose?
I f the connections are extremely loose, tightening them up (carefully) will usually solve the boiler pressure issue. If it doesn’t, the culprit in the system will need to be repaired or replaced.
Why is my boiler pressure gauge not reading?
There’s a chance the pressure gauge on the front of the boiler is not reading correctly. This is quite dangerous, especially if you are constantly topping up the pressure. It’s likely that this is the case if you top up the boiler pressure and nothing happens (or the pressure changes very little).
How many rads is normal?
6 rads is well within normal, so your current exp vessel should cope easily.
What does replacing an Ev boiler mean?
If the boiler is the junior I models and not the cdi one, then replacing the ev will mean de hanging the boiler.
What does it mean when water comes out of a discharge pipe?
IF the water came out yer discharge pipe with the pressure at its 'normal' range (1bar to say 2 bar), then that indicates that your safety release valve is leaking so will need to be replaced.
What is a safety release valve?
The safety release/discharge valve is a single object. It's essentially a spring-mounted rubber washer/tap which is pushed open at around 3 bar. Once the pressure drops, it should re-seal but it rarely seats as well as it did before and carries on dripping.
How much pressure should I use for a water pressure system?
The water side pressure is pretty flexible, although I personally don;t see any reason why it should be more than 1 bar. The lower it can work at the better as that simply leads to less stress on the system, and 1 bar is well over the min required (around 0.5 to 0.7bar).
Is Valliant easier to service than WB?
Valliant are easier to service the a WB, I have had Valliant boilers must 20 years plus in various houses, never had one go wrong, maybe just lucky.
Where is the red circle on a boiler?
The centre of the red circle is where the water has dripped from, leading to some rust and calcium deposit, though the origin of the drip seems to be further up inside the boiler. A small bowl has been in place to collect the leak .
Fraz1977
Hi. I have a Worcester Bosch 28i Junior boiler which is 4 years old. Last year, after the cold snap, when the outside temperature began to increase and the boiler wasn't on as much the pressure began to rise to 3 bar when boiler was operating and discharged water via outside prv overflow.
studips
you've covered all the bases, so you need to go back and find the leak in the pipework, you say every time it goes off, how long is this spell and how quickly does it drop?
45yearsagasman
8.5 PSI is only just over .5bar.To precharge the EV you must do it while the system is depressurised and there is an opening to atmosphere.Only then can you pump and measure the EV precharge.I would precharge to .8bar as a minimum,but follow MI's.
Fraz1977
It drops about half a bar of pressure every two hours or so when the boiler is not operating so yeah quite a lot of water appears to have been lost each time.
studips
copper expands when heated, it also moves. my money is on a leak under the floor.
Fraz1977
Mostly all of my system is plastic piping except the pipes directly to the boiler itself. Don't know if that affects your copper pipe expanding theory. I'm going under the floors to check for leaks tomorrow and will report back my findings.
Fraz1977
Well checked under floors today and no leaks at all from pipework or radiators. Pressurised expansion vessel again just to be sure it's not this but system still losing pressure, about half a bar every 2hrs.
How to tell if you have an external filling loop?
You'll be able to identify if you have an external filling loop, because there'll be two valves; one from the mains cold water and then a second val ve which is connected to the heating system. Attach the hose to each side of the valve and open the mains cold tap. Open the second tap which allows water in to the heating system.
Why is my boiler pressure red?
If you're experiencing issues with your boiler, then it could be down to your boiler pressure. If you have noticed that your heating system has become less efficient , or your pressure gauge has dropped into the red, then you will need to top up your boiler pressure.
How to repressurize a boiler with a keyless filling loop?
To repressurize the system with the keyless filling link simply pull down the blue lever. Once the pressure has increased to over one bar, release the lever.
Where is the key located on a boiler?
Locate the key this will usually be on a flap underneath the boiler or it may have been provided you as part of the installation
Can you top up boiler pressure without a heating engineer?
Topping up your boiler pressure is a simple fix and can be carried out without a heating engineer. First of all identify what sort of filling system you have and then follow the instructions, or watch our technical trainer show you how its done.