Boiler losing pressure

[C_Hat]

Hi, a bit of a long one but would appreciate any comments or advice on this.

Moved into a new house a few months ago, where the previous owners didn't take great care of their CHS. Came to bleed radiators a few weeks ago as a number of radiators were banging but the bleed values were all so stiff and replaced them with new ones. These now work and i can bleed the radiators so banging has stopped.

Downstairs living room radiator does not give out any heat at all. Theres a small amount of rust on the bottom of it and the radiator valve is looking very old connecting into the pipes. Changed bleed valve on this to bleed but that hasn't made much difference. Since doing this, I have noticed that when the CHS comes on, the boiler pressure drops over a couple of days to less than 1 bar. So i am topping up the system every other day pretty much which I wasn't doing before.

No obvious leaks in the system and I have checked each radiator. the external overflow pipe is dripping a small amount when the system comes on, especially when its really cold. I have put two and two together and perhaps got 5 in thinking that changing the valve on the downstairs radiator is impacting on the pressure though this may be coincidence but I cant see any other clear issues that have changed in the last week which is when the boiler pressure has been dropping.

Every time i bleed a radiator changed a valve I have topped up system straight after and all valves closed as far as I can see. Had boiler serviced a few months a go and no issues were found inside it.

Any thoughts would be appreciated!

C

 

[centralheatking]

Hi, a bit of a long one but would appreciate any comments or advice on this.

Moved into a new house a few months ago, where the previous owners didn't take great care of their CHS. Came to bleed radiators a few weeks ago as a number of radiators were banging but the bleed values were all so stiff and replaced them with new ones. These now work and i can bleed the radiators so banging has stopped.

Downstairs living room radiator does not give out any heat at all. Theres a small amount of rust on the bottom of it and the radiator valve is looking very old connecting into the pipes. Changed bleed valve on this to bleed but that hasn't made much difference. Since doing this, I have noticed that when the CHS comes on, the boiler pressure drops over a couple of days to less than 1 bar. So i am topping up the system every other day pretty much which I wasn't doing before.

No obvious leaks in the system and I have checked each radiator. the external overflow pipe is dripping a small amount when the system comes on, especially when its really cold. I have put two and two together and perhaps got 5 in thinking that changing the valve on the downstairs radiator is impacting on the pressure though this may be coincidence but I cant see any other clear issues that have changed in the last week which is when the boiler pressure has been dropping.

Every time i bleed a radiator changed a valve I have topped up system straight after and all valves closed as far as I can see. Had boiler serviced a few months a go and no issues were found inside it.

Any thoughts would be appreciated!

C

Ok C Hat ...what sort of boiler do you have 1. a combi that makes hot water straightaway or a
2. system one that has a cylinder or 3. do you have roof tanks Or just tell us the name model on the front of the one you have...it seems quite simple so far. But you might well need to get a GSR engineer out tomorrow if the simple ideas do not work
centralheatking

 

[C_Hat]

Ok C Hat ...what sort of boiler do you have 1. a combi that makes hot water straightaway or a
2. system one that has a cylinder or 3. do you have roof tanks Or just tell us the name model on the front of the one you have...it seems quite simple so far. But you might well need to get a 'Registered Professional Gas Engineer' engineer out tomorrow if the simple ideas do not work
centralheatking

Hi, yes sorry I missed that bit off!

Its a Valliant combi boiler

 

[bacon_sandwich]

"The external overflow" - If you mean the pressure relief valve then this could be your issue. The boiler will dump your central heating water if the pressure in the system rises too much or the valve is faulty.

 

[C_Hat]

"The external overflow" - If you mean the pressure relief valve then this could be your issue. The boiler will dump your central heating water if the pressure in the system rises too much or the valve is faulty.

Thanks for the reply. Yes, the PRV goes outside and has been dripping regularly for a while now. My understanding was that was supposed to happen when the pressure gets too high but I guess if it’s dripping when pressure is low to normal that means the valve is likely faulty

 

[bacon_sandwich]

The PRV should not be dripping unless your pressure is too high, usually around 2.5-3.5Bar, if when you see the dripping your boiler is running at 1 Bar, then the valve is passing and that's where your water is going. Its usually a low cost item , just get a local GSR guy to change it.