Problems with loss of pressure from ch system

[mooney3]

I had an Ideal Isar HE30 boiler fit nearly one year ago. About six weeks ago the system started to lose its pressure and would go to zero pressure over a 48 hour period. I topped up the system to 1.5 bar and bled all the rads. I checked all the rads and pipework in the loft for leaks with nothing to be seen.
The company who installed the boiler were called out twice. They have checked the boiler and visually checked the system pipework and rads for leaks. They are adamant the loss of pressure is in the system somewhere and not the fault of the boiler.
I have added a bottle of rad seal to the system to no avail.
The house is a 3 bed detached. The boiler is situated in the utility downstairs. There are no damp patches on any of the ceilings upstairs or downstairs and no damp patches on any of the walls. The dowbstairs is all concrete floors.
I think it is fair to assume that losing 1.5 bar of water pressure every 48 hours would give up some form of damp patch as it would be approx 5lts of water each time the pressure dropped to zero. This means over the last 6 weeks over 100lts of water has been lost from the system.
The pressure drops off whether the ch system is turned on or not. You can re-pressurise up to 1.5 bar, never have the heating on and 48 hours later the pressure will be zero.
I only have 3 weeks of the boiler warranty left and would appreciate any advice that would help me identify the fault.

Thanks

Paul

 

[JohnD]

are your downstairs pipes embedded in the concrete floors?

 

[tj351011]

hi paul
have you checked the pressure relief valve vent pipe should be piped through wall to outside?
tony e

 

[mooney3]

Hi,
thanks for the replies.
I am not sure where the downstairs pipes run, whether they run in the concrete or in the walls. I have only been in the house just over a year. Is there an easy way of telling where they run ?
The pressure relif valve isn't leaking, however there is a ver slow drip from the condensation outlet pipe.

Regards

Paul

 

[JohnD]

If you can't see the pipes they are probably laid in the concrete. that may be where your leak is.

How old is the house and the radiator pipes? Are they copper?

Lift all the floor coverings and (1) sniff for damp and look for damp patches. There will be an elbow joint underneath every radiator valve, if you are lucky it will be one of them. (2) feel for warm tracks where the pipes are and mark with chalk. It is possible to hire an infra-red camera which will show the warm puddle round a leak, but another way is to wet-mop the floor and watch how it dries faster above the heated part.

If there has been any drilling or nailing into the floor it may have punctured a pipe.

I am just a householder

 

[mooney3]

Hi,
The house is about 20 years old.
I take it from the reply you also think the problem lies with a leak in the system pipework. My downstairs has stone tiles in all rooms except the living room which has wood flooring and would have to be a last resort to lift it.
I have been informed that the boiler has an heat exchanger for the domestic hot water to run through. Could this be part of the problem. I have no idea how the insidfe of a boiler works as far as central heating and domestic hot water goes but I do understand pressurised systems.
Would one of these infra red cameras be expensive to hire and would they detect the leak without raising the wood floor or stone tiles.

Regards

Paul

 

[JohnD]

sorry, I've never hired one, but I have seen the resulting pictures.

 

[twgas]

If the drip from condensate pipe is constant - even when boiler is not firing - it could be your main h/ex.best bet is to isolate heating circuit (turn off flow and return valves) and see if pressure drops from boiler.

 

[mooney3]

Hi,
An update on continuous pressure loss problem.
Have had an Ideal boiler engineer out who checked all the necessary areas for leaks, h/ex, expansion vessel, prv, condensator pipe etc and concluded the boiler is in perfect working order. I have also just had the boiler serviced last week as part of 2 year warranty.
I have had the rads checked again and have been told the 10mm pipe which go into the wall will undoubtably not run in the concrete floor.
If this is true then all the pressure loss would be surely seen in the form of dampness.
I seem to be at a total loss as to where the problem lies and was wondering if any sort of pressure test can be done on the central heating system by disconnecting the inlet and outlet and putting in place some sort of machine that will pressurise the system, be it with air or water and be able to detect a loss of pressure.
Any new ideas welcome.

 

[gas4you]

Pressurise the boiler to around 1.5 Bar, then isolate it from the heating system via the flow & return isolating valves under the boiler.

If possible leave it for at least 24hrs (put up with the hardship).

If the pressure has not dropped it has proven the leak is NOT anywhere on the boiler. Open the isolating valves and if the pressure drops it is then proof that there is a leak on the syatem somewhere.

 

[mooney3]

Hi Dave,
thanks for the suggestion. I have tried this a couple of weeks ago but when using the domestic hot water the pressure in the boiler went up. It slowly came back down over time but with a wife and two kids it is very hard to stop them using the hot water meaning the pressure was always above what I set it at !!
I will try it again tonight and isloate before I go to bed. Then I can check in the morning before the hot water users get up.

Thanks

Paul

 

[mooney3]

OK,
System pressurised to 1.5 bar at 10.30pm last night and ch flow and return isolated at valves. No domestic hot water used. Pressure this morning at 6.00am is 0.75 bar. Does this mean the boiler is NG and if so why am I not seeing any leaks inside the boiler. I have removed the cover and can see no traces of dampness or drips. Are there any other checks to be done on the boiler. As said before, no drips from PRV, nothing from condensator outlet.
I have just reopened the ch flow and return valves and the pressure has gone up to 1.25 bar. Does this suggest that the system is holding its pressure and the boiler must be at fault.

Thanks

Paul

 

[gas4you]

On the face of it, it does appear to be the boiler, unless it was air that has escaped from the AAV.

If not there has to be leak on the boiler somewhere.