Boiler losing pressure

[Aaron Knight]

Hi,

I own a Valient ecoTec boiler combi boiler which is located in the loft.

I am losing water pressure daily but am at loss as to what is causing it.

During the day, when I pressurise my system to 1.5 bars, it runs for 8 hours before losing, any pressure.

In the evening, once I pressurise it, it runs for about 20 mins before it loses pressure.

I have no rads in the loft, there are no water marks on the ceiling of the ground floor so the system is not leaking on the first floor.

I have also isolated the flow / return on the ground floor so no leaks there.

All trv valves have been checked and no leaks.

A gas engineer states the boiler is fine and that I have a water leak. At the rate that I am losing pressure, the leak would have showed up by now.

I am at a loss as to what could be causing it.

I would welcome any advice.

Thanks

Aaron

 

[Deleted member 120897]

Sounds like an expansion related issue, should be easy enough for any competent person to sort, must be able to work on gas boilers though. Only other issue could be the prv passing, there will be a copper pipe under the boiler that may terminate outside, check if that has water present.

 

[John.g]

As above, what is the boiler pressure after heat up or max pressure you have observed.?

 

[Aaron Knight]

As above, what is the boiler pressure after heat up or max pressure you have observed.?

Hi, i set the pressure to 1.5 but as the system works, the pressure moves between 1.4 and 1.8.

There is no drain of on the prv (I put a bit of tissue at the end and it's dry)

 

[John.g]

Not a problem there, then.
When the boiler is off for 30/60 minutes switch it off (electrically) and break/remove the plastic condensate line and place it in a bucket/container and monitor it for a few hours for leakage.