Loss of pressure and leak detection

[mo7]

Combi boiler losing pressure for a few months. Serviced yesterday and engineer said he thinks boiler is OK and there is a leak in the pipe which I should have investigated (by the original installer).

I then emailed the original installer - but I now noticed the pressure was set to 2 last night and it has not dropped in 24 hours. Is it possible anything on the service could have solved the pressure loss even inadvertently?

Secondly, if I do have to find the leak I very much favour non invasive investigation and I can see you can pay large sums to have thermal imaging etc to find leaks. I suspect mine is very small .Are these usually pretty good or not?

Am I best just using a leak detector and then getting original installers in or one of the do it all types that find and repair?

 

[Chalked]

Hi
Yes your service engineer may have done a couple of things to the boiler that might have solved your problem.
See how it goes over the next few days. Leave it a 2 bar for now.
Btw . The pressure when cold, wants to be between 1.2 & 1.5 bar. Depending on the heating size and boiler position, 2 bar is a little high.
You can reduce this by venting water through a radiator.

 

[jtsplumbing]

How long has this boiler been installed ? Some basic things that you can check,
Look outside to see if anything is dripping from the small pipe coming through wall where boiler is located, check all your radiator connections, just a small weep will cause pressure to drop

 

[Stigster]

It is possible that a service could have cured the problem if the pressure relief valve was not seating correctly. It may have been passing a little water because of some grit on the seal and he's tested that component which may have flushed out said grit and solved the problem.

That's one possible scenario.

 

[mo7]

Just had a look this morning and it has gone down slightly

Am I right in thinking that when the Central Heating is on it would make the leak morel ikely to happen as the pressure goes up or would 2 bar at cold be enough?

I think I will need to fork out for a proper inspection of my system

No water coming out of the copper pipe outside.

 

[mo7]

Additional query - how long would you allow you inspect a boiler to check for leaks and to check 8 radiators? The majority of my pipes are buried in walls/joists.

I may pay out for the initial inspection to confirm there definitely is a leak and then deal with the leak properly.

 

[jtsplumbing]

Just double check the pipe outside, tie a plastic bag or something around it use boiler as normal for a day then check bag

 

[Stigster]

Just double check the pipe outside, tie a plastic bag or something around it use boiler as normal for a day then check bag

Good idea. I use the finger cut off a rubber glove and a rubber band to hold it on.

 

[mo7]

Good idea actually. will try tonight.

what i dont get is why the loss of pressure is very inconsistent in speed.

 

[mo7]

Last night, as advised by Worcester Bosch, I filled up pressure to 2 and closed off the feed/return. This morning it had gone down - a little but definite movement.

I will monitor until tomorrow night.

If the problem is within the boiler WB will fix it for free so I hope it is.

Should I fill it up and then monitor the pressure relief pipe outside? If that has water in it after a day would that be conclusive that there is something wrong with the boiler?

Also as I am not using the hot taps whilst the boiler is on would that affect the rate at which pressure is lost? (i.e if I was using the hot taps with the problem in the boiler would it cause quicker loss as the boiler is in use?) - I dont intend to use the boielr whilst feed/return is off.

 

[oz-plumber]

Are you sure you have a leak?

What does the system pressure drop to?
Do you realise that the pressure will increase and decrease due to the temperature of the water in the heating system.
Does the pressure gauge drop to almost zero or the boiler stop working due to the pressure switch cutting out?

 

[mo7]

it did cut out to 0 once which is how i knew there was a problem but i dont let it drop that far anymore

I THINK it was worse over winter when the CH was on a lot more - it has pretty much been off since say Feb so it feels like its a lot slower.

 

[jtsplumbing]

You say Worcester will fix it for free ? is your boiler still under warranty ?

 

[mo7]

yea, installed may 2016.