Finding a leak on a combi

[trevorbayliss]

I am trying to work out where my loss of pressure is coming from on my system.

I think it is in the boiler, so i have isolated the boiler and will see if the pressure drops over the night time.

Do you just leave it like that or do you need to have the boiler running in order to see if there is a pressure issue in the boiler ? Can the boiler be run if the flow and return is closed off ?

 

[CBW]

You can just leave it like that, and you can use hot water, but heating will not work.

 

[ianmcd]

Most boilers will give HW with the heating flow and return closed , but dont switch the heating on with them closed

 

[trevorbayliss]

I will do this again tonight, so the boiler can be isolated for 12h's. But its been off for 4h's this afternoon and it held pressure at 1.1 bar. When i opened the valves the pressure dropped to 1 bar.

I checked the condensate trap again and it has quite a bit of magnatite in the bottom. I only cleaned this out 3 months ago i think.

Cleaned my spirovent filter again and also got a fair bit of magnatite out again.

So my system is giving off a lot of magnatite after i did a clean for 10 days feb 2019. i added on 2 new rads in my extension and connected them up to my system so at this time i decided to do a long slow clean using the chemical for this. Just a standard cleaner you can leave running for days.

Anyway, ever since i did this i have created a lot more crap from the system and wonder if i have caused this issue with my boiler.

 

[ianmcd]

But its been off for 4h's this afternoon and it held pressure at 1.1 bar. When i opened the valves the pressure dropped to 1 bar.

Then the leak is on your system

I checked the condensate trap again and it has quite a bit of magnatite in the bottom. I

No it dosent you will not get magnetite in a condensate trap

 

[trevorbayliss]

Well i got a fair bit of black little bits in there. sure looked like magnatite.

Luckily i can isolate my extension piping so i am going to see if this is my area to worry about.

 

[CBW]

Well i got a fair bit of black little bits in there. sure looked like magnatite.

Usually deposits from main heat exchanger

 

[trevorbayliss]

Last night the boiler stayed at 1.2 bar. So it looks like i have an issue on my system.

I have 3 areas where i might have this leak:

1) main house rad system (prob installed in the late 80's in copper and no issues for 12 years while been here). Also no leaks in ceilings or any rads leaking.

2) UFH zone in kitchen. Installed 2008 and no issues before. All in 15mm one piece of continuous plastic pipe.

3) New extension feeds two new rads and i ran my plastic under the suspended floor i built. So the leak could be on one of the speed fit fittings down there. I can easily isolate these rads so have valved these off from the main system and will see if i loose any pressure over the next few days.

If it is these rads then i am going to have to damage my oak floor to get down there. Or i can tap into these 2 pipes from the storage cupboard and then run up instead of down and have the pipes running wall mounted in the utility and dropping down to the first rad. This will look ugly but it might be the best option. It wont look so bad feeding the next room as the rad is on the same wall and so i would drill through and have a bit of pipe work running under the rad in there.

Does anyone know if you can get cameras which could look under the floor ? I could feed it in an air vent possibly, but it is a telescopic one so nit sure if that would work ?

 

[HERTS P&D]

Yes, you can use a thermal camera to find leaks, I have one. Call around various plumbers and ask if they have a one.

Andy

 

[trevorbayliss]

Update on my leak:

I still have it and am thinking it is the boiler.

I have zoned off the UFH loop and i still get a pressure drop

I have zoned off the new extension and still get a drop

I can also zone off the attic extension and still get a drop.

So the leak is in the main house, but i dont see any water marks.

So i am thinking its the boiler.

This F22 fault (low pressure) only started after the boiler was serviced and at that time i was getting the F75 error which means the pressure sensor needed changing. This was done and the boiler serviced and expansion vessel pressured. So ever since then i get this low pressure issue.

Is it the case the only place to loose water is from the pressure relief valve ? If so it is confusing because i never see any water dripping from here.

 

[CBW]

the F75 error which means the pressure sensor needed changing.

most of the time, but not always.

Is it the case the only place to loose water is from the pressure relief valve ? If so it is confusing because i never see any water dripping from here.

No, other places leak as well.

 

[trevorbayliss]

Can you tell me where to find a leak or where the water is going ? There is no water in the boiler or under it.

This is a mystery and at the moment i cant get an engineer out. So all we do is top up every week.

 

[CBW]

It can be a drip inside the boiler that evaporates, or even on the pump air vent. You mentioned earlier in thread, that you isolated the boiler with no pressure drop. It seems to me that it’s on the system. Zoning off will not tell you much, as water will still be held in the pipes. Try taking the pressure to about 2.8 bar and check system then.

 

[trevorbayliss]

I did isolate the boiler but we couldnt leave it like that for long so really it got 1/2 day with no change. At the moment the boiler is dropping after 2 days of use and then by the end of the week it goes below 0.5. So you could say it is dropping by 0.1 per day.

The area which i initially thought was the issue is the extension. These can be isolated using gate valves in my utility cupboard. So the whole area can be turned off from the main boiler system. So are you saying this test cannot prove there is no leak here. When i isolate the area, i am not meaning i shut down those particular rads, but rather shut down the flow and return into that area.

 

[bernardgreen]

I have zoned off

Did you close both flow and return to the zones and are you certain that the valves were not letting by a small amount of liquid when closed.