new combi install issue - Ideal vogue 32

[scottb]

Some questions on a new install. I'll ask the quick questions first then give abit background for those with time:

1) Is it OK to make a short test loop of around 1 mtr between boiler central heating output and return to rule out system leaks

2) can TRVS cause pressure loss with no visible leaks

3) Is leak sealant ok to use in new combis - have read conflicting comments. If OK thinking of giving some Fernox F4 express a try.




Tried giving more detail but saying 'forbidden words' so some bullet points :

New Ideal Vogue 32 and TRVS installed around 3 weeks ago.
system losing pressure - Installer and Ideal suspect system leak
Leak test carried out ( thermal and gas trace ) - no leaks found and nothing visible.
Pressure is lost randomly - sometimes 90 minutes, other times over a day ( it ran for over 2 weeks after a magna filter cleaned and leak seal added but has started again )

Thanks

Scott

 

[Alpha man]

The only way to find out whether it's the boiler or system, is to isolate the flow and return for 24-48 hours and without using the boiler at all, then if the pressure drops - it's the boiler, and if the pressure doesn't drop on the gauge, - you've got a leak on your system somewhere!

 

[Scott_D]

What type of system did it replace?
Pressurised or open vent?

 

[scottb]

straight combi to combi swap. An old Halstead for the Ideal. Sorry if original post was abit vague, put a more indepth post in but forum refused it.

Alpha - ye the day after it was installed a few weeks back we isolated it overnight and the pressure did not drop. If we get a chance between inspections / head scratching we'll leave it off longer . Everything points to a system leak but that came back fine. ( the company were here a full 8 hours with various probes / meters checking it )

If there is a system leak why the variance in time for pressure loss, it can run a day fine then lose full system pressure every 2 hours or so then start working ok on next top-up. I can only assume theres a leak somewhere that keeps getting blocked/unblocked

so
The Ideal engineer powered the boiler off today and it lost 1bar of pressure in 30 mins. No leaks inside boiler or from condensate/overflow.

There were no pressure loss issues with the old boiler before fitting the new boiler and TRVS.

Leaning towards running a short loop whilst waiting to here back from installer.

Thanks

 

[stevetheplumber]

running a loop would involve removing the heat or the boiler will switch of on temperature almost imediately could even go to overheat and cut the pump of as well i suppose you could put a roll of 22mm poly in the bath and run cold water
but surely easier to put a pressure gauge on the circuit easy enough to put one in the end of a rad with a bush. then isolate the boiler over night see which gauge drops

 

[ambrosia]

TRVs wont cause pressure drop

some boilers will run on low pressure while other lockout to protect the pump, so there is a chance the new boiler may not be to blame, that said its the 1st place i'd look

when you check for leaks around rads and visible pipework dont rely on a visual check, run you hands over as much as you can

also have a gas safe engineer check the expansion vessel on the new boiler, if its knackered it will be putting extra strain on ecerything and forcing the water out.

the link you suggested between flow and return wont prove much, an easier way to do it, there are 2 isolation valves under the boiler which will isolate flow and return, with those closed youll still get hot water but it will seperate the boiler from the heating circuit

also if youve been losing loads of water dont forget the inhibitor will be diluted by now

 

[Nostrum]

Sounds odd. The only thing I could see that would cause an issue like this is heat. Perhaps somewhere only leaks when hot or cold, radiator/valve etc. depending on the room temperature, the leak could only be apparent at certain times.

Whatever the outcome, please let us know when you find it. I like the Vogue and would like to know of any problems if it is boiler related.

 

[Geyser]

Had a similar issue once. Turned out builder had disconnected rad and shoved trv underfloor, run beautifully all day when I was there but dropped overnight when air temp dropped below floor boards. Didnt make sense till I found it!

 

[Rabbitman]

As previously said fill boiler up to 2:5bar close the isolation valves and leave overnight, if pressure holds its not the boiler, if it drops it's the system

 

[scottb]

Thanks guys.

Yes we've done the boiler isolation a few times. Everything points to a system leak but the pro's found nothing ( non invasive ). For the last 2 days it has failed to hold its pressure longer than 2 hours day or night so if it is a leak hopefully it will be obvious now. Some Fernox F4 leak sealant was put in last night but its made no difference.

Ideal and our installer have given the boiler a once over so we are taking them at their word that its sound, so the downstairs floor is coming up for a crawl around ( no staining on ceilings )

Will update if anything discovered. Don't care if its a massive leak just want it found/sorted.

 

[goz666]

What Steve said, put a pressure gauge on rad end.

 

[ambrosia]

Whatever the outcome, please let us know when you find it. I like the Vogue and would like to know of any problems if it is boiler related.

fiver says he never comes back

 

[scottb]

Pay the man ambrosia!

A failed 15mm tee found under the sitting room floor was to blame, it pulled out by hand. Luckily the first exploration hole identified it close by so a secondary hole was made for ease of access.

Repaired today and pressure stable. Hopefully puts an end to the stressful last 3 weeks. The only casualty being a small section of flooring that was lifted.

Good service from Ideal turning up to inspect the boiler free of charge like they did.

Quite why the leak detection did not pick it up I'll never know. Old school digging 1 technology 0


Thanks very much for the advice.

 

[AWheating]

What leak detection equipment did they use?

 

[scottb]

Ultrasonic then a Gas trace.

He thought he heard something then when the gas trace came back fine ( zero drop from 2bar over 2 hours and nothing showing on the sniffer ) he suggested the boiler was at fault.

Still running fine today.