Help! Pressure drop problems

[ArturStrom]

I now regret it bitterly, but for my sins I purchased a Ravenheat CSI85AT Condensing Combi boiler. The boiler itself is coming up to 2 years old and had been OK until the last few months.

Pressure now drops from the optimum level to 0 in about 24 hours, more if the heating is only on low. I have had several plumbers round, including one who was Ravenheat trained and none of them have conclusively found out what the problem is, so I'd like to ask a wider audience.

What has been tried so far is the following:-

Checked both the overflow pipes outside to make sure that the water is not being discharged through these. There is some water coming out of the plastic pipe, but nothing from the copper one.

I have checked all the rads and all the pipes which are accessible and found no leaks there. This has been done in sections, and under pressure, with no signs of leaks anywhere. The amount of water I am putting in, I would have seen something by now!

System was tested under pressure without having the heating on and the pressure did not drop at all.

Ravenheat's own engineers only cover warranty work, so I can't ask them to come out and throw whatever they need at the boiler to get the thing working again.

I would like to find out if we can use a leak sealer, but want to make sure that the one I go for is approved for use with Ravenheat.

To be fair to some of the guys who have looked at this, the said they didn't want to keep on replacing bits until it fixed the problem as this might cost several hundred pounds for all the various parts/visits etc. I now need to get this fixed asap, and get a certificate of test as we have sold this house and I won't sell it with a knackered boiler.

I'd be grateful for any assistance anyone could provide on here.

Thanks!

 

[corgiman]

what does the pressure guage read when the boiler is running?

 

[ArturStrom]

It goes up to about 1.5 usually, the wife has just shouted up that it is 1.2 at the moment and the heating is on.

Thing is, the pressure drops pretty rapidly, so even though I juiced it up this morning, it will be down to < .5 by tomorrow morning.

 

[corgiman]

Have you check for drips outside at all?

there should be a pipe (its usually bent back into the wall) on the nearest outside wall to where you boiler has been installed?

 

[ArturStrom]

There are two pipes coming out, a plastic one for condensation, and a copper one that is the emergency overflow (I think), I have checked the copper one on several occasions and tried the "stick a bit of kitchen towel in it" trick and it is always bone dry. I did suspect that the only place that amount of water could escape without really noticing it would be through the plastic pipe, and when I taped something to it to collect the water, there was some, but not nearly as much as I am having to put in to get the system pressurised again.

 

[chrishutt]

Do you have any pipework running under the ground floor where a leak would not be noticed? Also double check all the radiator valve spindles since these are often where leaks occur.

By the way, roughly what size (e.g. 20mm) is the condensate pipe on the outside and where does it discharge?

 

[noonespecial]

Plastic pipe is condensate drain and water will discharge from this pipe. This should be water that condenses out of the flue gases. Not sure with this boiler whether it is possible that a water leak from heat exchanger or pipework in boiler casing could find it's way to this condense drain - someone will know on this Forum.

Copper discharge pipe is from safety pressure relief valve - no water should discharge from this. If it does system pressure will drop. Tie a balloon on the end and leave it for a while. You will be able to see if there has been any discharge.

If both above are ok then leak is from system in property (unless you have a most unusual system arrangement).

Cold pressure test will not necessarily show upa joint / pipe leak. Thes will expand with heat and gaps can then occur.

Have you got copper heating pipework.

Check rad valve glands.

Could possibly be a leak from heating system into domestic hot water system but I would have though that is most unlikely.

A couple of weeks back there was a similar thread and a suggestion was a thermal imaging camera or detector or a moisture detector to pin point a leak.

 

[corgiman]

the thermal imaging cameras are sex on legs

used one recently and found the leak BANG

lovely, wish they didnt cost 4k or i would get one

 

[noonespecial]

lovely, wish they didnt cost 4k or i would get one

Yes would be a market for a low cost unit-wish I had the inclination to look into that

 

[corgiman]

that was the lowest cost option I could find, it was in the plumb centre mag this month,

Brilliant bit of kit it really is, my boss is tighter than a frogs arse and wont buy one

And am even more water tight than the aformention amphibians rectum so i aint getting one.

wanna go halfs

LMAO

 

[noonespecial]

And am even more water tight than the aformention amphibians rectum so i aint getting one.

wanna go halfs

LMAO

No I'll wait until you can get them free with a mobile phone

 

[ArturStrom]

Firstly, in answer to chrishutt, I only have a very small area where the pipes were sunk into a concrete floor, although I did not fill this in until about a week after testing/installation. I would still think I would have seen evidence of leakage though, as the floor has electric underfloor heating and is tiled. I would think that the grout would show is there were a significant leak.

The condensate pipe is about 25mm, and this just drips out onto a concrete pathway. I can rig something up to catch what comes out if you like.

And to noonespecial

Confirmed about the pipe from the safety pressure relief valve, I did this with a plastic bag as well as with kitchen paper, no discharge from there at all.

All the pipework is copper & the rads have been checked.

Thanks for you help guys, very much appreciated.

 

[corgiman]

you might not get a show on the floor as the leak may be very minor

sorry not much help am i. maybe an idea to hire a damp meter to see

 

[noonespecial]

The condensate pipe is about 25mm, and this just drips out onto a concrete pathway.

Who installed that? Incorrect and needs sorting.

OK so leak is into condense drain system (if that is possible and I don't know the answer to that-need feedback from someone who knows this boiler well) or into small section of floor screed or somewhere else where pipework is hidden. Could try a moisture detector in screed as you say this is only a small area.

 

[corgiman]

cor well spotted noone

did it wrong again dad