Boiler pressure loss through condensate pipe?

[gtg]

Hi all

I'm looking for some advice with a pressure loss issue that has been driving me mad for a while! It's on my vaillant 637 ecotec boiler, which is losing about 0.5-0.7 bar of pressure per day at present.

Just to be clear - I am not a professional so will not be attempting to do any work on the system myself. I'm just trying to understand what might be wrong.

There are no obvious leaks on rads, and the PRV discharge pipe is bone dry. I think that leaves leaking pipe under a floor, or cracked heat exchanger as the chief suspects.

Before I start ripping floors up to search for a leak, I noticed earlier today that the water coming from the plastic condensate pipe is rusty/orangey brown. Does this sound like a cracked heat exchanger causing pressure loss, or is it normal for the water to be this colour?

Are there any simple tests to confirm whether this is the cause of the leak?

Let me know if any more info or pics would help.

Thanks all for reading

 

[ianmcd]

yes a simple test, you should be able to disconnect the condensate hose where it comes out of the boiler, turn the pressure up to about 2 Bar and turn the boiler completely off, put the condensate hose into some kind of container and see if it gets water in when turned off, if it does new heat exchanger time

 

[gtg]

Brilliant, thank you Ian. I'll give that a go tomorrow.
Just out of interest, does the corrosion in the water sound unusual?

 

[ianmcd]

Brilliant, thank you Ian. I'll give that a go tomorrow.
Just out of interest, does the corrosion in the water sound unusual?

could be a few things but bleed a little water from a radiator and see if its the same colour, if it is could be a pinholed heat exchanger, wont be the heat exchanger discolouring it, that is made from Stainless steel

 

[gtg]

I switched the boiler off this morning and increased pressure to around 2 bar. Put a bucket under the condensate pipe and saw this about 4 hours later. I checked after an hour and there were just a few drops so it’s definitely something that was continuing while the boiler was off.

 

[ianmcd]

Yep new heat exchanger time, your best bet would be a Vaillant fixed price repair, it is around the £300 mark but includes all labour and parts and a warranty, they will change anything your boiler needs so the engineer keeps his/hers bonus, the heat exchanger alone will be near that

 

[muggles]

Yep new heat exchanger time, your best bet would be a Vaillant fixed price repair, it is around the £300 mark but includes all labour and parts and a warranty, they will change anything your boiler needs so the engineer keeps his/hers bonus, the heat exchanger alone will be near that

Either that or they'll declare it Beyond Economic Repair and stiff you for £90 for the privilege, which is what they did to one of my customers a few weeks ago

 

[ianmcd]

Either that or they'll declare it Beyond Economic Repair and stiff you for £90 for the privilege, which is what they did to one of my customers a few weeks ago

Just call them and ask, sorry to hear that @muggles has had that experience, I never have , but I respect him so best you check it out, as said I have never had that problem

 

[muggles]

To be fair it was a Glow-worm rather than a Vaillant, but it's still Group Service of course, and the same heat exchangers. I wasn't there but my customer said the engineer was very abrupt and seemed like he didn't want to do the job as soon as he walked in the door. Maybe just a bad egg rather than an indication of the company as a whole

 

[ianmcd]

To be fair it was a Glow-worm rather than a Vaillant, but it's still Group Service of course, and the same heat exchangers. I wasn't there but my customer said the engineer was very abrupt and seemed like he didn't want to do the job as soon as he walked in the door. Maybe just a bad egg rather than an indication of the company as a whole

Never meant to offend in any way Andrew, sorry if my post came across as that,just recommended a FPR as in my opinion was the best option for the OP, manus engineers are under so much pressure these days

 

[muggles]

No offense taken @ianmcd just felt I should clarify my comment for everyone benefit

 

[gtg]

Thanks both for your input, much appreciated

 

[ScottishGasMan]

I switched the boiler off this morning and increased pressure to around 2 bar. Put a bucket under the condensate pipe and saw this about 4 hours later

What was the pressure at 4 hours later? thats not a lot of water considering there would still be condensation collecting in the heat exchanger for a short while after use and working its way down through trap etc

However that definitely isnt the normal colour of condensate (its normally no different to tap water to the eye) however on occasion you do get a orange"ish" material building up in the condensate trap similiar to that colour.

 

[gtg]

I can’t remember to be honest, I’ll need to run the test again. I’ll aim for about 12 hours next time, so will have to find the right time in the next couple of weeks.

What I can say is there was almost nothing in the bucket after the first hour, and that quantity built up steadily over the 4 hours.

Could I add some dye through a rad and see if that ends up in the bucket? Or could that open up a load of different problems?

 

[Mottie]

What about buying some litmus paper and compare the pH of the water in the rads and what drips from the condensate after a period of time - I’m assuming the pH of condensate would be different to what’s in the system? Perhaps take a pH reading of your condensate first as a test?

https://www.ebay.co.uk/itm/Litmus-p...811660?hash=item23b84b824c:g:8EwAAOSwi6Jcip5M