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Discuss Leak on pressurised heating system!!! in the Plumbing Jobs | The Job-board area at PlumbersForums.net

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ct8282

Hi peeps. I'm new here and have stumbled across this forum in a desperate effort to try and resolve the ongoing nightmare of my leaking heating system.

Cutting a 7 year story as short as possible then....

I came home from work about 6.5 years ago to find my boiler making a hell of a noise. When I opened the cupboard door in a panic I soon realised that the pressure of the system was '0' and the boiler was trying to run but couldn't circulate anything. I managed to find the refill loop and topped the system up. Things carried on as normal for a couple of weeks until the problem occurred again. I realised there was a leak so I called out a plumber who filled the system with 2 bottles of leak sealant. This seemed to fix the problem so I forgot about it and got on with my life.

Summer came and the heating system was not being used as to be expected. Then winter came and it was time for the boiler to start getting it's usual daily pounding. Within a couple of weeks I noticed the pressure had almost completely dropped again and it has been a battle of topping up the system periodically ever since. Sometimes the pressure will drop only 0.5 bar in the space of2 or 3 weeks. Sometimes it will drop almost to 0 in the space of 1 or 2 days. It varies and there doesn't appear to be any consistency at all.

I called in a plumber and a consultant chap to investigate and they spent nearly a whole day isolating all of the legs from the manifold, and used a device which pressurises the leg and then you wait to see if a pressure drop is observed. None of the legs showed up a pressure drop and the consultant chappy started saying that I might have a leak inside the boiler itself. However, they investigated the prv and drainage pipe and couldn't find any problems there either. Based on the characteristics of the pressure increase when the heating comes on (0.5 bar increase) they concluded that the expansion vessel is not to blame either. I have always been convinced that the leak is in the pipe work somewhere as my immediate neighbour had similar issues and they eventually found a poor joint behind the wall of their bedroom radiator.

So, all this work but the problem remains! However, I have now sold the flat and the new occupants are due to move in to the property in a few weeks and I am desperate to get this resolved before we exchange as I couldn't bare the thought of them inheriting this problem. They are first time buyers and are young and don't have much money. I want to do the right thing but also need to get moved out asap as my partner is expecting our first baby in a few months and we are trying to purchase a house.

So, tonight I have spent hours trawling the web and have found this forum which has had some interesting info. I also called a specialist leak detection company who gave me advice over the phone. They said that based on the inconsistent characteristics of the pressure drop this would certainly imply that the leak is inside the boiler. They told me to pressurize the system, close of the flow and return pipes to the boiler (using the quarter turn screw) and then watch to see if the pressure still drops. They said that if it does this proves that the leak is inside the boiler.

I have done this and the pressure dropped about 0.2 bar in around 90 mins. Does this mean that I have at least identified that the leak is indeed inside the boiler???

Any expert advice would be greatly appreciated as this has been plaguing me for so many years now. :sad3:
 
if it loses with the system isolated then yes its boiker

Ok, thank you. So any ideas on the cause. I've read that it's unlikely to be the expansion vessel as the pressure increases normally when the heating comes on. Could it be the plate heat exchanger or something else?
Any ideas on how easily it can be fixed and hoe much this might cost?
 
If there are no signs of an external leak, then the only explanation left is an internal leak to the heat exchanger with the leaked water being removed through the condensate trap.
Before you jump in though, 0.2 bar drop could also be due to a drop in temperature between readings. Make sure that it does keep dropping.
 
If there are no signs of an external leak, then the only explanation left is an internal leak to the heat exchanger with the leaked water being removed through the condensate trap.
Before you jump in though, 0.2 bar drop could also be due to a drop in temperature between readings. Make sure that it does keep dropping.

Thank you very much indeed. I will wait for the temps outside to increase a little so I can do the same test and leave the boiler off throughout the day.

Sorry to ask another question but how difficult and costly will it be to have the heat exchanger checked/repaired/replaced?
 
If you are going down that route you may want to replace boiler some of these heat exchangers can be expensive never done one on a icos but could be ÂŁ400.00 +.
 
If you are going down that route you may want to replace boiler some of these heat exchangers can be expensive never done one on a icos but could be ÂŁ400.00 +.

Surely replacing the boiler would several thousand...?
 
Lol no a boiler not anywhere near that price
If you give your location there may be a member on here near you to give you a price
 
No, heat exchanger / labour arround ÂŁ600.00 You could fit a new 24Kw boiler for around ÂŁ1200.00 as a stright swap shop around for price some good deals on at the moment.
 
Thank you. I just figured a new boiler would be like ÂŁ3k or more.

If I had some form of insurance would this type of thing be covered under the policy? Would they look to fix the issue or would they replace the boiler under an insurance policy?
 
No your house insurance won't cover this as it would be under wear and tear I'm afraid
 
Did anyone check the safety valve? It may have a weak spring causing water to escape outside.
 
If you confirm it's the boiler at fault the cheapest option is an Ideal fixed price repair.
 
I agree with Mike Jackson ref the fixed price repair ! but most will not cover Main Heat Exchanger, their`s also a couple of other parts they will not cover, ask if you call what is coverd ! :mickey:
 
Before you go down that route, shove a bottle of leak sealer in. It's only about ÂŁ6 from Toolstation and sometimes does the trick, so worth a try.
 
Be careful with leak sealer some boiler Manufacturers DO-NOT advise it !! :ban:
 
Update on this. I have since spoken with a plumber and he does not believe it is a leak inside the boiler as there are no visible signs of water coming out of the prv/overflow pipe outside, and there is no sign of water dripping out the bottom of the boiler and never has been. He is convinced the leak is on the pipework somewhere.

So, I have done some more investigating and today I took away the foam covers from the pipework around the cylinder. Running my fingers around the bit nuts and screw threads there is very clearly water leaking at these joins!

I have shown these areas with the read rings. At the top red ring there is a brass tap (no idea what it does) and this feels wet, and the pipe coming down from this tap is wet.
The blue rings show very obvious corrosion to the pipes.

The question then, would these leaks cause the pressure drop that I have been experiencing for several years now?

cylinder v1.jpg
 
Looking at photo the right hand looks like cold water main in and hot water out / the one on bottom left is from boiler, but floor looks dry, some joints need sorting out but do not think this is were you are looseing pressure, if you are sure that their are no leaks on boiler, the floor looks dry around tank, then you must have a leak on heating system.
You say that you have spoken to another Plumber (Hope he is GSR) But has he look`d at boiler to confirm that it is no at fault ??
 
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Hi,

Looks like the joints outlined did weep, as the marks are now white on the one I could see they have probably sealed themselves (not unusual especially in solid fuel with F/E tank) I agree the floor should be wet even from 1/2 litre of water constantly dripping on it.

Having ruled out the boiler, valves and all visible pipe work how about asking your plumber to disconnect the coil in the cylinder and do a pressure test on it?

They have been known to leak and as you have been constantly topping up the heating system the water is most likely clear and there is no Fernox (or similar) left to taint the water in the cylinder.
 
When you isolate the boiler from the system using the quarter turn valves on the flow and return pipework what pressure drop do you get if you isolate it while you are at work all day?

If you are getting continued pressure drops past the 0.2 bar mark then your leak is in the boiler. I would say even 0.2 bars if you are isolating it when the system is cold is pointing to the boiler.
 
When you isolate the boiler from the system using the quarter turn valves on the flow and return pipework what pressure drop do you get if you isolate it while you are at work all day?

If you are getting continued pressure drops past the 0.2 bar mark then your leak is in the boiler. I would say even 0.2 bars if you are isolating it when the system is cold is pointing to the boiler.

Would there not be visible signs of water under the boiler if this were the case? Surely that water has to go somewhere?
 
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