Boiler leak

Haley00

I need advice. My boiler has been loosing pressure since April I have had 2 people go under the floor and countless amount of people look at the boiler and nobody can find a leak. I have al sorts of suggests a few I have had done to no avail including PRV. I am running out of ideas and money and need any suggestions possible to identify the problem. Each investigation seems to aggravate a new problem with now the pump packing up and the result of barely warm radiators. Would a whole new system solve this problem? Im a child minder so use my home for work and don’t know what else to do 🥺

Apodemus

A whole new system seems a bit of a drastic step!   What type/age of boiler do you have? 

Could be a leak in the condenser, which would lead to increased dripping from the condensate drain - but if this is plumbed to a proper drainage pipe you wouldn't necessarily see this.  Any competent engineer should have already checked this as condensers are a weak point in some boilers.

Bendy_House

Hi Haley.

As Apod says, it's astonishing that 2 folk have been out to look at this but cannot determine where the leak is coming from. At the very least, they should- very easily - be able to determine whether it's from within the boiler itself, or outwith the boiler, in the pipes and rads. This is done by noting the pressure in the system, and then turning off the two isolating valves under the boiler so as to separate it from the radiators; if the pressure still falls, then the leak is within the boiler.

Mind you, since the boiler needs to be off for this test, it would need to be a noticeable pressure drop if it isn't going to take days...

The other two obvious things they should have checked - and perhaps they have - is the PRV as you've mentioned, and this one is obvious as any water will be seen coming out the 15mm copper pipe outside the house - I'm sure they checked this? And the other is if there's any water coming out the condensate pipe that shouldn't be. The awkward thing here is that water - condensate - does come out at regular intervals in any case when the boiler is running. I don't know if some sort of tracing chemical can be added to the system and then detected in the condensate water?

Make and model of boiler? AND, how quickly does the pressure drop?

Does it run ok if you keep topping up the pressure? How often do you have to do this?

Haley00

I had at least 6 people out and nobody has isolated the boiler yet, how is this done? It’s definitely not the PRV as this has also been eliminated. 

The boiler is losing pressure daily ( if I put a bit more in then it’ll last 2 days) 
Its an ariston and is 10years old. I have also had that magic seal stuff ( not sure what’s it’s proper name is) put through the system to sort any little leaks and that didn’t work either. This is why I think the fault may be on the actual boiler not the pipes ? 

Haley00

 just to add the condenser pipe drips when the heating comes on but it doesn’t when it’s not as I have access to this pipe and have already looked. 

Belenus

Haley00 said:

 just to add the condenser pipe drips when the heating comes on but it doesn’t when it’s not as I have access to this pipe and have already looked. 

That is normal.

Another_Level

The expansion vessel may need it's air charge checked or it may be faulty in other ways, easy to check which should be done annually when the boiler is serviced 

Hope you get it sorted out 

Bendy_House

Haley00 said:

I had at least 6 people out and nobody has isolated the boiler yet, how is this done? It’s definitely not the PRV as this has also been eliminated. 

The boiler is losing pressure daily ( if I put a bit more in then it’ll last 2 days) 
Its an ariston and is 10years old. I have also had that magic seal stuff ( not sure what’s it’s proper name is) put through the system to sort any little leaks and that didn’t work either. This is why I think the fault may be on the actual boiler not the pipes ? 

Model of Ariston?

Most boilers - probably all - have isolating valves fitted where the pipes enter the unit (apart from the DHW output, PRV and condensate). Two of these will be the CH flow and return, and will be in 22mm, and almost certainly copper. If these are shut fully off, by turning them through 90o, then the 'system' water (ie the water that's sealed and under pressure) in the rads and pipes are fully isolated from the ditto inside the boiler. If the pressure still drops, then that indicates a leak from within the boiler. If the pressure remains constant, but then instantly drops when one of these valves is reopened, then that indicates a loss of pressure in the rads and pipes part.

For a relatively fast pressure drop like yours, this should be a pretty conclusive test, and simple to carry out.

You'd need to do this test for long enough to allow a noticeable pressure drop, and also have the boiler turned off - so no heating...

How long does it take for the boiler to show a noticeable amount of drop?

As Bel says, and I think you yourself understand this, it is normal for the condensate pipe to trickle when the boiler is running, but not after it's been off for a while. However, bear in mind it doesn't actually trickle constantly, but usually in 'slugs', so there will likely be non-trickling periods between slugs. So if you checked the condensate pipe with just a glance, then you may have missed the 'slugs'.

(The condensate empties from the combustion chamber via a syphon, a bit like a toiler flush. The level builds up until it reaches a tipping point, and then it flows out in a slug. Between slugs, there might not be anything showing.)

Is your CH effectively off overnight? If so, place a pot under the cond pipe. Check the contents in the morn.

Another_Level

Tbh there is well known methodology to apply, just needs personnel with fault finding knowledge. Not salesperson's 

Some repair/service technicians adopt the Devil's Advocate^  idea, they are instant failures although they are nice to talk to 
Ariston and similar boilers are known to be basic intro boilers with 10 year swap out timeline.

Ariston boilers are actually Ok but same as any gas boiler they need the same person to come back annually to do the service and keep a log of what was done.

Getting random service tech's for annual servicing  could result in the appliance being safety checked only 

Everything is fixable !

Dont invite a devil's advocate 

 

 

Haley00

The boiler has also been serviced in the last month and they detected no leak nor any problems and was under the illusion that the service would sort it!  The condense pipe is above my conservatory so I can hear it when it drips so I know it’s not that that’s the problem with that. 

Bendy_House

If you are 100% certain that the condensate pipe isn't trickling when it shouldn't be, and you are 100% certain the safety discharge pipe ain't trickling at all, and if you are 100% certain there isn't a leak actually coming from the boiler unit itself which would end up on your floor, then I think you can be 100% certain that the leak isn't from the boiler.

And that's usually bad news. 'Cos it's in the rad pipework.

Hang on - is this a combi or do you have a hot water cylinder? If the latter, then there's also the possibility that the heating coil (part of the sealed pressurised system) might be leaking, in which case the system water ends up in your hot tank, and hence, cold tank.

Either way, the next obvious test is to pressurise the system to a noted figure, and to shut off the two valves (and the boiler).

Leave for a few hours, and note pressure before and after reopening the valves.

If you post a photo of the pipes coming out t'boiler, we might be able to guide you. This is an easy DIY task, but only if you are happy to do it.