Temperature pressure relief valve dripping

Lulu58

ThisIsWeird said:

2020? I think you can rule out a new cylinder being required (and surely has at least a 5-year warranty in any case), so I would suggest a local plumber is the sensible move. He is G3, isn't he?

Not sure if the EV would be as well?!

Yes, the red EV is for the 'system' side as I described earlier - completely different circuits. You can tell that side is ok by observing the pressure gauge on the boiler. It's hopefully sitting at around 1 bar, perhaps a little above, and doesn't climb significantly as the CH is turned on?

I'm not sure if the cylinder or EV are registered for the guarantee.  We had a lot of work done on the house, including a new boiler but got caught up in the pandemic and couldn't move back until the June.  I don't know if the installer would have registered it.

The pressure gauge is still quite happy at around 1 bar.

I'll ask if he's G3 when he's here. There's nothing on the Gas Safe Register, but then there's nothing on any of the plumbers we know on there.

Lulu58

ThisIsWeird said:

Yes, if your motorised valves are sticking or faulty in another way, then that could affect the boiler.

The sequence of operation is: your timer (programmer) tells the CH to come on. This sends a signal to the room stat. If the room stat says "Yes, the room needs to be warmer", then it sends a signal to the CH motorised valve. The motorised valve opens, and trips a microswitch when fully open - this sends the 'on' signal to the boiler, and it only then comes on.

A dodgy microswitch, or sticky valve, and the boiler won't come on.

You can ask the plumber to check that the valve appears to be working smoothly?

Thank you for the sequence, ThisIsWeird. Very helpful.

I'll definitely ask the plumber to check that the valve works smoothly.  

ThisIsWeird

Lulu58 said:

ThisIsWeird said:

2020? I think you can rule out a new cylinder being required (and surely has at least a 5-year warranty in any case), so I would suggest a local plumber is the sensible move. He is G3, isn't he?

Not sure if the EV would be as well?!

Yes, the red EV is for the 'system' side as I described earlier - completely different circuits. You can tell that side is ok by observing the pressure gauge on the boiler. It's hopefully sitting at around 1 bar, perhaps a little above, and doesn't climb significantly as the CH is turned on?

I'm not sure if the cylinder or EV are registered for the guarantee.  We had a lot of work done on the house, including a new boiler but got caught up in the pandemic and couldn't move back until the June.  I don't know if the installer would have registered it.

The pressure gauge is still quite happy at around 1 bar.

I'll ask if he's G3 when he's here. There's nothing on the Gas Safe Register, but then there's nothing on any of the plumbers we know on there.

In the very unlikely event there's a fault with the hot cylinder, then you should have consumer rights on your side at least. 
Chances are it's just an EV issue.
Good luck :-)

Lulu58

ThisIsWeird said:

Lulu, could you post a photo of your EV, please? Try and show where the drip is coming from.
Can you see a Schrader valve on it - a car tyre valve? Is there water seeping from that?

If it's from the copper pipe joint at the bottom, then it's likely just not done up properly (never was), and the increased pressure has exposed this. Easy for a plumber to fix.

You can safely remove the valve cap, and briefly press the valve pin - use something blunt. If it 'hisses', then hopefully your EV is still ok, and just needs more air. If nothing at all comes out, then there's no air left at all, but the diaphragm is still intact. But if any water comes out, it's kaput, so a new EV will be needed, which might make the fixed-price repair mentioned by hb143 a good call. However, if the EV is actually ok, and just needs air-charging (just like you'd do on a car!), then it could be costly, as recharging is just 20 minutes of pumpin'.

If you have a trusted local G3 GasSafe, then that's usually the best first call. Have you had it serviced at all? And, how old is it?

Hi ThisIsWeird, missed this post earlier.

I struggled to get a photo of the EV/pipe so will try and explain but the issue is as you've described above. The EV is above and to the right of the cylinder.  There is a pipe which runs from the bottom of the EV down to just above the floor of the garage.  It has a valve (?) on the end - one where you can attach a hose for draining a system. It's leaking from there.

The plumber (definitely G3 which is great) has been and tightened it up and I'll keep an eye on it over the next day or two.

He tapped round the EV and it sounds hollow which I understand is a good thing!

He is going to replace one of the mixer valves.  

The boiler is working fine and doesn't appear to have any problems. However, we may replace the motorised valve for the hot water as it is a bit sticky. As mentioned before, we've had problems with the three motorised valves since the new system was installed.

As the system has to be drained down, we may take the opportunity to replace all the motorised valves and possibly get valves fitted so we don't have to drain down the whole system going forward.

Thanks so much for your help and all the information given. I really appreciate it

ThisIsWeird

Good result - although a wee bit inconclusive.

Yes, a 'hollow' EV is a good sign, as there's clearly air inside it. But hopefully, when the system is drained down, he'll take the opportunity to check and reinflate as needed.

The drip from the bottom pipe - the drain-down connector - is usually a trivial cause, and most likely sorted by the wee tightening.

Not sure which 'mixer valve' he's referring to? Is this thermostatic, and blends the hot from the tank with some cold to provide a safe DHW supply?

Yes, if draining down, replace the whole of the motorised valves, body and head.

Cool :-)

 

Lulu58

ThisIsWeird said:

Good result - although a wee bit inconclusive.

Yes, a 'hollow' EV is a good sign, as there's clearly air inside it. But hopefully, when the system is drained down, he'll take the opportunity to check and reinflate as needed.

The drip from the bottom pipe - the drain-down connector - is usually a trivial cause, and most likely sorted by the wee tightening.

Not sure which 'mixer valve' he's referring to? Is this thermostatic, and blends the hot from the tank with some cold to provide a safe DHW supply?

Yes, if draining down, replace the whole of the motorised valves, body and head.

Cool :-)

 

It would have been good to understand why the boiler switched itself off but it's been working fine since. If it happens again I may call out WB as it's still under guarantee.

I think it may be my terminology with the mixer valve.  I've just looked it up and it's called a Caleffi Circlip Multibloc valve. Meaty thing!

I forgot to say that the system is serviced each year.

  

ThisIsWeird

Thanks.

That fellow combines two important devices in one. There's a pressure reducing valve (PRV), which prevents the cylinder receiving too much pressure from the mains, and then there's a pressure release valve which will open to release excess pressure if summat goes wrong.

The release valve has clearly operated on your system, since you saw the drips in the tundish. Why this happened is not known, but it could be a faulty PRV which allowed too much pressure in. Or he could be replacing it because, as said before, once the safety valve has opened, they tend to not seal up properly again.

Anyhoo, it's all in hand.

Why the boiler went funny, we can't tell. Almost certainly not connected with the cylinder issue, and probably most likely to do with a motorised valve head.

greenbee

Thanks for posting this - I read it, and the next time I went into the airing cupboard happened to notice a drip through the tundish. I checked the outlet pipe and it was very soggy. (I moved here in the summer, and heating wasn't originally high up the list).

I managed to get hold of a G3 qualified heating engineer (I decided not to use the installer/person who serviced ti previously, as i'm not convinced about the quality of the work) who came out and recharged the expansion vessel - it's all working fine now. He's of the opinion that it hasn't been serviced since it was installed (and apparently people don't always realise that pressurised tanks need servicing). He then serviced the boiler and wasn't impressed by the state of that. However, I was impressed by how thorough he was, and it made me realise that it's unlikely anyone who has serviced my oil boilers in the past has done it properly - they've never taken the amount of time he did and I've certainly never seen evidence of them cleaning the turbines. The cost was very reasonable, and he'll be coming back to replace the magnets in the filter as the plastic rod that holds them was completely broken (probably as a result of an earlier service).

He also diagnosed the fault with the heating coming on even when the thermostat isn't calling for heat as needing an electrician (not a huge surprise), saying that plumbers and heating engineers are generally not great at electrics. Which I suspect most of them would agree with - but I do now have clue as to a couple of potential causes, and an electrician booked to come out and look at it. None of which would have happened (yet) if I hadn't previously read this thread!

Lulu58

ThisIsWeird said:

Thanks.

That fellow combines two important devices in one. There's a pressure reducing valve (PRV), which prevents the cylinder receiving too much pressure from the mains, and then there's a pressure release valve which will open to release excess pressure if summat goes wrong.

The release valve has clearly operated on your system, since you saw the drips in the tundish. Why this happened is not known, but it could be a faulty PRV which allowed too much pressure in. Or he could be replacing it because, as said before, once the safety valve has opened, they tend to not seal up properly again.

Anyhoo, it's all in hand.

Why the boiler went funny, we can't tell. Almost certainly not connected with the cylinder issue, and probably most likely to do with a motorised valve head.

Thanks again, ThisIsWeird. Really helpful info.

Lulu58

greenbee said:

 None of which would have happened (yet) if I hadn't previously read this thread!

Glad my post and the terrific answers I've received have helped greenbee.

Sounds like your G3 engineer did a great job. Hope the electrician is as good and that you get everything sorted.