New house. New boiler. New problems.

[Sponge]

I moved house just under 4 weeks ago and I have a problem with my Vokera Compact 25 boiler.

The boiler is relatively new - under 3 years old.

After moving in I noticed the 'PRV pipe' was dripping constantly. The pressure seemed high at 2.5-3 bar. Despite this drip, the pressure wasn't dropping.

I had an NPower boiler policy at my old address and switching address resulted in that policy being cancelled and a new one being set up. Consequently, I'm due a first inspection/service on the 11th June.

My concern is the engineer will arrive, see the dripping pipe and diagnose an existing fault. Either resulting in the policy being cancelled, or an expensive quote for remedial work. I'm debating whether to reschedule the NPower visit and get someone else in to sort the boiler pre-inspection.

So, back to the fault:
A drip, but no loss in pressure.
Pressure hangs around 2 bar.
Boiler appears to function normally in all other respects.
I drained the boiler earlier today, down to 1 bar. (Used drain valve, not PRV.) The drip all but stopped.
Within 15 minutes the pressure had gone up to 1.5 bar and withing 30 minutes the gauge was showing 2 bar again. Dripping increases back to previous levels.
Turning on the heating results in the pressure going up to about 2.3 bar within 30 minutes and sitting there.

I was hoping you knowledgeable chaps could suggest possible causes and offer some suggestions.

Thanks in advance.

 

[gas_man_gaz]

the pressure relief valve is passing which is why you have the drip.
it also sounds like either the filling loop is passing or the heat exchanger is allowing the mains water into the central heating circuit, the 1st is a cheap repair the 2nd isn't
if ya a gambling man wait till n-power turn up and see what they say or give um a bell and they will prob offer some sort of fixed price repair

 

[HERTS P&D]

Drain the boiler and refill to 1 bar then disconnect the filling loop, see if it goes up, if so then its problem 2. If all ok then drain down and apply inhibitor and refill again.

Andy

 

[Sponge]

I presume the boiler-end of the filling loop will be the end of the braided hose without the 'tap' on it?

Can I just disconnect the boiler end? Or do I need to close any other valves first?

My previous boiler had a permanently connected filling loop and I've never disconnected one. I'm worried I'll disconnect the wrong bit and pee water everywhere.

Bottom end of braided pipe to be removed?

Untitled

• Sponge
• 10 Jun 2013
• 1

 

[Sponge]

At 1330 I drained the system to 1 bar and disconnecting the filling loop.

It is now 1410 and, touch wood, the pressure is still at 1 bar. This is good, isn't it?


The PRV is still dripping a little. This suggests the PRV is stuck open a little by debris or something, doesn't it?

So assuming the pressure stays at 1 bar, the only remedial work required is a new PRV?

 

[45yearsagasman]

Yes, change the PRV.

 

[Sponge]

The NPower guy comes tomorrow. I'll leave it alone for now. See what he says. If he says the work needs to be done before he signs it off and starts the service plan, I'll see if he quotes for it and then take it from there (get other quotes).

What would be a ball-park figure for getting someone in to change a PRV? If NPower's quote is reasonable, I'll just let them do it.

I'd consider doing it myself, but if NPower want to see documentation proving the works been done I imagine it'll have to be registered company, not DIY.

 

[Agile]

The PRV will probably stop dripping after a few hours/days.

But if the filling valve was leaking water into the system then water should have been coming out of that!

Tony

 

[Sponge]

I was going to query that.

I removed the filling loop and dried the valve. No water continued to weep from the valve.

I got up this morning and the pressure had dropped overnight to 0.5 bar.

I reconnected the filling loop and topped it up to 1 bar. Turned off the tap. It sounded like water was still entering the system and the pressure gauge was still slowly rising. I double checked the tap - yes, off. Pressure continued to rise and levelled off at 2.2 bar.

Then the NPower guy turned up and he still here.

I obviously didn't have time to redrain the system to 1 bar - try and make everything look normal - so we will see what he says.

 

[mickyg]

I see stevie wonder plumbing is still going strong !

 

[Sponge]

Thank you for contribution.

Well it turns out it was the filling loop isolation valve that was at fault. It has been constantly filling the system, despite the valve being off.

The other day, when I reported removing the filling loop and no water coming out, was an anomaly.

I was disconnecting the filling loop again, but this time water was continuously pouring from the isolation valve as I loosened the hose nut. I turned off the water at the mains, then disconnected the filling loop. I could see the isolation valve was closed, but when I gradually turned the mains back on again water would pour from it.

So I replaced the isolation valve and that's now sorted. However, I'm still faced with the constantly, albeit slowly, dripping PRV and losing pressure over time. (It dropped from 1 bar to 0.2 bar overnight.) But I'm going to leave the PRV for someone else to replace.

Thanks to everyone for your constructive comments, advice and assistance. Thanks for being my sounding board.