Any plumbers out there?

[peanut]

Hi all,

My oil combi boiler is losing pressure, fast.

I've now discovered the pipe that runs outside is leaking very hot water when the boiler is on.
I've also noticed the pipes in the boiler are possibly a bit hotter than usual, though haven't noticed particularly scalding water.

I think, therefore, I have a faulty pressure relief valve and or a dodgy thermostat.

My question is.....if this is the case how much is it likely to cost me to get a plumber to fix it?

Thanks in advance.

[Mikey]

It could be a couple of different things, we had a similar problem with ours about 2 months ago with a loose pressure release valve being the obvious leak, it cost us roughly £200 for the service and repair.

Its important to get your oil boiler serviced annually, to ensure you don't run into problems, I know from experience.

[Potstubsdustbins]

Sorry Mikey this sort of thing would be helped by an annual service. Three things can cause system pressure lose.

(a) A leak somewhere on the heating side of the system, unlikely you would have noticed it.

(b) Defective safety discharge valve, good possibility, dependant on make of boiler no more than £80.

(c) Defective pressure vessel again a possibility. Keep your fingers crossed it isn't.

Check by doing the following, top up the system pressure to 1 bar. Turn on heating circuit and observe pressure gauge, if the pressure rises to 2 1/2 to 3 bar quickly and the water is discharged outside its the pressure vessel.

If this happens let me know including make and model of boiler and I will give you further advice.

Colin.

[peanut]

Hello Colin,

I have done as you said, topped up to 1 bar, turned on heating and hot water and the bar barely moved....no water leaked from the outside pipe either. (but guess that was because pressure was too low)

It is a Warmflow U70HE


Thanks for your help,

Joanna

Sorry Mikey this sort of thing would be helped by an annual service. Three things can cause system pressure lose.

(a) A leak somewhere on the heating side of the system, unlikely you would have noticed it.

(b) Defective safety discharge valve, good possibility, dependant on make of boiler no more than £80.

(c) Defective pressure vessel again a possibility. Keep your fingers crossed it isn't.

Check by doing the following, top up the system pressure to 1 bar. Turn on heating circuit and observe pressure gauge, if the pressure rises to 2 1/2 to 3 bar quickly and the water is discharged outside its the pressure vessel.

If this happens let me know including make and model of boiler and I will give you further advice.

Colin.

[Potstubsdustbins]

Hi Joanna,

The system's normal running pressure is 1 bar. The safety discharge valve should only open and release water at 3 bar. The spring sometimes goes weak and they can discharge at a less pressure. If the valve is not now discharging it would seem that might be OK. Something must therefore have caused a pressure increase so that the valve operated.

So we are left with a couple of alternatives, easiest one to check is the filling loop its self. If yours has a woven stainless steel flexible connection try the following. Make sure the filling valve is turned off and undo the flex at the joint nearest the filling valve. There will be a little water in there but nothing to worry about. Once you have done that make sure there is no water not even the slightest dribble coming from the valve. If there is thats your problem that tiny dribble is gradually building up the system pressure and opening the discharge valve.

After that we go to the boiler thermostat or the expansion vessel.

Colin

[peanut]

Hi Colin,

The hot water and heating are all switched off.

The current pressure reading is still reading 1 bar since I did as you said.

But the low pressure light is on and remains on until the pressure is just over 2 bars.

I have been topping up to between 2 and 3 bars in order to keep the low pressure light off.

I'm very confused!

I do have a silver flexible hose so will try your last suggestion!

Thanks so much for all this.

Hi Joanna,

The system's normal running pressure is 1 bar. The safety discharge valve should only open and release water at 3 bar. The spring sometimes goes weak and they can discharge at a less pressure. If the valve is not now discharging it would seem that might be OK. Something must therefore have caused a pressure increase so that the valve operated.

So we are left with a couple of alternatives, easiest one to check is the filling loop its self. If yours has a woven stainless steel flexible connection try the following. Make sure the filling valve is turned off and undo the flex at the joint nearest the filling valve. There will be a little water in there but nothing to worry about. Once you have done that make sure there is no water not even the slightest dribble coming from the valve. If there is thats your problem that tiny dribble is gradually building up the system pressure and opening the discharge valve.

After that we go to the boiler thermostat or the expansion vessel.

Colin

[Potstubsdustbins]

Joanna,

I have just checked and the system pressure would normally be 1 bar.

If you have been topping it up to between 2 & 3 bar this would cause the discharge valve to operate when the system warmed up and the water expanded.

This is starting to look like a faulty low pressure warning light. If your filling valve is shutting off correctly. Ignore the low pressure warning light, leave the system at 1 bar and see if everything works. If it does you have a choice, leave the system at 1 bar and let it continue to run (this will do no harm at all) or if you feel the need get an engineer in to check and if necessary change the low pressure warning light.

Colin

[peanut]

Not a chance of me being able to undo that hose!!!

[Potstubsdustbins]

OK, with your last post lets have a change of tack do as I suggest in the post above. Lets find out if its a faulty low pressure warning light.

Colin

[peanut]

Thanks so much Colin.

I shall try leaving the water on and see how I go, i have been switching the hot water off completely because of the dropping pressure and heating is off anyway, just been constantly concerned by the low pressure light.

The only other thing I've noticed, which is what started me on this investigation is that when I run a bath, i've been running out of hot water....so I would top the system up again to about 3 bars.....then i'd get enough water, but by the time i'd get out of the bath the pressure light would be on and pressure reading would be almost if not zero.

Do you think this is a fluke, made worse by my constantly topping up so high?

Joanna,

I have just checked and the system pressure would normally be 1 bar.

If you have been topping it up to between 2 & 3 bar this would cause the discharge valve to operate when the system warmed up and the water expanded.

This is starting to look like a faulty low pressure warning light. If your filling valve is shutting off correctly. Ignore the low pressure warning light, leave the system at 1 bar and see if everything works. If it does you have a choice, leave the system at 1 bar and let it continue to run (this will do no harm at all) or if you feel the need get an engineer in to check and if necessary change the low pressure warning light.

Colin

[Potstubsdustbins]

Constant topping up will not have helped.

Its hard to diagnose properly from this distance. They may well still be a problem, I have to go now but will be back later. Let the system run whilst it is still at 1 bar and let me know how you get on. If the boiler is still working in about an hour check the system pressure and let me know if it rise's above 1.8 bar

Colin

[Florence Fennel]

You're lovely Colin. Sorry, just had to butt in to say that. Hope you get everything sorted peanut.

[peanut]

Thank you Florence....he is a star! I think there should be a "Potstubsdustbins" Fan Club ...I'd be in it!

A quick update for you Colin, I've had the hot water on since we last spoke, the pressure got up to 1.9 bars then stayed there. I haven't actually used any hot water and the pressure has now gone down to 1.2 bars.
The strange thing is the low pressure light hasn't come back on.....yet!

I usually turn my boiler off over night to stop it firing up and wasting oil in the night. I wonder if that has upset it?

Anyway, the test for me will be tomorrow morning when I have a bath......then I'll know if the pressure stayed overnight and if I get plenty of hot water.....watch this space!!!


I really can't thank you enough Colin, for your time and advice.

Big, big thanks,

Joanna

[veggiechicken]

Thank you Florence....he is a star! I think there should be a "Potstubsdustbins" Fan Club ...I'd be in it!

There is one already

[Potstubsdustbins]

Now then ladies you'll make blush, just trying to help after all thats what the vines about so why restrict it to GYO.

Joanna,

Turning the boiler of overnight shouldn't have any ill effect.

Whats going to happen overnight is the system will go cold and the water will have contracted so before you start up in morning the check the system pressure it should be somewhere near back to 1 bar. Let me know tomorrow please.

Stupid question time, do you cycle and if so do you have a pump for your tyres? There is a good reason for this question anyone who comes up with the right answer gets a virtual lollipop.

Colin.