Plumber needed?

**blr123** · 19th March 2006, 22:54

Hi guys,

Any plumbers on the forum?

Had a bit of a flood today and it looks like the motorised valve on the combi boiler has failed and allowed the central heating to be pressurised to/by mains pressure..........would that be possible.........it was certainly up at 5bar pressure and blew a fitting..........hence the flood

........any thoughts would be appreciated

Bryan

**simonali** · 20th March 2006, 08:19

Are you talking about your central heating or your hot water going pop?

The only combi I've ever owned only had a gauge on the heating side and that was fed/topped up by a hand valve from the mains water supply.

**markspark** · 20th March 2006, 09:08

the central heating should be seperate to the mains water, and as simonali said it can only be turned on by hand!! check to make sure no little fingers have been messing with it!

**2ltrT** · 20th March 2006, 09:28

if the small heat exchanger broke down, it could let water, mains pressure direct into the central heating sysyem.

**blr123** · 20th March 2006, 14:14

Originally Posted by simonali

Are you talking about your central heating or your hot water going pop?

The only combi I've ever owned only had a gauge on the heating side and that was fed/topped up by a hand valve from the mains water supply.

It was the central heating............and yes the CH is topped by opening the mains valve then closing.........there is a pressure gauge and just above it is the motorised valve...........I think this is where they can cross connect as there would not be any other explanation as to why there was 5bar pressure..........what do you think?

Bryan

**chunkster** · 20th March 2006, 14:31

what type and make of boiler is it bryan, im a plumber/gas fitter, generally if the pressure in the heating system exceeds 3bar on the gauge, then the pressure relief valve will open and empty the pressure from the 15mm pipe that should be outside. if little fingers havent been playing then the only place where the waters can mix is in the hot water plate exchanger. theses are about £60 - £100 depending on boiler make
if this has caused a flood inside then the PRV is incorrectly fitted or has become faulty as it should blow before 5bar

**blr123** · 21st March 2006, 01:15

It's a Worcester.....not sure of the model.......will get taht tomorrow.

It was one of the radiator pipes that burst

Bryan

PS the relief valve has NOT been lifting

**2ltrT** · 21st March 2006, 01:52

I was tired this morning.... anyway ....
Another thing to check, is that there is no blockage between the pressure vessel & the ch flow... it’s generally a flexible hose.
If it’s blocked the pressure will slowly rise, when heating is on.

Its probs a good idea to check the pressure of the vessel whilst you’re on... a standard bike pump will fit... the correct vessel pressure will be in manufactures instructions.

If pressure is rising when heating is off is either the filler loop passing... or the heat exchanger has grown a hole.

I’d recommend the PRV is replaced, approx £10. The filler loop should always be disconnected after filling.