Boiler water pressure

Postby kbrownie » Fri Nov 09, 2007 7:07 pm

Hi all,
I have a vokera boiler and the pressure dial is up to 3.5 bar in the red!
Tried bleeding rads went down whist heating off, then back up when heating on.
Any help would be very nice and save me the from ear ache from Her Majesty!
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Simply Build It

Postby bobplum » Sat Nov 10, 2007 12:08 pm

have you done any work on the heating system ie new radiator if so sounds like you have too much water in the system whan lying idle and cooled down the pressure should read ,on average 1.0 to 1.5 bar,consult you users guide to confirm
if its higher i would drain some water out and level it out using the loop fill and get to what the users guide says and try switching on again and see what happens
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Postby kbrownie » Sun Nov 11, 2007 11:32 am

HI bobplum,
Thanks for response, not had anything newly installed regarding bolier for about 18 months, had new heat exchanger fitted (the boilers about 5 years old not been the best of purchases) I'll look for manual and troubleshoot. Should I release water using main rad draining valve or using the valve used to bleed from top?
I,ll tell you how I get on after going through manual/users guide.
Thanks again
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Postby kbrownie » Wed Nov 14, 2007 5:46 pm

Hi drained water out of main rad, presure dropped to about 1.25 bar.
Didn't put heating all night (lovely wood burning stove, in front room). Returned to boiler later in evening and the presure had risen again to 3.5 bar. would much appreciate words of advise on the solution to my problem.
Please help
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Postby 2n3055h » Thu Nov 15, 2007 8:42 pm

Your expansion vessel needs refilling with air. When the water in your system gets hot and expands it has no where to go.

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Postby andf380 » Thu Nov 15, 2007 11:35 pm


Are you sur the filling loop is not allowing ater into the boiler make sure the valve is completely turned off drain it down to 1.2 bar and the pressure should stay constant.
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Postby Colin001 » Fri Nov 16, 2007 12:28 am


Is your filling loop still connected? If so i would check that the valve is fully turned off and then disconnect the filling loop from the system.

This will ensure that there is no chance of the system being topped up with additional undesired water.

If there is a fault with the valve to the filling loop you will soon know about it so pop a bucket underneath before you start and leave it there overnight.

With any luck this should solve the problem.
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Postby kbrownie » Fri Nov 30, 2007 10:41 pm

Hi again,
tried all suggestion and very much appreciated to all who have given advise, bot no joy drained water out disconnected loop but pressure still rises in to red weather heating on or not. Could it be the heat exchangers gone again? I had this replaced about 14 monthjs ago. really frustrating this boiler was claimed (not by me!) to be the rolls royce of boilers, have i really bought a skoda?
Again thanks for all input, great knowledge out there.
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Postby peter the plumber » Sat Dec 01, 2007 6:38 pm

I don’t think it’s worth fixing.

Most boilers run for years without any problems, there reliable and do there job.

They’re something wrong with design of this boiler, there seem to be a few people with the same fault.

Most of the posts I have read on these boilers go back to 2003.

I don’t know how old your boiler is, but if you’re spending more than about £300 per year repairing it, just give up and replace it.

I know it’s not the cheap option, but it would save you and your family a lot of trouble.
peter the plumber
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Postby ollie83 » Sun Dec 02, 2007 3:38 pm

if you done everything you said then it is the DHW heat exchanger. this is not very common but if it has happened before maybe its a fundamental flaw. good luck. Ollie
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Postby kbrownie » Sun Dec 02, 2007 7:07 pm

Hi peter the plumber,
thanks for advise, the boiler is about 5 an half year old, had servive engineer out to it twice while under warranty and had two repairs on it since, been a bit of a headache. Spent about £200 on it last time and sounds like the same thing again, the plumber who fitted it originally, used plastic pipes on the links to the rads (not a big fan) I have noticed that when I drained it the water was very murky, There was an inhibator put in it when last flushed and drained, is it the plastic piping causing this problem? Anyway I am going to replace it with a new one as advised.
Cheers for info.
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Joined: Mon Mar 05, 2007 9:36 pm

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