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PostPosted: Sun Jan 05, 2003 4:52 pm 

Joined: Sun Jan 05, 2003 4:39 pm
Posts: 1
Hi All,
Hot water works fine, central heating very tempremental - sometimes need to run hot water to encourage heating intp life.
pressure seems to remain stable.

However, after reading some of the othe posts in here about combi boilers could someone clarify the following for me:
1) The expansion tank is not charged, when I try to pump it up, it charges but if I then release some pressure - i get frothy water . Is the tank knackered? It does not release water or air during normal (ie broken) operation of the system.

2) The valve next to this tank is marked 3 bar and will not completely shut off -there is a very slight leak - so slight that use of the bolier drys it up unseen - can this be left or should it be changed?

3)What should the pressure be set at, and should it be done by pumping up the expansion tank or introducing more water using the inlet to the system - this seems to have the same effect.



 Post subject:
PostPosted: Sun Jan 05, 2003 4:56 pm 

Joined: Fri Nov 29, 2002 10:10 pm
Posts: 93
1) sometimes they collect a bit of water, through small internal leak. Theres a rubber baloon in there that can split. Doesn't really seem to matter if it's a slow leak - others may disagree.
You have to release all the system pressure to get the pressure in the expansion vessel right. Do that by letting water out. Then pump the EV to about 20 psi. If you can't because of the leak, you need a new EV.
2) you need to stop the leak. Some of those valves come apart, but most you have to change. There's only a metal to metal seal inthere so it can be just a bit of dirt.
3) open the filling loop to give you 1 - 1.5 bar on the gauge. (1bar = 15psi)

Your CH problem sounds like a sticky diverter valve. I'm not familiar with your model.

This message was edited by Will on 1-5-03 @ 5:04 PM

 Post subject:
PostPosted: Sun Jan 05, 2003 9:31 pm 

Joined: Tue Apr 23, 2002 2:55 pm
Posts: 2845
Location: North London ONLY
As far as I know it is only Vaillant that use the metal seals in pressure release vavles - the red handle types have a rubber washer - best to change it they are not expensive.

Will's advice on the EV is spot on though - except in the importance of a small leak - I would not say it was a minor thing that could be ignored.

As Will also said you have a diverter valve problem with the CH...That to should be changed. Look at hte cost first though - it is an old boiler, and if all three things need changing then perhaps it is time to change the whole thing.

Regards :)

Dan Robinson
Director - Jennings Heating & Plumbing.
CORGI 138845
Tel: 0208 961 5936
email: plumbnet@hotmail.com

Regards :)

Dan Robinson
Jennings Heating & Plumbing
CORGI - 138845
Email: dan.robinson@blueyonder.co.uk
Phone 0777 5731339

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