sealed pressurized system - problem

[al]

Help please for a rookie!!

I have a sealed pressurized heating system running off an oil-fired burner. For some time now there has been a loss of pressure in the hot water taps, to the point now where if one tap is on nothing will come out of any other tap. The cold water is fine. When it was first installed five years ago the hot water was the same pressure as the cold. I remember vaguely having a problem with a leak coming from the top of my hot tank a couple of years ago from a little red knob which was loose. I tightened this down, which i'm not sure I should have as it looks like some sort of pressure relief blow-off. Any help would be greatly appreciated

[Andy Hall]

It would be advisable to seek the help of a professional plumber with a sealed hot water system qualification.

It would be even more advisable to switch the system off until you have done so

[cynic]

Chances are you have a partial blockage in the inlet to the system, eg a strainer may have slowly accumulated debris or a stone may have passed into the system from the water main and be lodged somewhere restricting the flow

No you definitely should not. I'm not sure anyone dim enough to do this ought to work on your system!

[David Hansen]

On 23 Sep 2006 03:48:11 -0700 someone who may be "al" wrote this:-

Hopefully it is not sealed, but has the variety of safety devices specified for such systems.

Get somebody who knows what they are doing to look at it. Hot water under pressure is not something to experiment with.

[adder1969]

As far as I can tell, there's nothing on a relief valve that you can screw down to stop it leaking which will also affect it's performance. If it is a relief valve try testing it by lifting the lever or turning the end - water should come out (maybe try it cold/warm not hot). Do a google image search on a valve and see if it's the same.

There should be a one-way valve in the supply to the tank so maybe that's got stuck.