Worcester 28i Junior Central Heating pressure query

[r]

Hi All,

Wonder if anyone can shed any light on an issue with my boiler/heating system.

We recently removed a bathroom radiator temprarily while retiling. After it had been replaced we bled the radiators etc. The pressure had dropped at this point to zero bar on the boiler, so we topped it up via the tap to 1 bar.

Now when the heating is on, the pressure guage on the front of the boiler climbs rapidly from 1 bar to almost off the scale within around 30 mins (I have turned it off before it actually goes off the scale in case it is dangerous).

Any ideas on why this may be happening or should I call an engineer out?

Best wishes, thanks in advance, R

[Stuart Noble]

I know sod all about heating but I did have a similar problem to you. I had to bleed the rads a few times over a week or so before the guage settled down. Then I had to remove half a litre or so via a bleed valve to get it down to normal. The guage on my 24i is certainly very sensitive given the amount of water in the system as a whole. You wouldn't think a pint would make much difference one way or the other

[Lobster]

I'd say you've got an airlock in the system and it needs to be forced/bled out. I doubt all your radiators are hot, right?

David

[r]

Update! Thanks for the comments so far folks.

As I said, we'd set the pressure to 1 bar at about 6pm - system left off and when I checked at 9.30ish it's down to half a bar with no human intervention!

I popped the heating on and it's up to 3 bar within 15 minutes!

I've put it off again but a quick check of the rads and they all seem hot.

Very odd.

R

[Ron Lowe]

Rapidly increasing pressure like this suggests a failed expansion vessel, not a need to bleed.

A need to bleed would cause the system to have higher compressibility ( gas volume ), which would cause the pressure to increase less for a given temperature increase. That is not what you are seeing. You are seeing the opposite.

Like I say, looks like your expansion chamber is empty or goosed.

[<me9]

Sounds as if the pressure vessel has lost it's pre-charge. See the sealed system FAQ. It may be possible to re-charge via a tyre pump.

It seems to be down at the moment Ed?

[Ed Sirett]

Checked as working at 22:10 on 21/4/8. Demon are a fairly reliable and probably better than most ISP.

[<me9]

It's working fine now, but wasn't when I originally posted.