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sparkykink · Joined: 06 Jan 2007 Posts: 25 Location: manchester

Hi,
I have a rad in the loft which keeps filling with air, but when I bleed it it doesn't need a top up from the boiler so I don't think there is a leak.
If I leave it a week or so the pressure dial on the boiler shows an increase.
This only really started when I put an inhibitor in the system.
It's a sealed system boiler.
Just wondering whether there may be a problem, and if not can I get a "auto bleed" screw?
Any suggestions would be helpful.

Thanks,
Dave

AlanE · Posted: Sat Apr 12, 2008 8:48 pm Post subject:

Boiler?
System pressure?
Boiler last serviced?
Expansion vessel last checked?

Without above can only guess.

sparkykink · Joined: 06 Jan 2007 Posts: 25 Location: manchester

Hi,
Thanks for the reply.
The boiler is a worcester bosch and is 18 months old, checked by engineer and new pump fitted 15 months ago
Bar pressure is 1 bar when cold, rising to just above 2 when hot.
Expansion tank checked about 6 months ago.

AlanE · Posted: Sun Apr 13, 2008 4:17 pm Post subject:

Worcester Bosch narrows it down to around 100 posabilities.

Expansion vessel is either defective if pressure rises from 1 bar cold to over 2 when hot. Would expect it to go up a little but nowhere as much as that. If there is no problem with it then it is too small a capacity for your system.

Cannot understand why when you bleed a radiator, effectivly removing part of its contents that the pressure doesn't drop somewhat.

What inhibiter did you use and what size is system? If boiler is only 18 months old, with a new pump after just 3, is remainder of system just that old or is it a replacement boiler.

Full details are required as to boiler etc. Don't even know at this stage if it is a combi, regular or system boiler.

thescruff · Moderator Joined: 03 May 2003 Posts: 4400 Location: Bath

How big is the system, I agree the expansion vessel may be too small or need looking at.

Is there a strong smell when you vent the top rad.

sparkykink · Joined: 06 Jan 2007 Posts: 25 Location: manchester

Hello again,
I should have said earlier, you have helped me before (jan 07) when the boiler had problems after installation. (you may still have the postings)
It is a system boiler, and no there is not a strong smell when venting, it just lets air out and for some reason doesn't seem to lose pressure?
I have made sure the pump is off when bleeding the rad.