RAVENHEAT RSF 820/20 COMBI, CH Pressue Drop


21 Feb 2005
Reaction score
United Kingdom
My dad's RAVENHEAT RSF 820/20 COMBI, is losing CH pressure with no signs of leakage from the boiler or pipework. The pressure needs to be re-primed by the filling loop approx. every 48 hours.

Is it possible its escaping into the DHW?

Any help is greatly appreciated.
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Thanks for the reply.

There are no signs of water escaping from there.
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But how could you tell if the DHW pressure was increasing?

Is this possible anyway? The DHW system would have to be at zero pressure at the point where the CH was leaking into it :?:
It is not possible for the leak to be going into the DHW then.

Any other suggestions?

P.S. The diaphragm was streched and split on my Vokera combi. I've fixed it and now. No more cold showers!
yeah... the suggestion was you have a leak... :LOL:

100% definate, somwhere on the heating circs, the water has to be going somewhere, and as the DHW pressure is higher then the system pressure it sure as hell isn't going there.
Check all your radiator valve shaft seal - you'll have to take the plastic covers off.

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