I have a Remeha Avanta Plus 28c combi boiler. About a month ago we stated to need to top the boiler up every few days. The copper pipe outside was wet, so I drained down to check the expansion vessel which was flat. Tried pumping it up, but wouldn't hold pressure so replaced vessel.
This his now stopped any water coming out of the outside pipe, but we are still losing pressure, but now at a slower rate. Only thing I could find that was suspect was the plastic air vent on top of the boiler's pump. This has some white crusting on the body around the cap. When I took the vent's cap off, there was a very small amount of water up inside the cap. Hardly any more than a drop or two.
Is it normal to have white water stains on the body of the vent around the cap? Should I be worried about the very small amount of water up inside the cap? In a normally working vent, should there be a slight weep/discharge of water that gets expelled with any air that comes out - or should no water come out at all?
Thanks for any advice and help. I have checked everywhere else, ie. all downstairs pipes/rads/valves/bleed plugs, etc, etc. Next step is to go in loft (bungalow - microbore pipes in loft) and check all pipes and joints. Unfortunately, I can't turn the flow and return valves off on the boiler to see if leak is in boiler or elsewhere in system, because the valves are seized. It's obviously a small amount of water/pressure that's being lost, because if I leave it for a week for the needle to go down to just under half a Bar, it only takes a few seconds of opening the fill loop for the needle to jump up to just over 1 Bar.
This his now stopped any water coming out of the outside pipe, but we are still losing pressure, but now at a slower rate. Only thing I could find that was suspect was the plastic air vent on top of the boiler's pump. This has some white crusting on the body around the cap. When I took the vent's cap off, there was a very small amount of water up inside the cap. Hardly any more than a drop or two.
Is it normal to have white water stains on the body of the vent around the cap? Should I be worried about the very small amount of water up inside the cap? In a normally working vent, should there be a slight weep/discharge of water that gets expelled with any air that comes out - or should no water come out at all?
Thanks for any advice and help. I have checked everywhere else, ie. all downstairs pipes/rads/valves/bleed plugs, etc, etc. Next step is to go in loft (bungalow - microbore pipes in loft) and check all pipes and joints. Unfortunately, I can't turn the flow and return valves off on the boiler to see if leak is in boiler or elsewhere in system, because the valves are seized. It's obviously a small amount of water/pressure that's being lost, because if I leave it for a week for the needle to go down to just under half a Bar, it only takes a few seconds of opening the fill loop for the needle to jump up to just over 1 Bar.
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