I hope someone can comment on my setup and let me know if I have a problem or not !
I have old gas central heating system, all was working:
gravity fed hotwater heating
radiators via pump.
We then had back boiler fitted to wood burner and replacement cylinder with 2 coil element type fitted by professional plumber, so water can be heated by gas or wood.
Can't seem to heat water from boiler
Can gravity work fast enough to transfer the heat, from cold.
When I try there is lots of scary banging and sound of water rushing through pipes, the input of cylinder gets too hot to touch, the bottom exit gets slightly warm, Water clearly not flowing through it properly.
Even with the radiators on, hot water doesn't seem to get heated, but as the pump is pulling water through radiator circuit it's hard to see why it would flow down into the hot water circuit, but no banging or venting but water does not get heated
As a layman I can think of three possibilities
1/ The water heats up too quickly to create circulation current, boils and vents off
2/ There is a Honeywell valve on exit - I replaced the head, and checked the spigot turns, this seems to be OK, and does activate when powered - and tried locked open - seems to be ok but could be blocked
3/ An air block in hot water heating element
What I want is to be able to heat water from boiler without radiators being on....
Should gravity be enough for water heating only
As there are two parallel circuits (rads/pumped+ water/gravity), it's hard to see how they can both exist together...
If you made it this far - thanks for reading - any comments very welcome
Matt