Qiuet
- Thread starter PEDANTICVINDICTIVEMAN
- Start date
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Worse. I hardly dare admit it. Shall we say boiler - vent - feed - pump - bypass - valves.
Perhaps not a non-compliance but might explain the pumping over. Currently trying to work out a solution that doesn't involve demolishing the house.
Perhaps not a non-compliance but might explain the pumping over. Currently trying to work out a solution that doesn't involve demolishing the house.
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Are you serious? Where would expansion be taken up - in the feed tank? What happens if the system boils?
What we have (starting from boiler flow) is boiler - pump - auto bypass - MV - vent - HW cylinder - feed - boiler. Note vent is on flow side of cylinder, feed on return, and both of them connect close to cylinder. Predictably, pumping-over only occurs when HW is called. When HW valve is closed it effectively shields pump from vent.
Rads are on a parallel unvented circuit.
Pipework to cylinder is mostly 28mm (hangover from its gravity fed days) with some 22mm. One straight leg of 15mm pipe about 10ft long connects cylinder to F&E tank in loft directly above it. This would be relatively easy to replace. But could we cheat further and use the existing 22mm vent pipe as a feed, simply moving it to bottom of expansion tank and eliminating the current 15mm feed? This would have it feeding to the flow side of the cylinder with 28/22mm all the way.
Why does it need to be 22mm anyway?
Am I stupid or what?
What we have (starting from boiler flow) is boiler - pump - auto bypass - MV - vent - HW cylinder - feed - boiler. Note vent is on flow side of cylinder, feed on return, and both of them connect close to cylinder. Predictably, pumping-over only occurs when HW is called. When HW valve is closed it effectively shields pump from vent.
Rads are on a parallel unvented circuit.
Pipework to cylinder is mostly 28mm (hangover from its gravity fed days) with some 22mm. One straight leg of 15mm pipe about 10ft long connects cylinder to F&E tank in loft directly above it. This would be relatively easy to replace. But could we cheat further and use the existing 22mm vent pipe as a feed, simply moving it to bottom of expansion tank and eliminating the current 15mm feed? This would have it feeding to the flow side of the cylinder with 28/22mm all the way.
Why does it need to be 22mm anyway?
Am I stupid or what?
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