removed a floor standing potterton yesterday gravity hw pumped htg. the boiler had one flow connection on the old boiler which was fitted with a teed to give gravity hw and then a pump to the rads on the other side of the tee. the rads and hw return pipes tapped into seperate rtn tappings on the boiler with the pump on the htg rtn.fitted new glowworm hxi and teed the rads and hw rtn together to new boiler put flow from boiler to pump then to s plan to rads and hw circs.the old system had a heat leak rad in the bathroom but unable to change this as floor laminated and ply under that.new boiler works fine on htg.on hw with the heat leak on the rad gets very hot but very poor heat to cylinder- turned heat leak off and the boiler oveheats no circuit . zone valves ok auto air vent to cyl no air traced pipes from cylinder in loft which dropped down bathroom wall boxed in and tiled and then into kitchen below . i thought anti gravity valve but these are only normaly on th eheating circuit ? . anyone got any ideas - just left there i want to cry.
Think you are right thinking a non return valve fitted on the circuit somewhere,the old pump should have been on the return pipe work,no? pulling back to boiler not flow
what was the water quality like on drain down? have had a blocked coil on 1" feeds before rare but might be worth checking.
has there been a problem in the past with the heat leak not getting hot and some genius has fitted a restriction to the cylinder out of sight to force it to the rad?
Think you are right thinking a non return valve fitted on the circuit somewhere,the old pump should have been on the return pipe work,no? pulling back to boiler not flow
pump was on rtn pulling back now on flow with splan.only thing that puzzled me was when testing old boiler checked what pipe got hot first on circs and assumed this was flow .when in the loft the bottom coil pipe gets warm not the top and the combined fed and vent is on this bottom pipe - going to swap pipes at new boiler end to see if its due to the combined vent on this or a non rtn valve on the pipe.
i know this isnt any help but we will not reuse gravity pipework that we cant inspect completely on to fully pumped sytems weve had to much trouble with them in the past, did it circulate when you powerflushed ?
what was the water quality like on drain down? have had a blocked coil on 1" feeds before rare but might be worth checking.
has there been a problem in the past with the heat leak not getting hot and some genius has fitted a restriction to the cylinder out of sight to force it to the rad?
removed fittings from coil and blew through all clear . on pipework i can see no restrictor checking tomorrow by reversing pipes if that does not work then going to have to trace each end and put mains water hose through to check flow
Hi ant, you've mentioned two pumps in your op, one on the flow and another on the return .. could you clarify please? Did it have one or two pumps fitted?
Hi ant, you've mentioned two pumps in your op, one on the flow and another on the return .. could you clarify please? Did it have one or two pumps fitted?
old boiler had pump on rtn from rads . new boiler piped as s plan with new pump now on flow as it should be only thing that is not as i would like is combined feed and vent on the rtn from cyl in kitchenas not possible to get one to under pump. cyl in loft boiler in kitchen.
Sounds strange to have one flow teed and two returns? Just trying to get a picture of the installation; I take it the forth tapping (flow) wasn't used yeh? Heating circuit working fine yeh Ant? Only issue is with the hot water circuit! Where the pipes differnet sizes or all the same?
Sounds strange to have one flow teed and two returns? Just trying to get a picture of the installation; I take it the forth tapping (flow) wasn't used yeh? Heating circuit working fine yeh Ant? Only issue is with the hot water circuit! Where the pipes differnet sizes or all the same?
sorry steve old boiler which i removed floor standing potterton had the flow tapping out of the back then split to feed circs and pipe to rads. the circs rtn come back to the boiler bottom tapping the rads rtn had pump fitted and piped to smaller tapping on boiler. fitted new glowworm hxi today and re piped - joined circs rtn and rads rtn to new boiler rtn . flow from new boiler fitted pump then zone valve to rads flow pipe and zone valve to hw circ flow pipe standard s plan realy. when heating is on rads work and boiler fine . hw only on and the old heat leak rad i had to leave piped as it was piped under laminated floor gets red hot but the pipes to the cyl only luke warm - turn this heat leak off and the boiler overheats due to no flow .think there may be non rtn valve on one of the hw circs.hw circ pipes rise from kitchen through bathroom to loft across loft to cyl all boxed in and tiled through bathroom - these pipes must be teed into under bathroom floor to feedd heat leak rad but laminate flooring laid on ply covered floorboards.done combined feed and vent on the circ rtn in loft
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