I now see why the pump is presently located (rather awkwardly) in the boiler casing!...the expansion tank water level is presently 2.48m above the pump...if I put the pump in the loft it reduces down to 1.28m - clearly not enough. I can't really move the expansion tank any higher and there is not much area around the boiler siting for a pump to be fitted at a lower level.
I have searched for a conventional boiler with an integral pump...Keston Celsius 25...but that requires an expansion tank height from the top of boiler to its (tank's) bottom of 2.75m minimum, plus it would require the vent pipe to be relocated off the flow pipe to the return.
Are there any other good quality conventional boilers with integral pumps without such demanding configuration requirements?...failing all, I may have to locate the pump below the floor in a room on one of the leg runs...I don't know if this is acceptable as many boiler schematics show it to be placed in the run from the boiler to the vent pipe on the flow line - Any advice much appreciated.
I have searched for a conventional boiler with an integral pump...Keston Celsius 25...but that requires an expansion tank height from the top of boiler to its (tank's) bottom of 2.75m minimum, plus it would require the vent pipe to be relocated off the flow pipe to the return.
Are there any other good quality conventional boilers with integral pumps without such demanding configuration requirements?...failing all, I may have to locate the pump below the floor in a room on one of the leg runs...I don't know if this is acceptable as many boiler schematics show it to be placed in the run from the boiler to the vent pipe on the flow line - Any advice much appreciated.