We have a traditional vented C/H system with a boiler on the ground floor and an airing cupboard on the first floor containing the hot water cylinder and C/H pump feeding a Honeywell 3-way valve.
I asked a local plumber to fit a new radiator in a ground floor extension, but there was no easy way to access the existing C/H pipe work without emptying an upstairs room and taking up all the flooring, which we didn’t really want to do. Since the boiler was right next to the extension I asked if we could just T-off the two 22mm pipes from the boiler, go through the wall and connect directly to the radiator. OK, he should have known better, but he agreed and made the connections. He did point out that the radiator would be on whenever the hot water was on, but as it was fitted with a TRV, I didn’t think this was a problem.
Of course, it doesn’t work. He later admitted that he is so used to working with combi boilers that have the pump in the boiler, that he forgot that the T-off was upstream of the pump, and the new radiator is effectively short-circuited by the boiler. So the new radiator gets hot when the hot water is on, but cools down when the heating is turned on.
Is there an easy fix? Would fitting an additional C/H pump between the boiler and the T-off to the new radiator, either on the flow or the return, solve the problem? Both pumps would then switch on together and be in series, presumably assisting each other. Or would this cause a surge of water through the vent pipe? I don’t want to solve one problem and cause another.
Any suggestions would be appreciated – apart from rip it all out and start again!
I asked a local plumber to fit a new radiator in a ground floor extension, but there was no easy way to access the existing C/H pipe work without emptying an upstairs room and taking up all the flooring, which we didn’t really want to do. Since the boiler was right next to the extension I asked if we could just T-off the two 22mm pipes from the boiler, go through the wall and connect directly to the radiator. OK, he should have known better, but he agreed and made the connections. He did point out that the radiator would be on whenever the hot water was on, but as it was fitted with a TRV, I didn’t think this was a problem.
Of course, it doesn’t work. He later admitted that he is so used to working with combi boilers that have the pump in the boiler, that he forgot that the T-off was upstream of the pump, and the new radiator is effectively short-circuited by the boiler. So the new radiator gets hot when the hot water is on, but cools down when the heating is turned on.
Is there an easy fix? Would fitting an additional C/H pump between the boiler and the T-off to the new radiator, either on the flow or the return, solve the problem? Both pumps would then switch on together and be in series, presumably assisting each other. Or would this cause a surge of water through the vent pipe? I don’t want to solve one problem and cause another.
Any suggestions would be appreciated – apart from rip it all out and start again!