Why do my rads run part-time only?

[Andrew N]

I replaced my conventional boiler with a condensing variety. The rads in my bathroom & en-suite run off the HW circuit (vice CH circuit) and used to keep the rooms heated for the duration of the run time of the HW cct. Now, at best, they heat up when the HW system fires up, then cut off within about 30 mins.

Plumber who fitted the boiler says I have to live with it.

I note that I can now hear water running through the CH rads in the house, and wonder if the pump speed has been increased & if this is the problem.

Anyone out there had similar experience and/or can offer advice?

 

[D_Hailsham]

Make and model of new boiler, please.

 

[namsag]

You probably had gravity hot water circuit before so rads would have stayed on. Now you have an efficient system that has electrical valves on HWcircuit and close when cylinder is satisfied usually around 30 mins...Only way is to alter pipework if possible so rads get put into the heating circuit

 

[Andrew N]

You probably had gravity hot water circuit before so rads would have stayed on. Now you have an efficient system that has electrical valves on HWcircuit and close when cylinder is satisfied usually around 30 mins...Only way is to alter pipework if possible so rads get put into the heating circuit

System is fully pumped, only change was the boiler - from an old 10,000BTU unit to a Baxi Solo HE30. Could it be that the pump speed had to be increased to cope with a condensing boiler?

Many thanks for your interest,

Andrew N

 

[Andrew N]

Make and model of new boiler, please.

Baxi Solo 30HE (or HE30). System is fully pumped with electrically-operated zone valves for HW & CH ccts.