My central heating system consists of a baxi condensing boiler, which has one flow and one return pipe, a pump, a 3-way motorised valve, a programmer and a cylinder thermostat. All these components appear to be working fine.
However, the pipework has been altered recently and something strange is happening. Basically, when the system is switched to hot water only, the return flow from the cylinder not only goes back to the boiler, but also flows up the return pipe to the central heating radiators. The effect of course is that the radiators heat up.
I have checked the motorised valve and this is working fine. When the system is switched to hot water only, the flow pipe from the 3-way valve to the radiators remains cold, which is what you would expect of course.
I suspect that this is a pipework problem. Basically, when this type of system is working correctly and hot water only is selected, normally what stops the water from flowing back up the return pipe to the radiators, at the point where the return from the cylinder and the radiators join? As I understand it, there isn't a valve at this point.
If I can understand this, hopefully I will be able to figure out what is wrong with the plumbing in my system.
Any advice will be gratefully received.
However, the pipework has been altered recently and something strange is happening. Basically, when the system is switched to hot water only, the return flow from the cylinder not only goes back to the boiler, but also flows up the return pipe to the central heating radiators. The effect of course is that the radiators heat up.
I have checked the motorised valve and this is working fine. When the system is switched to hot water only, the flow pipe from the 3-way valve to the radiators remains cold, which is what you would expect of course.
I suspect that this is a pipework problem. Basically, when this type of system is working correctly and hot water only is selected, normally what stops the water from flowing back up the return pipe to the radiators, at the point where the return from the cylinder and the radiators join? As I understand it, there isn't a valve at this point.
If I can understand this, hopefully I will be able to figure out what is wrong with the plumbing in my system.
Any advice will be gratefully received.