When a CH pump is stopped, what resistance does the pump rotor offer to water flow??
The reason I ask is that I have an oil central heating system in a boat and want to use heat from the generator cooling to heat the CH system via a tubular heat exchanger. The system layout is such that I can easily do it on existing CH system pipes, with a second pump that runs when the generator is running, but I do not want the post heat exchanger hot water taking the route of least resistance round the boiler. I am hoping that the stationary CH system pump rotor will offer a high resistance. This is fitted at the supply end of the CH boiler. I could fit a solenoid valve to stop the water going where I do not want it to go, but would prefer not to.