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Delaying valve closure

Posted: 11 Nov 2019, 11:22
by Aironide
Good morning,
my system consists of 5 valves and a thermostat that controls the ignition and shutdown of the boiler. When the thermostat reaches the set temperature, the boiler switches off and at the same time the valves close. The problem is that the boiler pump continues to run for a few minutes in order to exploit the hot water in the circuit again, but the valves on the radiators have already closed thus, preventing the circulation of the remaining hot water. Is it possible to delay the closing of the valves and not to make them close when the thermostat turns off the boiler?
Thanks in advance.

Re: Delaying valve closure

Posted: 23 Nov 2019, 11:06
by Aironide
No way?

Re: Delaying valve closure

Posted: 27 Nov 2019, 03:00
by PhilHornby
Aironide wrote:
11 Nov 2019, 11:22
When the thermostat reaches the set temperature, the boiler switches off and at the same time the valves close.
I thought it was the fact that all valves are reporting 'fully closed', that causes the boiler to be powered off? (Though I'm curious as to whether the Room Stat. has to reach its Setpoint as well (or instead?))
And he wrote: The problem is that the boiler pump continues to run for a few minutes in order to exploit the hot water in the circuit again, but the valves on the radiators have already closed thus, preventing the circulation of the remaining hot water. Is it possible to delay the closing of the valves and not to make them close when the thermostat turns off the boiler?
There would need to be an electrical connection between the Pump and the Netatmo Relay, in order for the valves to be delayed in their closing until the pump stops. Even then, the pump could be running because the Hot Water is being heated. A further complication, is that motorised valves in the system will potentially change position when the 'Boiler-on' signal is removed (definitely true in the case of two port valves). In this case, residual heat in the system can't be sent to the radiators anyway.

As things stand, any residual heat should be dispersed through either an automatic bypass valve, or an 'always-on' radiator (probably in a bathroom).

Re: Delaying valve closure

Posted: 04 Dec 2019, 14:30
by box
If temperature has been reached at the valve and nothing else is calling for heat, it makes more sense that the valves just instruct the boiler to turn off, and not close the valve? If the boiler comes on again at a later point and the room with the valve(s) are already warm, at that point the valve should shut. Might save a few opening/closing events too so saves battery.