Short cycling and zone valve control
I have digested everyone's earlier suggestions and advice re my short cycling/gradient limitation and plan doing the following:
1. Disconnect upstairs CH zone valve cable wiring from wiring centre (presently wired in parallel to downstairs CH zone valve) and re-connect to Grundfos pump.
Only connecting brown (to trigger open valve) plus N + E.
Leave isolated Orange and Grey (prevents re-trigger of boiler).
Above should keep pump on and upstairs valve open whilst boiler is sending pump overrun live signal. Happy letting towel rails and landing all with manual TRVs run.
This then prevents the gradient limitation from tripping with rising flow temperature.
2. Boiler control is maintained by BDR91 signal to downstairs zone valve and switch to Orange.
I think above is a variation of a DBMandrake suggestion.
I have one question if someone could advise:
- the power rating as specified for a Honeywell 4043 zone valve is 2.2 amps and the Grundfos pump is .44 amp. Does this total of 2.64 amps risk anything when the zone valve is wired to the pump??
Many thanks
Ref previous posts by Edinburgh2000, DBMandrake and others
1. Disconnect upstairs CH zone valve cable wiring from wiring centre (presently wired in parallel to downstairs CH zone valve) and re-connect to Grundfos pump.
Only connecting brown (to trigger open valve) plus N + E.
Leave isolated Orange and Grey (prevents re-trigger of boiler).
Above should keep pump on and upstairs valve open whilst boiler is sending pump overrun live signal. Happy letting towel rails and landing all with manual TRVs run.
This then prevents the gradient limitation from tripping with rising flow temperature.
2. Boiler control is maintained by BDR91 signal to downstairs zone valve and switch to Orange.
I think above is a variation of a DBMandrake suggestion.
I have one question if someone could advise:
- the power rating as specified for a Honeywell 4043 zone valve is 2.2 amps and the Grundfos pump is .44 amp. Does this total of 2.64 amps risk anything when the zone valve is wired to the pump??
Many thanks
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