I have a recently installed Evohome controller retrofitted to a pre-existing home heating system. All is working well, except that the HR91 valves cannot fire the boiler unless one or more zone valve is open. Here’s a brief summary of the system.
The problem with this is that the HR92s are associated only with the boiler relay but neither of the heating zone relays (valves). If the two rooms with the wall stats are hot enough (and the cylinder is full of hot water), there’s no way for an HR92 in a much cooler (slower to heat) room to fire the boiler.
Having read other postings on this forum I’m inclined to think I need to get rid of the boiler relay and somehow associate each of the HR92s with the relevant heating zone relay. It sounds simple, but I can’t find documentation of this and don’t know whether the software supports it. Please advise how best to set this up and / or where I can find instructions.
- Evohome controller (2021)
- There are two heating zones and one hot water, each controlled by a motor valve, 3 in total.
- Each motor valve is controlled by a BDR91 relay. There’s also a further BDR91 as a boiler relay (4 in total).
- Each heating zone has a wireless wall stat (T87/Y87) associated which controls the relay and in turn the motor valve for the zone
- Almost all radiators have TRVs, but only 4 have HR92 valve actuators
- A wireless cylinder stat drives the hot water relay and it’s associated valve
- The zone valve contacts are wired in parallel with each other and in series with the boiler relay such that the boiler will only fire if at least one zone valve is open AND the boiler relay is on.
The problem with this is that the HR92s are associated only with the boiler relay but neither of the heating zone relays (valves). If the two rooms with the wall stats are hot enough (and the cylinder is full of hot water), there’s no way for an HR92 in a much cooler (slower to heat) room to fire the boiler.
Having read other postings on this forum I’m inclined to think I need to get rid of the boiler relay and somehow associate each of the HR92s with the relevant heating zone relay. It sounds simple, but I can’t find documentation of this and don’t know whether the software supports it. Please advise how best to set this up and / or where I can find instructions.
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