I have an Ideal concord CXA and its control system wired as per their recommendation for spring return zone valve. There are 4 zones 3 heating and one for hot water controlled by a 4-channel clock and respective thermostats. There is a requirement for one zone valve to be nominated as being open to dissipate the heat during pump overrun. I have the hot water as the nominated zone. The recommended wiring system results in the nominated zone valve being almost permanently open only closing when the system is running and the hot water not calling for heat.
This means that the valve motor is permanently energised when the system is idle as it has a permanent live feed via a relay through which this zone valve is controlled as per recommended wiring diagram. This permanent energising of the valve results in premature failure of the motor typically lasting about 12-15 months. I do not think that this is a good control design. I have raised the issue with Ideal who have not been particularly helpful in commenting on their wiring recommendation. Does anyone have experience of such a control system? . I imagine that similar control systems exist with other boilers. I would have expected that when the pump overrun controlled from the boiler controls timed out the relay would be de-energised causing the valve in turn to close. I do have a solution but do not think at this moment it is particularly elegant and that is to add 2 further relays one powered from the time clock and one via pump over run feed from the boiler wired in an either/or arrangement such that the relay controlling the problematic valve will only operate when asked by the heating controls or by the pump over run. When there is no heat requirement or pump over run requirement then the problematic valve would be powered off when idle.
Any comments would be very welcome.
Thanks
This means that the valve motor is permanently energised when the system is idle as it has a permanent live feed via a relay through which this zone valve is controlled as per recommended wiring diagram. This permanent energising of the valve results in premature failure of the motor typically lasting about 12-15 months. I do not think that this is a good control design. I have raised the issue with Ideal who have not been particularly helpful in commenting on their wiring recommendation. Does anyone have experience of such a control system? . I imagine that similar control systems exist with other boilers. I would have expected that when the pump overrun controlled from the boiler controls timed out the relay would be de-energised causing the valve in turn to close. I do have a solution but do not think at this moment it is particularly elegant and that is to add 2 further relays one powered from the time clock and one via pump over run feed from the boiler wired in an either/or arrangement such that the relay controlling the problematic valve will only operate when asked by the heating controls or by the pump over run. When there is no heat requirement or pump over run requirement then the problematic valve would be powered off when idle.
Any comments would be very welcome.
Thanks
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