Hi all,
I'm new here, so please go easy on me!
Its a fairly long one, so please bear with me...
I've got a fairly simple Evohome system, comprising a Base Pack, Hot Water Kit, Remote Gateway and 4 Radiator Valve Zones. It is connected to a Y-plan system, and my hot water cylinder is a vented type. The boiler is hard wired to the mid-position valve in the wiring centre.
I have installed it and cleared all binding on the BDR91s and factory reset the Controller. After that, I have set the 2 BDR91s as hot water and heating zone valves only - there is no boiler relay configured. Everything seems to be working perfectly from that point of view, the boiler interlocks work correctly and I can have heating only, dhw only and heating/dhw combined.
I understand that my configuration means that in the Installation/Parameter Settings menu, I don't get the Cycle Rate and Minimum On Time options, because I don't have a Boiler Relay configured. I was surprised to find that I also don't have the Fail Safe options to configure - is that correct? Do those options only apply to a Boiler Relay?
I am a little concerned about how safe the Hot Water control is via wireless only. In fact, last night I set the hot water on, so that the dhw relay called the dhw valve and fired the boiler, then took the batteries out of the hot water sensor by my cylinder for 30 minutes o test the safety features (was as long as I dared!). I was alarmed to find that the dhw relay carried-on calling for heat the whole time, before I bottled-out and put the batteries back in.
My question is, would the dhw relay have switched off at some point when the Evohome Controller finally decided that it had lost communication with the hot water temperature sensor, or would the water have continued to heat the dhw to a dangerous level? Does this relate to a missing Fail Safe menu on my Controller?
I am also considering refitting the old thermostat to the dhw cylinder, setting the temperature on it high and connecting the dhw call contacts in series with the output to the boiler from my wiring centre. That way, the Evohome would be controlling the dhw, but the old stat would act as an overheat stat and prevent the boiler firing at all. I know a back-up thermostat is not strictly required on a vented cylinder, but I'd like it as safe as possible.
Thank you in advance for your help.
Thepook
I'm new here, so please go easy on me!
Its a fairly long one, so please bear with me...
I've got a fairly simple Evohome system, comprising a Base Pack, Hot Water Kit, Remote Gateway and 4 Radiator Valve Zones. It is connected to a Y-plan system, and my hot water cylinder is a vented type. The boiler is hard wired to the mid-position valve in the wiring centre.
I have installed it and cleared all binding on the BDR91s and factory reset the Controller. After that, I have set the 2 BDR91s as hot water and heating zone valves only - there is no boiler relay configured. Everything seems to be working perfectly from that point of view, the boiler interlocks work correctly and I can have heating only, dhw only and heating/dhw combined.
I understand that my configuration means that in the Installation/Parameter Settings menu, I don't get the Cycle Rate and Minimum On Time options, because I don't have a Boiler Relay configured. I was surprised to find that I also don't have the Fail Safe options to configure - is that correct? Do those options only apply to a Boiler Relay?
I am a little concerned about how safe the Hot Water control is via wireless only. In fact, last night I set the hot water on, so that the dhw relay called the dhw valve and fired the boiler, then took the batteries out of the hot water sensor by my cylinder for 30 minutes o test the safety features (was as long as I dared!). I was alarmed to find that the dhw relay carried-on calling for heat the whole time, before I bottled-out and put the batteries back in.
My question is, would the dhw relay have switched off at some point when the Evohome Controller finally decided that it had lost communication with the hot water temperature sensor, or would the water have continued to heat the dhw to a dangerous level? Does this relate to a missing Fail Safe menu on my Controller?
I am also considering refitting the old thermostat to the dhw cylinder, setting the temperature on it high and connecting the dhw call contacts in series with the output to the boiler from my wiring centre. That way, the Evohome would be controlling the dhw, but the old stat would act as an overheat stat and prevent the boiler firing at all. I know a back-up thermostat is not strictly required on a vented cylinder, but I'd like it as safe as possible.
Thank you in advance for your help.
Thepook
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