Completely understand where you are coming from. Depending upon what they are doing, one option is to use the hot water override (assuming you have a DHW tank and it is not up to temperature).
The concept of smart zones is something I really like and glitches aside Evohome is great.
One scenario it does cause issues though is when I have a plumber or heating engineer here. They invariably want to "knock the boiler on/off" and Evohome always causes a bit of confusion when I explain "hang on I'll set a couple of rooms to 30C, but you'll need to wait a couple of minutes".
Last week we had our CH system flushed and he needed to make sure all radiators were open so I showed him how to set overrides but it's a bit of a faff. It's not like you can just remove all the TRV heads and manually open the valves because then there is nothing demanding heat from the boiler.
I've had this with at least 3 different engineers so I imagine others have too. Maybe I've missed some obvious tricks or a good way to explain it - anyone got some good tips from their own experiences?
Completely understand where you are coming from. Depending upon what they are doing, one option is to use the hot water override (assuming you have a DHW tank and it is not up to temperature).
I would just go for the set-a-zone-to-30 approach, but you could also just press the override button on the heating BDR91?
Why not just switch the power off to the boiler from the main switch for a simple off? I am lucky as my Evohome system does not need/use a BDR91 and when servicing time comes the engineer simply uses the main on/off switch and turns the tap on to fire the boiler up (its a combi). I do though turn one TVR up high whilst he is here to trigger the CH part and pump if needed.
Last edited by G4RHL; 26th May 2022 at 11:25 AM.
Pushing the button on the BDR unit will instantly turn the kettle on. Of course if no zone is requesting it will shut off again after a few minutes. As for opening all radiators, taking off the TRV heads is a pretty sound idea and something you can do before the guy (or girl) gets in. This effectively converts your system to a single zone classic setup.
Even on an traditional system with mechanical thermostats and timers you'd still need to switch the timer into manual override and turn up the thermostat to make the boiler fire up. With modern/smart systems it's still the same basic principle so if an engineer has trouble working out how to do that then it's probably time to find another engineer....![]()
I think that when 3 or 4 separate experienced engineers all complain it's making their life complicated, I'll trust their professional opinion.
I'm not asking if you think it's complicated for the plumber, I'm asking for ways to make it simpler if they are not familiar with smart heating systems. Round here at least they are not common at all. I haven't met anyone else who has one.
A solution that works for me is to create a new dummy zone using the evohome controller itself as the zone temperature sensor, and the type set to "Zone Valve". If you complete this *without* adding a zone valve (i.e. DO NOT double-bind the BDR91), then that zone will directly turn the heating on/off via the main BDR91 whenever it demands heat. Possibly a quirk rather than an intentional feature, but it works for me. The setpoints for that zone are set really low, to ensure that it never comes on automatically because of the dummy zone temperature. I can fire the boiler up instantly by raising the setpoint of this dummy zone; much faster than setting one of the HR91/HR92 zones, which have to wait for that to finish opening before the BDR91 is turned on.
Just be aware of whether or not your system has/needs a bypass, because in this configuration, the BDR91 will turn the boiler on even if all radiator HR91/HR92 are closed. I have a regular TRV head in the bathroom which is usually open anyway, plus my Vaillant boiler has an internal bypass, so it isn't a problem for me.