The Efficient Home Forum

adamski88 wrote: Thu Apr 18, 2024 2:35 pmCould I ask why I need to say 'NONE' under 'BOILER CONTROL'? Just for my understanding

Because you don't have a combi boiler.

I have just made the video available. I didn't realise the video had been made private.

Richard wrote: Thu Apr 18, 2024 2:53 pm

adamski88 wrote: Thu Apr 18, 2024 2:35 pmCould I ask why I need to say 'NONE' under 'BOILER CONTROL'? Just for my understanding

Because you don't have a combi boiler.

I have just made the video available. I didn't realise the video had been made private.

Thanks, can see it now.

In regards to the boiler control, i saw this in some of the resideo documentation:

I'm fairly sure the BDR91 is wired straight to the boiler?

Having just watched the youtube video, I only have one BDR91 (in place of where the old thermostat controls were located)

Does this help with the understand of my system? Apologies I can't elaborate further on the actual plumbing setup.

adamski88 wrote: Thu Apr 18, 2024 2:58 pmThanks, can see it now.

In regards to the boiler control, i saw this in some of the resideo documentation:

I'm fairly sure the BDR91 is wired straight to the boiler?

Those instructions are for a combi boiler where you would wire the BDR91 straight to the boiler. With an S or a Y Plan system you would normally wire the BDR91's directly (sometimes indirectly if you wire one of them in the old thermostat position) to the wiring centre. Having a 3rd BDR91 is quite rare, and this is the only time you would have a 'BOILER RELAY' with a system with a hot water cylinder.

If you don't have a combi boiler (i.e. you have a hot water cylinder) and you have only 2x BDR91's and a CS92A then the below schematic is the one to follow. I also wrote this help guide which may or may not help you - https://thesmartthermostatshop.co.uk/ev ... elp-guide/

adamski88 wrote: Thu Apr 18, 2024 3:06 pm Having just watched the youtube video, I only have one BDR91 (in place of where the old thermostat controls were located)

Does this help with the understand of my system? Apologies I can't elaborate further on the actual plumbing setup.

If you have a hot water cylinder you must have two?

Richard wrote: Thu Apr 18, 2024 3:14 pm

adamski88 wrote: Thu Apr 18, 2024 3:06 pm Having just watched the youtube video, I only have one BDR91 (in place of where the old thermostat controls were located)

Does this help with the understand of my system? Apologies I can't elaborate further on the actual plumbing setup.

If you have a hot water cylinder you must have two?

Theres definitely only 1, I bought everything personally. The BDR91 got fitted in the kitchen on the same wiring as where the old thermostat was.

I live in Northern Ireland, could things be done a little differently here maybe?

Just the BDR91 in the kitchen and the CS92 beside the hot water tank

If you only have 1x BDR91, I don't fully understand how this can be working (properly)? What boiler do you have?

1x BDR91 comes with the evohome controller (https://thesmartthermostatshop.co.uk/pr ... p921r3100/) and 1x BDR91 comes with the CS92A (https://thesmartthermostatshop.co.uk/pr ... atf500dhw/) so you should have 2?

This is why images help...

Richard wrote: Thu Apr 18, 2024 3:47 pm If you only have 1x BDR91, I don't fully understand how this can be working (properly)? What boiler do you have?

1x BDR91 comes with the evohome controller (https://thesmartthermostatshop.co.uk/pr ... p921r3100/) and 1x BDR91 comes with the CS92A (https://thesmartthermostatshop.co.uk/pr ... atf500dhw/) so you should have 2?

This is why images help...

O dear. This is what happens when your trying to work and sort your heating at the same time

I do apologise! I totally forgot BDR91 was included inside the hot water kit. I've had a hunt around and there is indeed another relay under the stairs :/

So are we thinking the heating engineer just set it up incorrectly then?

To give you a (hopefully!) complete picture:

Initially, the house had a really ancient theromostat control, one of those ones where you push the wee pins in to set the times! Beides that, there was 1 button, on and off.

We then had a switch on the wall by the stairs, if this switch was on and the heating was on, we got hot water. If it was off while the heating was on, no hot water.

The BDR91 (the newly found second one!) is fitted directly on the other side of this wall where the original hot water on/off switch it (im assuming its where this BDR91 is getting its power from).

How does this new information (sorry again!) tie in? Is the original BDR91 likely connected to the boiler (the one which replaced the old thermostat), and if so, does this change anything?

I really appreciate all your help!

Spoke to the plumber who installed the system, he said the gist of the system is "oil fired boiler with a 2 port motorised valve conntected to the relay box for hot water control of the cylinder"

asked him if the boiler control should be set to none and he said no,it should be set to wireless relay box

adamski88 wrote: Thu Apr 18, 2024 5:02 pm Spoke to the plumber who installed the system, he said the gist of the system is "oil fired boiler with a 2 port motorised valve conntected to the relay box for hot water control of the cylinder"

asked him if the boiler control should be set to none and he said no,it should be set to wireless relay box

Problem is, half the installers out there are not evohome trained and don't fully understand the applications correctly.

There is only a few ways to fit evohome within its operation hierarchy and what he is saying isn't one of them.

Glad you found your second BDR91 btw.