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Hi all,
New member here – thanks for the opportunity to post. I recently purchased an Evohome starter kit as I’ve been looking at the system for a while and the price was right. We moved into a 4-bed detached 2 storey house in Feb this year, just before the really cold snap at the start of March. Having previously come from a home with a single zone nest the Evohome setup seemed like the logical progression as heating this house will cost significantly more than our old 3 bed semi.
I spent some time last weekend documenting the boiler and controls wiring in my existing setup, with a view to self-installing the BDR and controller. This proved a bit challenging as I’m not a spark or heating engineer, plus the house has two colours of wiring in it, so it took a bit of time.
I originally posted my query on the Evohome shop forum, but understandably its primarily designed to support shop customers, so reposting here. I’d therefore be very grateful if anyone could offer any opinions on my suggested setup and a couple of related queries.
The system consists of:
Garage
Worcester Bosch Greenstar classic 34Cdi (installed feb ’16)
Sauermann Si82 condensate pump (installed feb 16)
Honeywell Frost stat (installed unknown)
Drayton PTS1 on heating return (installed unknown)
Kitchen (approx. 12m LOS from boiler through block walls)
Invensys (British Gas) UT2 programmer
Hall (leads to kitchen)
Honeywell T40 thermostat
This is how the wiring is presented now: (NB. the neutral wiring on the frost stat isn't complete but i don’t believe its wholly relevant in this case as its fully separate)
I started looking at how the BDR91 would fit into the existing setup. Looking at the Honeywell diagram, with the assistance of some googling to understand How T1 and T2 mapped to LS/LR on my boiler I believe I need to wire Lr and Ls to B and A respectively, as the live to the boiler is already established via the existing wiring into L via the codensate pump. Looking at the existing wiring for the controls I think I could put the BDR91 in the kitchen, utilising the existing 4core and earth wiring there for the programmer. This would cover the existing hole, reduce possible wireless interference and simplify my task.
I would achieve this using the wire denoted (1) in the programmer, connected to A in BDR 91. This already connects to Ls on the boiler. Output (3) from the prog would be jointed to the grey wire going to LR in the “wiring centre”, previously output 3 from the thermo. This effectively cuts out the thermostat from the series. I write wiring centre in quotes because its basically a single gang box with a blanking plate, so not a lot of room, but it would be possible. Here’s the new wiring diagram based on this:
It looks easy enough but that’s based on some assumptions
1. I’ve not fundamentally misunderstood something
2. The web resource for the suggested diagram I’ve used is not wrong
3. The existing wiring beyond the prog/thermo can remain as is and unchanged
4. The PTS and frost stat are completely separate so play no part in this (i'm still researching this)
5. Putting the BDR91 in the kitchen isn’t a major issue (can't see a downside at the mo, apart from its not a visual masterpiece)
Looking at the documentation there’s a recommended minimum gap for the relay from boiler / metal objects, but I can’t see anything about a maximum. There’s also not much on installing it in a garage, but i haven't searched exhaustively. There is plenty on wireless interference, so it stands to reason that closer is better (to a point.) The suggested location of the BDR would be approx. 3m from the evohome controller, so I see no issues with this.
I’d welcome and comments or discussion on the plans and potential pitfalls of the setup. Likewise, any warnings will be heeded – If I’ve made a significant mistake in my reading of this I will step back and let a pro do it, but I have enjoyed the learning to date and would like to see it through if possible. But, safety first.
Thanks again for taking the time to read and the opportunity to draw on the considerable forum expertise.
David
New member here – thanks for the opportunity to post. I recently purchased an Evohome starter kit as I’ve been looking at the system for a while and the price was right. We moved into a 4-bed detached 2 storey house in Feb this year, just before the really cold snap at the start of March. Having previously come from a home with a single zone nest the Evohome setup seemed like the logical progression as heating this house will cost significantly more than our old 3 bed semi.
I spent some time last weekend documenting the boiler and controls wiring in my existing setup, with a view to self-installing the BDR and controller. This proved a bit challenging as I’m not a spark or heating engineer, plus the house has two colours of wiring in it, so it took a bit of time.
I originally posted my query on the Evohome shop forum, but understandably its primarily designed to support shop customers, so reposting here. I’d therefore be very grateful if anyone could offer any opinions on my suggested setup and a couple of related queries.
The system consists of:
Garage
Worcester Bosch Greenstar classic 34Cdi (installed feb ’16)
Sauermann Si82 condensate pump (installed feb 16)
Honeywell Frost stat (installed unknown)
Drayton PTS1 on heating return (installed unknown)
Kitchen (approx. 12m LOS from boiler through block walls)
Invensys (British Gas) UT2 programmer
Hall (leads to kitchen)
Honeywell T40 thermostat
This is how the wiring is presented now: (NB. the neutral wiring on the frost stat isn't complete but i don’t believe its wholly relevant in this case as its fully separate)
I started looking at how the BDR91 would fit into the existing setup. Looking at the Honeywell diagram, with the assistance of some googling to understand How T1 and T2 mapped to LS/LR on my boiler I believe I need to wire Lr and Ls to B and A respectively, as the live to the boiler is already established via the existing wiring into L via the codensate pump. Looking at the existing wiring for the controls I think I could put the BDR91 in the kitchen, utilising the existing 4core and earth wiring there for the programmer. This would cover the existing hole, reduce possible wireless interference and simplify my task.
I would achieve this using the wire denoted (1) in the programmer, connected to A in BDR 91. This already connects to Ls on the boiler. Output (3) from the prog would be jointed to the grey wire going to LR in the “wiring centre”, previously output 3 from the thermo. This effectively cuts out the thermostat from the series. I write wiring centre in quotes because its basically a single gang box with a blanking plate, so not a lot of room, but it would be possible. Here’s the new wiring diagram based on this:
It looks easy enough but that’s based on some assumptions
1. I’ve not fundamentally misunderstood something
2. The web resource for the suggested diagram I’ve used is not wrong
3. The existing wiring beyond the prog/thermo can remain as is and unchanged
4. The PTS and frost stat are completely separate so play no part in this (i'm still researching this)
5. Putting the BDR91 in the kitchen isn’t a major issue (can't see a downside at the mo, apart from its not a visual masterpiece)
Looking at the documentation there’s a recommended minimum gap for the relay from boiler / metal objects, but I can’t see anything about a maximum. There’s also not much on installing it in a garage, but i haven't searched exhaustively. There is plenty on wireless interference, so it stands to reason that closer is better (to a point.) The suggested location of the BDR would be approx. 3m from the evohome controller, so I see no issues with this.
I’d welcome and comments or discussion on the plans and potential pitfalls of the setup. Likewise, any warnings will be heeded – If I’ve made a significant mistake in my reading of this I will step back and let a pro do it, but I have enjoyed the learning to date and would like to see it through if possible. But, safety first.
Thanks again for taking the time to read and the opportunity to draw on the considerable forum expertise.
David
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