Going smart control on existing Glowworm / ESi setup

[Adrian E]

Hi all

Been reading (a lot!) about different options for smart control of central heating systems, and trying to narrow down what my choices are, and any specific points with the existing configuration that impacts on choice.

Based on reading to date, I think either the Honeywell Evohome or Drayton Wiser are the way to go.

Our setup is as follows:

Glowworm 18hx Flexicom boiler (this lives in the integral garage)

ESI ES3247 3 channel programmer (in the utility room, on the back of the garage)
We have 2 heating circuits (house is 2015 build) split by floor, plus hot water tank in the upstairs cupboard along with the various pressure vessels, a wiring hub of some sort, and a couple of motorised valves for the heating circuits.

The heating circuits are controlled by wired ESI room thermostats (downstairs is in the hallway, upstairs in the master bedroom) so in those 2 locations we don't have TRVs. Every other radiator (13!) has a TRV fitted.

My understanding is that the Honeywell will cope perfectly well with this setup, but at a chunky price point if I replace TRVs all over the house. I'm less sure about the Wiser (although prefer the look of it and it appears to be based on newer tech) as I can't find any information about how it would work with our hot water system. The hot water tank has a thermostat on it that looks extremely similar to the ESI room thermostats, and I'm assuming that stat on the tank isn't going to talk to the Wiser interface? Or am I over-thinking this bit? I can set the temperature on the thermostat on the tank, which is clearly only sending a signal to the boiler to heat the hot water if it's below that setting AND the controller is set to fire the hot water supply. There's also a temperature control on the boiler itself, which I'm assuming is the supply temperature to the radiators for central heating circuits?

If more info is needed I can investigate and/or post pictures, but that's probably too much info in one post as a starting point anyway!

Help!

 

[CBW]

I think you’d need this for the wiser https://www.draytoncontrols.co.uk/product/wiser-thermostat-kit-3-0

 

[Adrian E]

Thanks - that's the basic system I was assuming I'd need Interestingly the datasheet at your link is the first place I've seen any mention at all of hot water control, and that states that it will use the existing cylinder thermostat to control hot water temperature. If that's the case, it at least explains how it does that. My boiler doesn't support opentherm so at least I don't have to think about that side of it.

Think I need to investigate the wiring box in the airing cupboard to see what's marked in there. I'm expecting to need to remove some power feeds to the existing room thermostats as the other necessary step to remove traces of the old system. The programmer instructions suggest the wiring is configured differently to the Wiser, so best pull that off as well to see if I can make sense of it!

 

[Adrian E]

OK, been doing some more research of my existing setup and figuring out what needs to change if I go for the Wiser setup, just to make sure there's no trip ups at the point I'm committed to disconnecting things!

So the layout of the system is standard S config 3 valves:

(Please excuse the mess under the pump from when the pump seals failed!)

The 2 heating circuit room thermostats have connections to N/O and COM only (both have another wire terminated in a choc block, which I'm assuming is an earth)

One has x2 brown wires, the other has 1 brown and 1 black (same terminals used).

Rather than a 'traditional' wiring centre, the one we have is one of the ESI PCB ones:

So how does one go about removing the wired thermostats from the equation? I'd like to leave the wiring in place in case we move and want to put the old setup back in (plus it's all hidden behind plasterboard and will no doubt be a total pain in the arse to remove!) but unsure whether I simply need to disconnect the single wire attached to each of the 'room stat' headers and suitably insulate, or if I also then need to join the N/O and COM wires where the room thermostats are removed (noting the backplate says they're 230v), or if there's something more substantial required in terms of completing the circuits?

I've also had the programmer off the wall and the wiring to that looks to be a bit different to the Wiser (although not horrifically so). The ESI 3 channel programmer has connections to terminals 3 (HW on), 4 (CH1 on) and 6 (CH2 on) whereas Wiser suggests heating CH1 and CH2 go to terminals 1 and 3, and HW to terminal 2, so working on the basis those just need moving around to suit.

Programmer:



Existing connections:



Wiser wiring diagram:

Hopefully I've not missing anything out, and grateful for any advice (especially if I've fundamentally misunderstood something!)

Cheers

Adrian

 

[damobrowny]

Hi Adrian, did you ever work this out. I have exactly the same system and setup. I've installed a Drayton wiser 3 channel system but the heating is not working as desired. Although I've turned the old hard wired thermostats up to full they come on as scheduled and then go off after 10mins.

 

[ianmcd]

you need to start a fresh post, it is against site rules to hi-jack an existing post and makes it really complicated trying to give the correct advise, start your own post and add as many pics of existng wiring etc

 

[Adrian E]

Just to close off this thread, I did complete the installation in November 2021 and now have Wiser installed using their Kit 3, with 12 iTRVs and having left 4 original TRVs in place in the bathrooms and a walk in wardrobe.

The plumbing install was straightforward enough - a couple of new TRV valve bodies for the rooms where the existing room thermostats were located to make them controllable was all that was needed.

The ESI controls backplate has more pins than the 'industry standard' so had to change the backplate. The wiring changes pictured above sorted out the move from ESI to Wiser, so just a case of reading what wire in the back of the ESI backplate needed to move to where on the Wiser.

My old wired room thermostats basically just had a signal loop back to the wiring centre, which doesn't meet ESI's installation requirements. I took a punt that joining the wires in the wall behind the old room thermostats would deal with those, which proved to be correct. I'm sure if I'd wanted to I could've done something at the wiring centre instead, but since I needed to make good the plasterboard anyway it seemed logical to make the changes there.

To get signal around all the iTRVs I needed 3 smart plugs, which act as range extenders to the Zigbee network that Wiser creates. I probably could've got away with 2 in the end, but 3 means I've never had connectivity issues after initial commissioning.

Overall been really pleased with Wiser - it does what we wanted it to do, in allowing heat for rooms that would otherwise have heating shut down due to the positioning of the old wired room stats, meaning they never properly warmed up. The Eco feature means it shuts the system down earlier if it can maintain temperature to the next set point programmed. Word of caution about using 'Comfort' mode, as it really ramps up your gas bill! We found in the first winter it would kick the heating on at 4.30 to bring bedrooms up to temperature by 6am scheduled start. As well as being noisy we noticed our costs ramped up, so that feature is now switched off. Away mode is good enough for us when we're all out, which isn't that often as I work from home full time, so the lack of geofencing isn't a massive problem.

 

[Mister Banks]

I also have Wiser but a 2 channel with 6 iTRV's, 2 room thermostats and 1 smart plug. Its a good system but does need some tweaking to get it working well.