Combi boiler with Drayton LP20RF & DIGISTAT+RF - upgrading to programmable or smart thermostat

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/82158488#Comment_82158488

Good decision with the CT200, I think.

I'm surprised the heating stayed on with the LP20RF disconnected - I would have expected it to have gorn off. But, not an issue - the answer is 'out there'.

The LP20RF can be refitted once the ribbon cable is disconnected, so you don;t need a blanking cover.

And, yes, it should be as simple as the 2-wire connection betwixt the orange EMS connector and the CT200's 'plinth'.

What I do not know is whether any other terminal in the boiler needs to be disconnected or by-passed to allow the CT200 to take over, or what the DHW setting defaults to with the Drayton removed; you ideally do not want 'pre-heat' activated - it's a waste of gas, and a large increase in boiler wear.

So, for the answers to these points, ask WB. I think I've suggested that before, once or thrice. 🙃

Where will you mount the CT200?

grumpy_codger

https://forums.moneysavingexpert.com/discussion/comment/82160019#Comment_82160019

The LP20RF can be refitted once the ribbon cable is disconnected, so you don;t need a blanking cover.

ATM I connected it back and hope it will work like @silvercar suggested.

What I do not know is whether any other terminal in the boiler needs to be disconnected or by-passed to allow the CT200 to take over, or what the DHW setting defaults to with the Drayton removed; you ideally do not want 'pre-heat' activated - it's a waste of gas, and a large increase in boiler wea

Switched to 'eco' already

So, for the answers to these points, ask WB. I think I've suggested that before, once or thrice.

I will if it doesn't work.

Where will you mount the CT200?

Landing or corridor on the first floor, near the boiler that is in the former HW cylinder cupboard. There are no any radiators there, but the doors are always open and plenty of hot air goes up from the ground floor.

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/82160059#Comment_82160059

Where is the DHW Eco switch? Not on the Drayton LP20RF?

I don't know whether the CT200 will electronically 'override' a still-connected LP20RF, but I wouldn't bet on it. Tbh, I would ask WB before starting this.

If it's easy to do, I would personally always choose the main living area to house the controller - that's the room where the chosen stable temp matters most, and it is not beholden to the rest of the house.

grumpy_codger

Where is the DHW Eco switch? Not on the Drayton LP20RF?

It's the boiler own control - see the photo in my second post here.

If it's easy to do, I would personally always choose the main living area to house the controller - that's the room where the chosen stable temp matters most, and it is not beholden to the rest of the house.

The living room is too far away and we don't spend much time there. And I'm used to the fact that with heating ON the difference between ground floor and first floor is stable and predictable - about 2C. I'll see how it goes and can move the thermostate later if this is really needed.

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/82160140#Comment_82160140

Cool - sounds good.

Please update when it's done - I suspect (& hope) you'll like it.

grumpy_codger

https://forums.moneysavingexpert.com/discussion/comment/82160348#Comment_82160348

So far so good. Bought new for £125 on Ebay, and there were cheaper options.

For the record: what I don't like is that geofencing is sort of rudimentary - the radius is fixed and very small, but I knew this before buying.

And I disconnected the existing Dryton like you suggested. This made more sense and I didn't have time to experiment.

WIAWSNB

So, it's working?!

Nice job. 😁

FreeBear

For the record: what I don't like is that geofencing is sort of rudimentary - the radius is fixed and very small

Geofencing often relies on a bluetooth connection within range. With most phones, this gives you up to around 10m range.

grumpy_codger

With my former Honeywell it relied on the real location and I could set the radius to any distance, including miles. I don't think this Bosch has Bluetooth, and the app does require 'Location' to be ON for this to work.

WIAWSNB

Seems promising other than that, tho'?

I presume your boiler display will give CH delivery water temperature readings when it's running? It'll be interesting to see if you notice any difference in behaviour - boiler running for longer and cooler once up to temp, and things like that. Rads being kept at a mid-temp rather than cycling on and off.

What does the geofencing do? Turn down the CH if you leave home? Turn it back up as you return?

My Hive certainly doesn't have that, but if I'm out and inadvertently left the CH running, a couple of taps turns it down. Ditto on return - if I'm a good half hour or more away, I may turn the CH back up before I set off, but usually don't bother.