Update old Newlic NLBRT 1 with Meross Smart thermastat

[funkyDIY]

Hi

Sorry if this is in the wrong topic but I need some help wiring in a new smart thermostat.

I have an old Newlic NLBRT1 thermostat (don't have a manual) which is on its way out. It connects to Honeywell ST699 programmable timer (for hot water and another one for central heating (I was going to leave the central heating timer on constantly). I have just bought a new Meross MTS200 (https://www.meross.com/en-gc/smart-ther ... mostat/132).

Could someone give me help me understand the wiring diagram?


This is what I have so far for the Honeywell.

Screenshot 2024-10-09 at 20.48.12.png (2.26 MiB) Viewed 388 times

From the Meross manual (https://d2utgrzbxqaq8t.cloudfront.net/p ... 477224.pdf)

Screenshot 2024-10-09 at 20.51.07.png (86.5 KiB) Viewed 388 times

[funkyDIY]

Am I correct in thinking it is a case of

Blue cable to slot 1
Red cable to slot 2
Yellow cable to slot 3

and if I want to fit the supplied external senor its a case of wiring the sensor up to slot 7 & 8?

[Someone-Else]

No.
If you do that, your boiler will never "fire"
The diagram shows a set of clean contacts, they are called that as they do not connect to anything else.
If you were to do as you suggest the new stat would work (as it has L & N) but when it switches nothing would happen as the yellow wire would be connected to .....................nothing. You need to also install a short wire from terminal 2 to terminal 5

[funkyDIY]

Amazing, thank you so much for your help, its working now and boiler is being called. Very happy now

[funkyDIY]

Not too shabby. I'm just disappointed the wallpaper was previously scratched.

[ericmark]

What are you going to do with the Honeywell ST699 programmable timer? I have been surprised at the cost to use an immersion heater, I assumed it would cost a lot more to use electric, but the new controller logs how much used each week, and cost less than the oil boiler, want oil boiler to be able to heat DHW as immersion does not heat enough for a bath.

I made a mistake, I fitted Nest Gen 3, looks good, but rather useless, as does not connect to TRV heads, so just fitted a Wiser thermostat as well, as Nest in hall, and sometimes living room would get cold, as hall cools too slow.

Seems there are TRV heads which link with your thermostat, so that's the next job.

[funkyDIY]

For the programmable timer, I've put some tape over the "Heating" button switches and put them on constant. The smart thermostat can control the timings and heating. I still need the "Hot water" setup from the timer for my immersing heater which is for hot water.

[ericmark]

I have something similar, my Nest Gen 3 works the DHW and can also work heating, but in the main the Wiser thermostat controls heating. I have four items in the living room, all giving me the temperature, three trying to control it.

So above the fire place 22.7ºC, other site of the door, Wiser says 23ºC set to 17ºC, so heating not running, one TRV set 22ºC and showing 21ºC the other set 20ºC showing 19.5ºC and I am trying to set them not to under or over heat. Nest in hall set to 16ºC and sitting at 20ºC as all now set to cool over night.

Getting central heating to work as wanted seemed so easy with first two houses, but mothers and this one have doors with no vents in them, and to get rooms at desired temperature has not been easy.