Replacing a room thermostat - mechanical to digital

[Charnwood]

Not too far from Newark is the in-bred centre of England, so I'm told.

The actual centre of England is somewhere between Leicester and Coventry IIRC.

 

[Terry7556]

in-breeding isn,t exclusive to newark

 

[Charnwood]

Not Newark exactly, a few miles west.

 

[Charnwood]

You should connect the brown to A and the green/yellow to B. Put the blue in a connector block somewhere safe.

......assuming everything at the thermostat end is plastic, it will comply.

Done all that and..........

IT LIVES!!! Half an hour in and all seems hunky dory. A couple of test 'boosts' up and down and the boiler seems to be obeying orders.

WTF can I get brown sleeving? Wickes seem to do just G/Y, B&Q G/Y or blue.
Might have to accost a sparky for some.

 

[mikep723]

D_Hailsham - Many thanks for the wiring instructions to replace three wire dial thermostat with digital two wire, red=A; yellow=B; blue=isolate in connector , boiler now fires up without long delay and house stays warm. Excellent advice!

 

[MarkT1967]

Hi guys, I'm looking to do the same thing as the op, is it still the case of using the Honeywell? I'm looking to set a maximum on the upper temperature as my kids like to roast at 25degrees lol, I had the old RTS1 set to around 21degrees, this worked well until the clip broke so I thought instead of changing the stat to the same, I found this site and thought hey why not go digital.
Thanks
Mark

 

[thechief1979]

Hi all, just bumping the question from MarkT1967m - is the DT90E still the preferred replacement for the RTS1?

I have a Heatrae Sadia Megaflo with a drayton programmable controller - is the DT90E suitable?

many thanks

 

[stem]

You can replace a RTS1 with a DT90, whether it is preferred or not is entirely up to you. You may wish to replace a Ford with a VW, others would prefer to replace their Ford with a Vauxhall. All thermostats have the same function they are simply switches they turn the central heating 'on' or 'off' and that's it. [Nothing to do with the Megaflo that's for the hot water]

The difference with the DT90 to the RTS1 is that the DT90 has a display and so is battery operated to maintain the display when the programmer switches off the power to the thermostat.

The RTS1 connections are:

As the DT90 is battery operated, it doesn't need a neutral, so the wire in the N terminal shown above should be isolated / insulated and tucked safely out of the way. The remaining two wires in 'L' and 'Call for Heat' would be connected to the DT90E as follows:

RTS1 L = DT90 'A'
RTS1 Call for Heat = DT90 'B'

 

[Keithmac]

What's the main benifit from going from mechanical to digital thermostat if you already have a digital programmer?.

 

[stem]

Digital thermostats are more accurate than the old mechanical devices, and so maintain a more stable temperature. They also display the actual and set temperatures digitally, which may or not be an advantage to you personally.

A programmer is a different device and serves a different purpose. It is just a time switch that turns the heating on and off, as well as the hot water, if you happen to have a system with a hot water cylinder. It has no control of the room temperature.