How to replace a Room Thermostat

[Steven Ferguson]

Sorry to jump on this thread but I need help replacing a room stat.
The boiler is an old oil fired worcester danesmoor 20/25 with a honeywell roomstat, I'd like to change it for a salus rt510 or something similar, the current roomstat has an earth, a live, a negative and a black wire (not sure if this is a switched live) I wired it all up yesterday and it powered up but had no control of the boiler, if the black wire is a switched live how do I return the signal back to the boiler. Any help would be great.
Regards
Steven

 

[stem]

Then you should really start your own new thread. Tagging your question on to someone else's is known as Hi-jacking and is against the forum rules. This causes confusion particularly as this thread is still live as there will we some answering your question and others that of the original poster.

I have asked the moderators to move it for you.

 

[stem]

Now you have a separate thread going, I will see if I can assist. If your Salus receiver looks like below, and the original thermostat was switching 230V to the boiler....

...then:

The Live and Neutral go to L and N respectively
The boiler switched live goes to NO
Then you add a link between the L and COM terminals so that they are joined together

If anything is different or you are unsure, post back. The model number of the original Honeywell thermostat and where each of the wires went would allow positive confirmation.

 

[Steven Ferguson]

Great thank you for that, I'll give it a shot.
Regards
Steven

 

[Steven Ferguson]

Hi Stem
Do I just disregard the earth or attach to a fixing.

Regards

Steven

 

[stem]

Thanks for the photo. I can confirm that:

Brown wire in 1 is live
Blue wire in 2 is neutral
Black wire in 3 is switched live

So you are OK to proceed as per my earlier post.

I usually put the earth in a separate screw terminal and tuck it safely out of the way so that it doesn't inadvertently contact anything.

The new thermostat is a programmable thermostat, which means that it incorporates both time and temperature control. Your old thermostat doesn't have time control, so will probably be connected to a programmer / time-switch elsewhere. If it is, the heating control at the existing programmer will need to be set to be permanently 'on' 24/7. that way it will allow the Salus to control the time & temperature of the system and not interfere with it.

 

[Steven Ferguson]

Thanks Stem it worked a treat.
Regards
Steven

 

[Steven Ferguson]

Hi Stem another question if I wanted to upgrade to hive in the future would that be possible, I understand I'd probably need a dual channel controller as I have a hot water tank upstairs.

 

[ianmcd]

you could use the single channel hive to control just your heating and use whatever you currently use for the HW, or you could use the dual Hive to possibly control both what do you currently use to control the HW ?

 

[Steven Ferguson]

ianmcd thanks for the reply the boiler has a built in programmer for the HW and CH.

 

[Steven Ferguson]

Thanks for the photo. I can confirm that:

Brown wire in 1 is live
Blue wire in 2 is neutral
Black wire in 3 is switched live

So you are OK to proceed as per my earlier post.

I usually put the earth in a separate screw terminal and tuck it safely out of the way so that it doesn't inadvertently contact anything.

The new thermostat is a programmable thermostat, which means that it incorporates both time and temperature control. Your old thermostat doesn't have time control, so will probably be connected to a programmer / time-switch elsewhere. If it is, the heating control at the existing programmer will need to be set to be permanently 'on' 24/7. that way it will allow the Salus to control the time & temperature of the system and not interfere with it.

Hi Stem I did as you said and set the programmer to on 24/7 Central heating, Is there a way to stop the hot water firing up the boiler outside of the programmed times for the central heating.

 

[stem]

Usually the programmer has two channels. One for heating and one for hot water. Only the Central heating channel should be set to be permanently 'on' but and the hot water channel can be left as it was to control the hot water on & off times.

 

[ianmcd]

I have a feeling that you might have Gravity HW can you post some pics of your HW cylinder

 

[ericmark]

My boiler nearly the same as yours the original programmer had an option for DHW without CH but not CH without DHW. I was advised when I swapped the programmer that since the old oil boiler has no cool down time, it was better not to put any motorised valve on the DHW, I may have been advised wrong? However the new system is the same, can't have CH without DHW, and in winter I turn off the DHW timed heat as it does not need it.

Now I have Nest, so not limited to 1 or 2 slots a day, in summer DHW heated every other day, and in winter the thermostat changes temperature settings 6 times a day. I assume you can do same with Hive, since needs an hour gap between each setting I suppose limit is 24 settings a day, but never tried.

However the advantage of Nest and I assume same applies to Hive is the occupancy detection and geofencing which automatic turns down heating when you leave the house. Assuming you don't forget your phone. In the morning to stop the heat over shooting, I move from 17°C overnight to 19°C then increase it by 0.5°C per hour until at 20.5°C this is because the design of the hall with the wall thermostat in means the heat from hall radiator takes a long time to reach wall thermostat, once at new temperature it works A1, and the programmable TRV heads keep all other rooms at set temperature.

However when I leave house and return, the heat goes straight to 20.5°C so tends to over shoot, it is not the over shoot that is the problem, but it means boiler remains off for a long time as hall cools, which in turn means other rooms can cool too much.

I like Nest and it is possible Hive is better as Hive TRV heads can link to the wall thermostat. However I am undecided about the geofencing and occupancy detect. With the over shooting problem maybe better if the geofencing and occupancy detect is turned off? At least on Nest, maybe just use the geofencing on the TRV heads so dinning room and living room cool but hall stays warm?

So the big question, why do you want Hive, what do you expect it to do for you?

 

[Steven Ferguson]

View attachment 180806 My boiler nearly the same as yours the original programmer had an option for DHW without CH but not CH without DHW. I was advised when I swapped the programmer that since the old oil boiler has no cool down time, it was better not to put any motorised valve on the DHW, I may have been advised wrong? However the new system is the same, can't have CH without DHW, and in winter I turn off the DHW timed heat as it does not need it.

Now I have Nest, so not limited to 1 or 2 slots a day, in summer DHW heated every other day, and in winter the thermostat changes temperature settings 6 times a day. I assume you can do same with Hive, since needs an hour gap between each setting I suppose limit is 24 settings a day, but never tried.

However the advantage of Nest and I assume same applies to Hive is the occupancy detection and geofencing which automatic turns down heating when you leave the house. Assuming you don't forget your phone. In the morning to stop the heat over shooting, I move from 17°C overnight to 19°C then increase it by 0.5°C per hour until at 20.5°C this is because the design of the hall with the wall thermostat in means the heat from hall radiator takes a long time to reach wall thermostat, once at new temperature it works A1, and the programmable TRV heads keep all other rooms at set temperature.

However when I leave house and return, the heat goes straight to 20.5°C so tends to over shoot, it is not the over shoot that is the problem, but it means boiler remains off for a long time as hall cools, which in turn means other rooms can cool too much.

I like Nest and it is possible Hive is better as Hive TRV heads can link to the wall thermostat. However I am undecided about the geofencing and occupancy detect. With the over shooting problem maybe better if the geofencing and occupancy detect is turned off? At least on Nest, maybe just use the geofencing on the TRV heads so dinning room and living room cool but hall stays warm?

So the big question, why do you want Hive, what do you expect it to do for you?

Thanks for your reply what I'd like is more controllability over the boiler, I understand that when ch is on the dhw will heat also but I'd like to stop the boiler firing to heat the hot water when the heating is off.
Regards
Steven

View attachment 180806 My boiler nearly the same as yours the original programmer had an option for DHW without CH but not CH without DHW. I was advised when I swapped the programmer that since the old oil boiler has no cool down time, it was better not to put any motorised valve on the DHW, I may have been advised wrong? However the new system is the same, can't have CH without DHW, and in winter I turn off the DHW timed heat as it does not need it.

Now I have Nest, so not limited to 1 or 2 slots a day, in summer DHW heated every other day, and in winter the thermostat changes temperature settings 6 times a day. I assume you can do same with Hive, since needs an hour gap between each setting I suppose limit is 24 settings a day, but never tried.

However the advantage of Nest and I assume same applies to Hive is the occupancy detection and geofencing which automatic turns down heating when you leave the house. Assuming you don't forget your phone. In the morning to stop the heat over shooting, I move from 17°C overnight to 19°C then increase it by 0.5°C per hour until at 20.5°C this is because the design of the hall with the wall thermostat in means the heat from hall radiator takes a long time to reach wall thermostat, once at new temperature it works A1, and the programmable TRV heads keep all other rooms at set temperature.

However when I leave house and return, the heat goes straight to 20.5°C so tends to over shoot, it is not the over shoot that is the problem, but it means boiler remains off for a long time as hall cools, which in turn means other rooms can cool too much.

I like Nest and it is possible Hive is better as Hive TRV heads can link to the wall thermostat. However I am undecided about the geofencing and occupancy detect. With the over shooting problem maybe better if the geofencing and occupancy detect is turned off? At least on Nest, maybe just use the geofencing on the TRV heads so dinning room and living room cool but hall stays warm?

So the big question, why do you want Hive, what do you expect it to do for you?

TV

Hi and thanks for your reply, I'd like to have more control over the boiler, I understand that when the ch is on it will also heat the dhw but when ch is off it still fires up the boiler maintaining HW temp which I don't want.