Room Thermostat

[old wrinkly]

I have just had a new hwc installed as part of a general upgrade to try and conserve my use of central heating oil.

Previous posts on the form has suggested fitting a room statto control the boiler rather than relying on TRVs.

I have a Honeywell wiring centre box and a Horstmann Centaur Plus C27 programmer.

I also have a Towerstat RS Room thermostat that I have had for sometime and was going to use that but the plumber who fitted the hwc didn't seem impressed when I said what I was going to used and said I would be better of with a Honeywell or Horstmann.

Would welcome any advice on an alternative room thermostat as I thought all room thermostats were the same and didn't really want to buy another one unless there was a very good reason.

Thanks

 

[bengasman]

What is a hwc?
Horstman is crap.
Programmable roomstat is most convenient, stick to Siemens or Honeywell

 

[old wrinkly]

Hi, sorry for the confusion hwc=hot water cylinder.

Not going to change the Horstmann programmer until I have to.

Just want a simple mechanical room thermostat don't need a programmable version.

 

[bengasman]

Don't know the towerstat inside, I either use the Honeywell or a replica of that.

 

[old wrinkly]

Quick update please.

A friend has offered me a Honeywell DT200 digital room thermostat or a Honeywell T6360 room thermostat.

Both of these mention two wire switching.

I seem to remember my plumber saying something about the towerstat being three wire switching which was "good" although he didn't like the item itself.

Will either of the above Honeywell room thermostats work in conjunction with my Horstmann Programmer and what is the difference between two wire and three wire switching

Thanks

 

[D_Hailsham]

A friend has offered me a Honeywell DT200 digital room thermostat or a Honeywell T6360 room thermostat.

The DT 200 is the more up-to-date and more accurate than the T6360, which uses outdated mechanical technology.

It can be used with any boiler.

 

[old wrinkly]

Thanks for the reply, looks like it will be the DT 200 then.

 

[old wrinkly]

I have now got the DT200 but vague as to the correct method of connecting to the Horstmann Centaur Plus C27 programmer.

I have checked the connections on the programmer by taking of the front plate and these are as follows, reading left to right:

N (with clock icon)

L

1 (HW OFF)

2 (CH OFF)

3 (HW ON)

4 (CH ON)

The DT200 has 3 terminals A B C.

I am running a Boulter Bros Camray External Oil Boiler.

Would appreciate help on the correct wiring sequence.

Thanks

 

[D_Hailsham]

You will have to break into the wire connected to terminal 4 (CH ON), somewhere along the line. Connect Terminal A to the Timer side and Terminal B to the other side. Terminal C is not used.

Obviously, depending on where you site the thermostat, you may have to extend the wire.

Original

[Terminal 4] ------------------------------[Usually goes to a Motorized Valve]

New

[Terminal 4] -----------[A B]------------[Usually goes to a Motorized Valve]

 

[old wrinkly]

Thanks for the info.

I have checked the wiring on the programmer again and pin 4 (CH ON) is black with a yellow sleeve so I am assuming it's a switched live.

Should I be able to pick this up in the wiring box, would make life easier as it's nearer the thermostat.

Just to be sure I understand terminal A of the thermostat gets connected to the output going to the programmer and terminal B is the input from the thermostat?

 

[D_Hailsham]

I have checked the wiring on the programmer again and pin 4 (CH ON) is black with a yellow sleeve so I am assuming it's a switched live.

Should I be able to pick this up in the wiring box, would make life easier as it's nearer the thermostat.

You should be able to!

If you have a mid position valve (left pic) the wire from the programmer goes to the same terminal as the white wire from the valve.

If you have two zone valves (right pic) it will go to the brown wire from the valve connected to the rads. The other valve goes to the HW cylinder and should be obvious.

View media item 5946View media item 11762

Just to be sure I understand terminal A of the thermostat gets connected to the output going to the programmer and terminal B is the input from the thermostat?

I would put it the other way round! The programmer CH ON supplies 240Vac to Terminal A and Terminal B supplies 240V to the valve when the thermostat switch closes.

 

[old wrinkly]

Task completed......thanks for all the help