Wiring to Honeywell thermostat.

[spongsdad]

I have recently moved into a bungalow in which the radiator response seems "sluggish" By this, I mean that when the heating fires up, everything gets nice and warm but when the pump stops, the thermostat is slow to respond to the temperature fall. The stat is a Honeywell T6360B with the live feed to terminal 1 and call to terminal 3. The wiring diagram shows a neutral connection to terminal 2 but this has not been used. However there are two black conductors available, presumably the neutral to the live feed and the call. These are joined by a connector and are in the box behind the stat. Before I use these to make terminal 2 connection, am I missing anything? The system is pumped hot water and central heating using a Honeywell 4073 3 way valve and of course a cylinder stat. Any help or suggestions gratefully received just in case I am missing something obvious.

 

[MANDATE]

Well I think you are missing something.
A wire going to a 'load' is either a 'live' or a 'switched live'. It is only a 'neutral' after the 'load'
A basic on/off switch is not a 'load' so its 'live' in and 'switched live' out.
Now some room stats are just a two wire job, cause it's a switch.
However some room stats incorparate a miniture type of heater and this heater of course is a 'load' and therefore cannot function without a neutral wire to complete the circuit. So you have both a 'switch' and a 'load' but the stat will function without the load and that is how yours appears to be working. If you now want the 'load' to function, you have to provide a 'neutral' wire. This would need to go from neutral side of the load back to the terminal box where it would join to other neutral wires.
term 1.........live from term box.
term 2......load.......neutral to.........term box
term 3..........switched live...........3 port valve
Hope this helps

 

[spongsdad]

Thanks Mandate. Obviously my terminology is wrong. I used the term "call"for terminal 3 rather than "switched live" Terminal two is obviously for what I know as the accelerator heater and if I understand you correctly, that will take the neutral back to the terminal block and allow the heater to function.
Thanks for the help.

 

[MANDATE]

Yes you've got it! If your thinking of using one of the black conductors I would check out first what purpose if any they are serving. One of them could already be connected to neutral.
If that does not cure your problem I would check out the 3 port valve. I had a situation and suspected the room stat was faulty. CH was intermittent, then I discovered it was OK providing HW was also being demanded and not satisfied. When CH only was called for,which is the state as soon as HW is satisfied there was nothing.
Eventually found 3 port valve moved to correct position but no power out put from the valve orange wire. Every indication that valve had faulty microswitch which was confirmed later ( after fitting new valve head)

 

[Softus]

So you have both a 'switch' and a 'load' but the stat will function without the load and that is how yours appears to be working.

On a subtle and pedantic point, a two-wire stat will operate as a switch without the compensator neutral connected, but as a stat it won't function as designed because it won't measure accurately.