Room Thermostat

[soulman]

Hi, I came across a room thermostat today without a cover, i tested for voltage at the terminals & it was live.  I went to get a replacement & purchased a honeywell t6360.  The room stat had a perm live & a switch live but no neutral connection.  The wiring diagrams states that a neutral connection must be made if the heating load is less than 6A.  For applications above 6A no neutral is required, I then measured current on switch wire which was 0.35A. 

My first question is why would a thermostat need a neutral below 6A but not above?

Can anyone recommend a suitable replacement that doesn't need a neutral?

Cheers

 

[ProDave]

the neutral connection is normally only needed for a mechanical thermostat, to power an internal  "accellerator" heater when the thermostat is switched "off".  That reduces the hysteresis between the switch on and switch off temperatures that you otherwise get wih mechanical thermostats.

If it's an electronic stat, it won't have any hysteresis and has no need for a neutral connection. 

 

[Steve3948]

Shunt on older stats

 

[soulman]

Cheers Dave, Steve, I'll purchase an electronic stat.

 

[Andy™]

it will work without the neutral, just not as effective

 

[batty]

Siemens stats don't need a neutral SF sell them wicks used to sell them not sure if they still do though. RAA20

http://www.discountedheating.co.uk/shop/acatalog/Siemens_Double_insulated_Room_Thermostat_Raa20_4569871.html

 

[SLIPSHOD & SLAPDASH]

Dont do like most plumbers and connect the earth to that terminal, or worst still use the CPC as a neutral.