Honeywell Thermostat T6360B1028

[john2k]

I have a honeywell t6360b1028 thermostat wired as the picture below. Just wondering, is there a reason why this thermostat relay will activate even though the room temperature is higher than what the thermostat is set to? for example if I set it to 15 so I know it's definately off and a room thermometer shows room temp next to the thermostat is actually 21 degrees but at 15 degrees the thermostat kicks in.

pic below:

 

[ianmcd]

but at 15 degrees the thermostat kicks in.

Do you actually mean that the radiators stay on, or are you measuring with a multi-meter and the stat is calling ?

 

[john2k]

Do you actually mean that the radiators stay on, or are you measuring with a multi-meter and the stat is calling ?

So basically let me try and explain it a bit better. If I set the temperature on this thermostat to 20° and the room temperature is below 20° then the thermostat is supposed to make that clicking sound at the 20° mark which basically then activates the relay which then turns on the boiler to heat the heaters. So this concept works except the temperature at which the thermostat clicks and activates seems to vary by a few degrees sometimes 4° or so compared to thermometers that I have just got in the room. So my thermometer shows room temp as 22 but this thermostat is activating at the 18° mark and turning the boiler on.

 

[ianmcd]

just fit a new one then, nothing else you can do

 

[ericmark]

I have a TRV and a wall thermostat in hall, in summer show same temperature but winter the wall thermostat can show 4°C higher than the TRV.

I've seen this many times, late mothers house seen 8°C diffrence in same room when sun shines through the window.

So it depends where your measuring the temperature. Thermometer needs to be at the thermostat. Old house cold wall resulted in needing to set thermostat lower than required heat.

In most rooms best place for thermostat is below the radiator so it measures the return air, so standard location of a TRV is about right.

So wall thermostat just stops boiler cycling on warm days, and being within a few degrees is good enough.

 

[stem]

Unlike the new electronic thermostats these old mechanical designs have small moving parts that wear; as they get older they get inaccurate.

 

[john2k]

Yes it does seem to be exactly 4 degrees offset from what a normal thermometer reads. Is there no way to adjust the dial the adjust the offset? If not I guess I will probably change it out with a digital one.

 

[stem]

No time to replace it, these old types contain bi-metal strips / discs and they can get fatigued and distorted. Nothing to be done to fix it. A digital thermostat is the way to go; solid state components and the switching done by a relay.