Room Stat Problems

[Al Growler]

Decided to change room stat as current one old and starting to have 2/3 degs between turning boiler on and off.

Just wanted a basic dial model, and purchased a Drayton, but whilst it clicked on it wasn't clicking off. Replaced it with a Honeywell T6360. Works OK, but the click on/off is around 16 degs on the dial, although room temp is actually 21.5 at that point, so I am having to use 16 degs as the required temp. My fitter initially said that it was because the stat was cold and needed time to warm up, but it's been in a couple of days.

Any help and advice as to how can I can get accurate dial reading Would be appreciated. Thanks.

 

[cross thread]

has it got a neutral connection.

 

[Al Growler]

Just had a look at fitting instructions, and it says ' a neutral connection must be made when the heating load is less than 6 amps'. Assume it must be as neutral wire is connected to terminal 2 in the box. I have blue wire in terminal 2, yellow in 3 and red in 5.

Thanks for your reply.

 

[Hot&Cold]

Is the neutral wire connected in the wiring centre/boiler. During a call for heat if you have 240v on honeywell terminals 1&2 you have.

The room thermostat can be temperature tested with a calibrated digital thermometer attached to the wall next to the room thermostat but not blocking any air flow route.Leave on test for a few days and note the temperatures differences.

Thermostats can have operating tolerances,check your manufacture information instructions.
Thermometers will also have operating tolerances.

Thermostats are influenced by local heat/cool factors and user expectation is also a consideration.These can only be checked onsite

Your honeywell thermostat can be re calibrated if necessary or re calibrated to suit your own needs but you need a calibrated digital thermometer-nothing less.

 

[Al Growler]

Is the neutral wire connected in the wiring centre/boiler. During a call for heat if you have 240v on honeywell terminals 1&2 you have.

The room thermostat can be temperature tested with a calibrated digital thermometer attached to the wall next to the room thermostat but not blocking any air flow route.Leave on test for a few days and note the temperatures differences.

Thermostats can have operating tolerances,check your manufacture information instructions.
Thermometers will also have operating tolerances.

Thermostats are influenced by local heat/cool factors and user expectation is also a consideration.These can only be checked onsite

Your honeywell thermostat can be re calibrated if necessary or re calibrated to suit your own needs but you need a calibrated digital thermometer-nothing less.

Thanks for your reply Old&Cold. I have had one digital and one normal thermometer propped up on top of the stat for a couple of days. This is what I have found.

At the moment, both thermometers are reading 20.1. Switch off temp on stat is 16.5 and switch on 16.0, so that in itself is working spot on imo, it's just I have 4 deg difference between stat and actual.

Also just checked inside stat and the ports are numbered differently to diagram on the installation instructions.

Red in the one numbered 1, yellow in 3 and blue in 2.

Also note that is a tab of plastic attached to the dial on the 20 deg mark.

 

[Al Growler]

Got this sorted. Didn't expect a new stat to need calibrating and to be out by 5 degs. Tried to get the dial off before, but appeared that it didn't come off. Got it off anyway, and ensured click off was room temp as per independent thermometer, and put the dial back. Job done