Drayton RTS8 - testing

[marev]

Hi.

Thermostat is working fine. However, just wanted check this is how a test should show.

When I put a tester across L & 2 with the thermostat turned off, the tester lights up and when I click the thermostat on the lights go out.

Is that the correct sequence? Just a bit confused as I would have thought it would be the other way round. i.e when the circuit is closed (thermostat on) the tester lights will be on, and vica versa.

Hope that makes sense.

 

[stem]

What kind of tester are you using? One that measures voltage, or one that measures resistance?

 

[marev]

Voltage

 

[stem]

If you are measuring voltage, then it will only illuminate when there is a potential difference (voltage difference) between the two points. When the thermostat is 'on' both terminals will be connected together by the switch inside the thermostat and so both terminals will be at exactly the same voltage. So, no voltage difference = no indication.

By putting the tester between L and 2, you are connecting the tester in series with the boiler components and when the thermostat is 'off' and the switch open and the terminals no longer connected together, you are detecting some voltage difference between the two points probably because of the boilers internal components.

The proper way to test voltage (assuming your tester is rated at 230V) is to put one probe on neutral (ie a known 0V) and then the other becomes the test probe. In this instance with one probe on N and the thermostat set to be 'on' you will find by putting the other probe on terminals L and then terminal 2, it will indicate in both instances.

 

[marev]

Many thanks for explaining this.

All makes sense now