Honeywell 4200 3879 001

[mik36]

All

Hope you well and safe,

I have this old thermostat and with the glow worm 35ci combi boiler.

This thermostat seems to be not working.

It has three terminals

wires are connected

2--> BLUE

3 --> YELLOW

1--> RED

I checked for the voltage but there are no volts on any of these terminals

Can any one help

I checked the thermostat with multimeter and it does change reading with dial.

Pls help any ideas.


cheers

mik

 

[muggles]

You should have voltage between 1 & 2, if not then I suspect your programmer is broken. If there's no power coming in, you won't get anything out

 

[mik36]

programmer in boiler there is a power in to boiler

Do I need to have a look at the control board inside the boiler ?