Changing a Thermostat stuck with wiring

[smon jones]

Hi I have a old Honey well Thermostat I would like to replace with a digital Thermostat but stuck with wiring. Please advise
This is old Thermostat
View media item 102938View media item 102937This is new Thermostat
View media item 102935View media item 102936I wired them up the same as numbers but blew the 3AMp fuse in the boiler not good
Old one is back on at moment

 

[ianmcd]

you havent posted the pics

 

[smon jones]

Uploaded pictures now i hope

 

[smon jones]

This is the new tbermostat

 

[ianmcd]

Yellow from old stat to 1 in new stat
Red from old stat to 2 in new stat
Blue in old stat must be safely terminated as is not used in the new thermostat, I think you used the blue and thats what has blown the boiler fuse

 

[SFK]

..

 

[smon jones]

On the old there is 3 wires and Earth. Red yellow and blue. Which colour goes to which number please

 

[ianmcd]

you are only using the red and yellow wires the earth and the neutral must be safely terminated, I have already posted what coulour goes to which number

 

[smon jones]

Thanks let me try that later.

 

[undertrained]

Yellow from old stat to 1 in new stat
Red from old stat to 2 in new stat
Blue in old stat must be safely terminated as is not used in the new thermostat, I think you used the blue and thats what has blown the boiler fuse

Me learning: Can I just ask, why would the wires change? I thought 1 on Honeywell (live) would go to live (1) on new stat and 3 from Honeywell (switched live) to 2 (switched) in new stat?

 

[bernardgreen]

why would the wires change?

There is a small advantage in putting the Load to the Common of a changeover switch and the Live to one of the contacts.

If the Live is connected to Common then when heating is not required the unused terminal becomes Live.

 

[andytw]

..

 

[ianmcd]

Me learning: Can I just ask, why would the wires change? I thought 1 on Honeywell (live) would go to live (1) on new stat and 3 from Honeywell (switched live) to 2 (switched) in new stat?

3 on the new stat is switched live for air conditioning, if you look closer you will see 2 has heat written on it and 3 has cool written on it, the new stat is a foreign make if it had been a new Honeywell then the numbers would probably have been the same, the numbers and colour of wires in heating controls seldom means anything, it is up to who wired it up

 

[undertrained]

3 on the new stat is switched live for air conditioning, if you look closer you will see 2 has heat written on it and 3 has cool written on it

- yes I did see that and wondered what the cool bit was for. I was just to engrossed in the live being on a different number.

 

[ianmcd]

- yes I did see that and wondered what the cool bit was for. I was just to engrossed in the live being on a different number.

The red wire doesnt mean that it is live