Fitting a 3 wire room stat to a Potterton Heatmax

[bewsh]

Hey, alright? when changing a back boiler to a combi (potterton heatmax), the home owner wanted to keep the existing roomstat, which was a powered 3 wire stat. from the manufacturers instructions is says that it is possible to L and SL to the terminal block on the boiler and then the N goes to the fuse spur. what im wondering is instead of getting another wire coming from the stat to the spur (its not close to the boiler), could you simply put the N wire into the N of the main power terminal block on the boiler?

also, is it better to change the existing stat to a combi stat, 2 wires instead?

thanks.

 

[ChrisOxford]

from the manufacturers instructions is says that it is possible to L and SL to the terminal block on the boiler and then the N goes to the fuse spur. what im wondering is instead of getting another wire coming from the stat to the spur (its not close to the boiler), could you simply put the N wire into the N of the main power terminal block on the boiler?

Sounds reasonable, BUT could you post a link to the MI so that we can take a look at the wiring diagram?

also, is it better to change the existing stat to a combi stat, 2 wires instead?

Absolutely nothing wrong with a 3-wire stat, especially if the wiring's in place already, AFAIK.

 

[D_Hailsham]

the manufacturers instructions is says that it is possible to L and SL to the terminal block on the boiler and then the N goes to the fuse spur.

I can't see why they insist on the neutral being connected to the fused spur and not the neutral terminal on the boiler. As far as I am concerned a neutral is a neutral - unless it's a switched neutral.

Phone Potterton and ask them to explain.

Why not fit a Drayton Digistat+ or a Honeywell DT90E? No neutral required with either and they are more acurate than the mechanical stats.

 

[ChrisOxford]

As far as I am concerned a neutral is a neutral - unless it's a switched neutral.

Totally agree. It certainly won't be fused (except in some ancient installations, or in medical equipment).