Main Boiler circuit fuse blowing.

[ShaunCorbs]

Picture of backplate please

 

[Stevex]

This is the original backplate, new Drayton is exactly the same; see previous post, all sorted.

 

[ShaunCorbs]

Yes blue is neutral 1000%

 

[John.g]

Thinking the spare I had was faulty as it's been sat in my garage for about 15 years.
Just bought a Honeywell T6360. The original stat had 3 wires red, blue and yellow with the wiring labelled L, N and call.
I traced these wires to the junction box and the red is live, the blue goes to the CH pump and the yellow to the 3 port valve, so which terminals do the blue and yellow go to on the Honeywell?

Academic now but I installed one of these as a swap for a RTS1 for someone a while ago and connected Live to 1, Call (yellow) to 3 and N to 2 as far as I remember.