Potterton boiler starting unexpectantly

[m550344]

I have recently replaced my hot water cylinder tank, which came with a new cylinder stat (Danfoss Control\Limiter model). What I am having a problem with now is that I cannot get the cylinder stat to trigger the boiler when temperture of water falls below a given temperture as set by cylinder variable stat. The programmer is a Potterton EP2001.

I have live on C, and 1 and 2 wired as per orginal stat (Honeywell Cylinder Thermostat L641A1039). If I set stat to any temperture above 30c boiler will not trigger, however if I set to 30c boiler triggers and will remain on until I switch programmer off. I also found that boiler would trigger unexpectantly when programmer was set to off.

Is it likely that the Danfoss stat is not compatiable with the programmer or maybe my programmer is at fault?

 

[Jimbob]

Needs to tested to see if it wired correctly, by somebody competent aswell as heating controls can be a nightmare. Does it have 2x2 port valves or a 3 port valve, Also is it mid position or a diverter if it is a 3 port valve?

 

[m550344]

Thanks Jimbob. Had worked on basis that wiring from the old stat to new would be on a like for like basis, as connections appear to be the same (C,1,2). System uses mid-position 3 port valve. I could use the old stat to narrow down the problem but a loathe to cut into the foam insulation on the new cylinder. Looks like this will probaly be the best solution to validate assumptions