DRAYTON SM2 PROGRAMMER

[jws]

i have replaced my programmer for water and heating which operated my old vulcan continental boiler. I replaced it with a drayton SM2 programmer and although the programmer shows all is working the CH pump does not come on.
The old progammer Sangamo 410 was wired up as
1 CH ON
2 BLANK
3 LIVE WITH LINK WIRE FROM 8
4 CH OFF
5 WATER OFF
6 LIVE N AND E ISOLATED
7 BLANK
8 WATER ON AND LINK TO 3

The SM2 is

N
L
1 HW OFF
2 CH OFF
3 HW ON
4 HW ON

Any suggestions as to what I need to do to get the pump to kick in would stop me banging my head against the wall and make me feel warmer.
JWS

 

[JohnD]

you have connected the room stat according to the makers instructions?

some programmers have a setting on the back for gravity HW/fully pumped.

you do not mention the connections for the cyl stat, room stat, pump, 3-port valve etc. It is easier to gather all these together in a Connection Centre (=junction box) according to the wiring diagram supplied with the programmer.

I can't help though without referring to the makers instructions (which I'm sure you have done)

p.s. I did install one of these last year for my old mum, and had to get an extra wiring diagram from Drayton (Invensys) as she has an old gravity/pumped installation which is not covered in the usual instructions.

IIRC their instructions show how to convert when replacing various existing common programmers

 

[jws]

thanks for that
The programmer is connected to the pump via the roomstat although I.m not aware of the stat ever working. I will recheck the wiring to the stat and the junction box at the boiler. On the SM2 There is a link facility which I have left in place as per instructions for gravity water/ pumped CH. I will let you know how I get on
JWS

 

[nicknox]

On your description you have 2 HW off?

 

[jws]

Sorry about that 4 should read CH ON