central heating programmer replacement

[1WeeShell]

Hi
Can anyone help me with a central heating problem?
The Baxi back boiler kept cutting out and needed to be reset. A friend (installation engineer) told me he thought that the programmer was faulty as current was not getting through. As I had a spare he suggested I swap it in and see if it worked. I went to do so and found it more complex than expected as they were quite different. My engineer is off with an injury but told me I should be able to find a model to do a straight swap but I can find no results when I search Honeywell 4200374-001 and it is New Years Eve. I tried calling Scottish Gas but they cannot get some one out till week from now. Meantime my Tenants are having a very cold holiday. How would I wire the one I have till the merchants are open again and can any one tell me what a compatable replacement would be?
see image

 

[ianmcd]

you say the back boiler kept cutting out and needed to be reset ? what exactly are you re-setting and how ?

 

[1WeeShell]

On the front of the fire, behind the plate there is a light, when it is red or flashing red it needs to be reset. to do this one turns the thermostat knob to the off position and wait until the light shows orange. Then turn the knob to required setting and the boiler commences the ignition sequence

 

[ianmcd]

very unlikely to be anything to do with your programmer, it is more likely to be a faulty PCB on your back boiler