Sangamo mechanical timer Replacement?

[patchmeadow2]

Hi I have a Sangamo 255.2 mechanical 4 pin timer (round type) timing a Baxi Bemuda boiler gravity H/W system which after after 40yrs has developed a fault.
Could i replace it with a digital one? the Sangamo has 4 wires to it with the middle 2 being live + an earth wire. The C/H Pump works on the return and is switched on and off independently as required, simply stuff but works fine. The system as NO extras eg. diverters or room stats etc.
What make/type of Digital timer would do same job and be easy to wire up.
Thanking the experts in anticipation for any suggestions. DB

 

[Boilerman2]

You can still get Sangamo Timeswitches BUT the E850 Digital Round clock is about £150!!

A Honeywell ST9100 is a single channel Digital Timeswitch that would be easy to replace, you would have to fit a link in the base (see installation instructions!)

 

[tamz]

The wires to the old clock will be Live -3, N - 4. 1 and 2 is the switch which if the pump is worked independantly will power the boiler.

For a replacement you would need a single channel timer with volt free contacts like an ACL/Drayton LP111 or 711.

To wire it, put the wire from (old to new)

3 (on the old clock) to L (on the new)
4 to N
2 to 1
1 to 3

You would be better changing the wiring to the pump and working the heating from the clock too (you'd need a 2 channel programmer) but if you aren't sure just follow the above.

 

[patchmeadow2]

Thanx Boilerman2 and Tamz for responding to my enquiry & the advice on the wiring up from mechanical to digital. DB