Changing old central heating programmer

[stratocaster]

Although c/h boiler replaced couple of years ago, the original Sangamo Western Timer was not (cant find any model number outside or inside) - its about 35 years (or more) old with pins that are inserted into the clock face to provide 2 on/off cycles a day and has 2 large switches that give (1) manual/off/auto and (2) heating and hot water/hot water. We have pumped c/h and gravity hot water with 1 room thermostat and no cylinder thermostat.

This timer has 8 wiring connections of which L, N, 5, 6, 1, 2 & 4 are used.

All modern timers seem to only have 6 connections.

Any ideas as to how I can connect one of these new timers?

 

[gas4you]

The only way I can think of is to forget the numbers on the wiring terminals and trace back/find what each wire is connected to and controls.

Once you know this it is then a simple matter of following the new programmers wiring guide.

Use of a multimeter will be required.

 

[gasman26]

You could even replace it with an up to date sangamo 7 day electronic control
http://www.sangamo.co.uk/web/site/Products/RPTS/e850_series_standard.asp

Great timeclocks, will probably out last the boiler....

You just need to determine whether you have a 3 or 4 pin currently, then its just a case of removing the old clock & plugging in the new (base plate is universal)

 

[nickso]

you dont say if the original timer is broken.

like gas4you says i would trace it back. most of the time the experienced will know immediately what wire is for what from memory or hunch. if you dont have a multimeter just apply 240 to each wire and see what starts up.....ch or hw.

your new timer will only need hot water only (boiler feed) and heating/water simultaneously (boiler feed, valve/pump feed) and mains feed of course.

im willing to bet the old timer will have links from the mains feed to common switches for ch/hw and switched lives from them to the boiler etc. the new timer wont need the links.

mark everything before you start so it can go back together!

 

[stratocaster]

Thanks guys - managed to get it all sorted with your advice - after the initial panic it was quite straight forward!