Replacement for Sangamo clock

[kerm]

The Sangamo clock/boiler switch on my central heating boiler has failed - intermittently at first, but now seems to have stopped permanently. I replaced this clock about 10 years ago and had trouble then finding a the same model, but eventually tracked one down - it wasn't cheap!. It is round bodied (3.5 inches diameter) with a transparent dome at the front fitting onto a round bakelite case.

There are 4 wires leading to the connectors at the bottom of the clock, marked on the controller as 'clock motor' (red & black) and 'clock switch' (both purple).

If, as I suspect, I cannot find the same clock again would it be straightforward using a different clock? The Sangamo clock has a manual on/off switch for the boiler (which I need) and a 'day' dial, presumably to have the boiler on or off at set week days only (which I don't need).

The boiler, a Glo-Worm Sunrod G50 (37 years old and still going strong!) has a custom metal bracket with three holes to match the clock body, so I suppose I'd have to adapt this, but if I tried another clock would there be other problems/pitfalls?

I'd appreciate any advice.

Thanks,

John

[TimM]

Do you mean one like this? (Not me selling it)

[Dave Plowman]

You can still buy Sangamo, but expect to pay near 100 quid.

But all you really need is a simple time switch. Have a look at 'Timers' on the TLC site - I'd say the the TC GP24 at 15.45 or the electronic (with battery back up for mains failure) TC CP124 at 24.95 (both plus VAT) would be fine.

[kerm]

Thanks - but will it be simple to wire in? I've been told that if I use a different clock it would need rewiring.

Thanks,

John

[kerm]

?? - no link posted??

John

[Christian McArdle]

It sounds like you have very simple wiring as it is.

I bet you have one permanent power cable (the red/black motor one) and one switch cable (purple switch one).

Almost time clock with "volt-free" contacts should be simple to wire up. Connect the purple wires to COM and NO. Connect the red wire to L(ive) and the black wire to N(eutral). (Unless the old one is a low voltage thing, but I doubt it in on a 37 year old boiler).

Christian.

[Pat E]

It is ok to use a different type timer. You will have no problem getting one from a good heating / plumbing supply shop. I recommend you get a "mechanical" type timer as opposed to a "digital / electronic" type as you have to remember the setting steps when you want to adjust them. Also you will need to decide if you want a 24 hour or 7 day timer. Hope this helps --- Pat E

[Dave Plowman]

The only reason I can think of is that the boiler connection is low voltage. I'm not sure whether either of the switches I mentioned have separate switch contacts or have a link which can be removed to provide this.

[kerm]

Thanks everyone for the advice.

I got the Trac TC GP24 (voltage free contacts) but it does't work.

The wiring connection instructions state:

"1. Live output to appliance

1. Make link to switch 240v AC ONLY

NB terminal 2

Should you wish to switch other than 240v AC do not use link to terminals 2 and 3. Feed the required switching voltage to terminal 2 and output from terminal 1

1. Live from mains (link shown to 2 - I linked these)

1. Neutral from mains and neutral output to appliance"

Assuming I was switching 240v AC I connected the two purple 'clock switch' wires to terminals 1 and 4, the red 'clock motor' wire to terminal 3 and the black 'clock motor' wire to terminal 4 and inserted a link between 2 and 3.

When I reconnect to the mains with the timer turned to 'permanently on' I can hear a click from the timer but the boiler does not come on. I replaced the old Sangamo switch to check this still worked on manual and it does (so no other damage done!).

Any ideas what I've done wrong?

John

[Christian McArdle]

You are lucky you didn't blow the thing up.

As I said, the red/black wire is L/N and the purple wires are for the contacts. Don't go connecting the purple wires to mains willy nilly. To do so makes assumptions about how the switching works. They could have been low voltage.

Use:

1. Purple
2. Purple
3. Red
4. Black

And whatever you do, remove the link between 2 and 3.

Christian.

[kerm]

Now rewired and working fine - many thanks!

John