Honeywell ST699 Timer

[ORGANIC]

I’m looking for a bit of advice on the Honeywell ST699 timer.
I think I have the right model number. The problem is that the clock will change time by it’s self. e.g. AM to PM or might jump one or two hours. Will the battery need changing in it. Is there a reset for it? If so were.
Is the battery just for backup?
If I have to buy a new unit will the ST799 fit with no problems. (7 Day Timer)

Hope some one can help.
Thanks.

 

[gas4you]

Battery is just for back up. Unfortunately no longer availble to replace. New ST699's have battery built on PCB

 

[pannierstan]

I still have a battery for the old St699 on the van but I dont think it will save you in this instance.
The clocks going dolally (technical term)
Replace it with whatever you have if you can do the wiring

Stan

 

[gas4you]

New ST699 will plug straight onto back plate. Not certain whether 799 uses same back plate, never fitted one.

 

[ORGANIC]

Thank for every ones help I will have a look for a new ST699 or ST799 if it will fit.