DIYbanter - View Single Post - central heating on when it should be off?

Steve

wrote:
I was expecting this to be a Honeywell 4073 mid position valve before I
saw your photo. It still 'looks' like one but clearly isn't.
It is getting on for 15 years old - might it be an earlier model?

Generally, the motorised valves with a replaceable actuator have a
dimple on the top of the casing. it is not clear from yours whether you
have this or not.

There is a dimple on the top of the casing, just above the out of focus
screw you can almost see at the top centre of the "other end" photo -
with that, and the info about head replacement on the casing, I hope I
am safe in assuming that it can be replaced. Still need to figure out
if that's what needs replacing though. Are we talking about a lot of
money here?

Anyway, the problem is one of two things; mechanical or electrical. In
order to diagnose the fault you will need a multimeter and will have to
poke around in the wiring centre. An electrical neon screwdriver will
not be sufficient to do this.

Are you confident of not electrocuting yourself?

I am never confident around live electrics - that may be why I have
avoided electrocution so far. The trouble is I don't have a multimeter
and I almost certainly wouldn't know how to use one.