In message , Owain
writes
altheman wrote:
hello, this may a stupid question to some but to me it is not...i have
recently moved into another house...the current central heating system is
run with a ...RANDALL 4033 PROGRAMMER....it has 2 switches...one that
controls the hot water...the other controls the central heating (
radiators)...what i can gather the PROGRAMMER is approx 20yrs old...but
still seems to work perfectly...my question therefore is....do i need to put
both switches down to run just the central heating ?..for just the hot
water i only put 1 switch down...but someone said that to run the radiators
i had to put both switches down...even if i only wanted radiators on and NOT
hot water,we also have a BAXI gas fire with a back boiler ( if that is of
any importance)..many thanks in advance


It depends on how the system has been plumbed and wired. Usually (and
I'm not familiar with that particular programmer) if there is no
heating-only option then the switches are interlocked so if you put the
heating on the hot water switch is also moved to on.

On my programmer in the new house the switches aren't interlocked, not
sure if they were/should be/could be though.

Put the heating switch on and see what happens. If the boiler starts
firing on-and-off then the call for heat is reaching the boiler but not
running the pump, in which case either the switches should be
interlocked or the system replumbed/wired to prevent this happening.

But hat doesn't happen, the [pump just runs in heating only mode.
--
Chris French