Honeywell Programmer blowing fuses

[Peter]

Hi,
I've got a Honeywell programmer controlling my central heating and hotwater.
The power to it comes from a swiched fused spur. This is fitted with a 3A
fuse.
About every two weeks the 3A fuse blows.

I'm assuming the programmer is faulty, but before I replace it, could there
be anything else causing the 3A fuse to blow?

Thanks
Peter

[Andrew Gabriel]

Post by Peter
Hi,
I've got a Honeywell programmer controlling my central heating and hotwater.
The power to it comes from a swiched fused spur. This is fitted with a 3A
fuse.
About every two weeks the 3A fuse blows.
I'm assuming the programmer is faulty,

Why?

Post by Peter
but before I replace it, could there
be anything else causing the 3A fuse to blow?

Boiler, pump, diverter valve, thermostat, interconnect cabling...

[Peter]

Ahhh...not as easy I a first thought.
I didn't realise the mains power to the programmer also fed other parts of
the system. I assumed (wrongly) that the 3A spur only supplied the
programmer itself!

Post by Andrew Gabriel

Post by Peter
Hi,
I've got a Honeywell programmer controlling my central heating and hotwater.
The power to it comes from a swiched fused spur. This is fitted with a 3A
fuse.
About every two weeks the 3A fuse blows.
I'm assuming the programmer is faulty,

Why?

Post by Peter
but before I replace it, could there
be anything else causing the 3A fuse to blow?

Boiler, pump, diverter valve, thermostat, interconnect cabling...
--
Andrew Gabriel

[Ed Sirett]

Post by Andrew Gabriel

Post by Peter
Hi,
I've got a Honeywell programmer controlling my central heating and hotwater.
The power to it comes from a swiched fused spur. This is fitted with a 3A
fuse.
About every two weeks the 3A fuse blows.
I'm assuming the programmer is faulty,

Why?

Post by Peter
but before I replace it, could there
be anything else causing the 3A fuse to blow?

Boiler, pump, diverter valve, thermostat, interconnect cabling...

With electric faults on heating systems the pump is centre stage and then
some unless the boiler is leaking water into its controls.

[Dave Liquorice]

Post by Peter
I'm assuming the programmer is faulty, but before I replace it,
could there be anything else causing the 3A fuse to blow?

Yes, anything fed via the programmer, like the room and tank stats,
the pump, the boiler or any bit of rodent nibbled wiring betwixt all
that lot.