"Charlie" wrote in message
om...
Hello,

I have a Honeywell wiring box into which all the components of my CH
system are wired. In the last couple of days the 2A fuse in this box
has blown (twice) and a 3A one also blew - obviously I have a problem.

The pilot light is still on. There are no signs of leaks. Presumably
it could be any of the components but presumably likely to be the pump
or the motorised value.

I've had this twice and both times it was a failing synchron motor (not yet
failed) in the zone valve. Might be an idea to get a spare synchron motor
if you havn't got one. Were fairly cheap from BES, now you have to pay
postage.

I would first check if you have separate mains feeds to boiler and wiring
box. If separate I would not suspect boiler or pump initially. The
intermittency may just be due to the actual current being drawn. Don't
have the tables to hand but depending on the actual current the fuse may
take some time to blow. If you are confident (and competent) I would
suggest inserting a test meter on ac Amps in series with each load (zone
valve(s), pump, boiler etc). Obligatory health warning - switch-off while
connecting. What I might do in this situation is to fit a 13A plug (3A fuse)
to the feed and plug into a 30mA RCD. Healthy readings should be nowhere
near 3A. OK, won't work if it is genuinely an intermittent, but I would
suspect not.

Cost of Plumber? Sorry d-i-y here, you can buy a lot of pumps, zone valves,
test meters etc for the cost of a plumber.

Alan