In article ,
Robin .@. writes:
Hullo uk.d-i-y world...

I have inherited an old Vaillant VC Gas boiler. It works OK, but the
'built-in' timer control is broken and no-one I know wants to touch it.
It's all going to be ripped out in about 18 months, so I want to do a
quick fix to get a timer control.

The boiler connects to the mains electric using a switch box. See the
picture at:

http://www.flickr.com/photos/7204575@N04/2852870557/

The switch box on the mid left is wired into the double socket above it.
The wire that comes out of the bottom of the switch box goes into the
boiler.

Would there be any issue if I removed the switch box and put a regular
plug on the wire instead?

A couple of issues...

The socket should be an unswitched one if it has a fixed
gas appliance connected to it. Also I'm assuming the spur
is already wired correctly into it's supply.

The boiler may not like being routinely switched simply by
turning its mains supply on and off. That wouldn't allow a
pump run-on function to work, or any built-in frost protection,
or pump exerciser. (I don't know if your boiler has any of
these features.)

If I did this I could put a timer on the plug (X10), insert into socket
and presto, I've got the boiler on a timer.

Your boiler probably has a connection block to which a
timeswitch is supposed to be connected. Do you have the
installation manual for it (it's supposed to be left with
the boiler after installation and when a house changes
hands).

Aside: I had this all apart earlier today, the switch box had a 13amp
fuse, but the old manual for the Vaillant says the fuse should be 3amps,
so I've replaced the fuse and its working ok. This is right isn't it? A
gas boiler doesn't draw a lot of current, does it?

That's correct.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]