Spoke to Worcester Bosch a few months back and was told I can wire my UFH pump directly in to my 40CDi boiler, so that when the internal pump fires up to circulate the water, the UFH pump fires up at the same time.

Have been trying to get my local WB installer to do the work, but am having difficulties getting them booked in due to being very busy. Naturally the ground floor is pretty cold at present.

As a guy who turns his hand to anything, I have been checking it out myself and see the internal pump has your typical T&E supply and then 3 additional wires (black, white and purple) that control it. The external circulating pump of my UFH has the T&E power supply only.

So... query to all WB installers/servicing guys or people just in the know... how will it be expected that the guy I get round to do the 5 minute job will wire it up?

Just out of curiosity that is, so I can make sure he does it right! :-)

What do each of the black, white and purple control wires do?

In article ,
Cordless Crazy writes:

Spoke to Worcester Bosch a few months back and was told I can wire my
UFH pump directly in to my 40CDi boiler, so that when the internal pump
fires up to circulate the water, the UFH pump fires up at the same
time.

Have been trying to get my local WB installer to do the work, but am
having difficulties getting them booked in due to being very busy.
Naturally the ground floor is pretty cold at present.

As a guy who turns his hand to anything, I have been checking it out
myself and see the internal pump has your typical T&E supply and then 3
additional wires (black, white and purple) that control it. The external
circulating pump of my UFH has the T&E power supply only.

The internal pump in the WB is probably a 3-speed pump. Instead
of a selector switch, the separate wires are taken back to the
control board so the boiler can change the speed itself, to get
optimum return temperature for condensing operation. This is how
my Keston works anyway.

So... query to all WB installers/servicing guys or people just in the
know... how will it be expected that the guy I get round to do the 5
minute job will wire it up?

Not familar with that boiler, so can't comment in detail.
Some boilers have a connection for an additional external pump.
Another option would be to run it directly from the room stat
call for heat output, if that runs at mains voltage.

--
Andrew Gabriel