wiring for new flexicom 15hx boiler

[petermack]

hello i am new to the site but i was wondering if anyone has the answer to my question. i am replacing a glow worm micron 50ff gas boiler in a open vent system with a glow worm flexicom 15hx boiler. the instruction sheet says that you must take the feed for the pump direct from the boiler yet the old system didn't. is this necessary or can i just wire the new one as the old boiler was wired?

 

[londonboy]

Yes this is necessary or glow worm won't touch boiler under guarantee.

Is this the boiler with the black plug in the bottom?
If so then you need a 5core at the boiler.

Live
Neutral
Earth
Switch line
Pump live

 

[petermack]

yes it has a black plug in box which goes underneath that you wire into. the connections are as follows:
live
neutral
earth
on one side of box

pump connections out:
live
neutral
earth
on the other side.
in the manual it shows two three core cables going into the box, one for each side. so this means i have to take a three core cable straight from the boiler to the pump and disconnect the existing wiring at the pump?

 

[properleckie]

further to what Petermack says, the reason is the new boiler requires the pump to 'run on' after boiler stops being 'called' to get rid off residual heat, boiler will have inbuilt overrun timer to do this.
as he says you only need to take the pump Live from boiler but for new installations the book shows ideal system with feed to boiler & feed out to pump direct,
regards,

 

[londonboy]

Its upto you, the manufacturers prefer you to take a seperate 3 core flex directly to the pump L N E.

I generally just use a 5 core cable all the way back to the airing cupboard and use it as I said above.

Make sure you put your wires in the correct terminals. Some of them are low voltage and its very expensive if you put 230v wires in 24v terminals!