Electrics question for new boiler

[flanajb]

I have had to purchase a new boiler which is being fitted shortly and I have a question regarding the electrical side of the installation. The existing boiler did not have a pump overrun and basically had a switched live / neutral and earth. These fed the boiler from a 3 amp switched spur. Now the new boiler requires a permanent live as well for the pump overrun. The spark who wired the house has put in a permanent live cable fed from the Honeywell unit so that is ok. The question I have though regards isolating these 2 connections. Do I require 2 isolation methods for the 2 lives. eg 2 separate switches. One for the permanent live and one for the switched live?

The switched live, obviously, becomes live when the CH or HW timer clicks on.

Sorry if I have not explained myself very well.


Thanks

 

[Fatboy]

I may be wrong but isn't this sort of adddtion to a circuit covered by the part p regulations?

 

[woodchip]

You cannot have two means of isolation.

In a normal setup the feed from the consumer unit goes into a fused and or switched spur. The load side of the spur feeds a "central heating wiring centre" (basically a glorified connection block). From here wires go to and from the programmer, boiler, stats pumps and motorised valves. Switching off the spur (or removing the fuse) isolates all of the system.

Hth

 

[flanajb]

Having done a bit more research I have discovered that sparks use a 3 pole fused fan isolation switch next to the boiler. This then ensures that you isolate both the permanent and switch live feeds coming down from the wiring centre when you switch the isolator off.

http://www.qvsdirect.com/excel-3-pole-fused-fan-isolator-switch-white

 

[gwaithcoed]

Hi flanajb, I have just fitted a new glowworm condensing boiler 18hxi. The pump over run is all sorted out with the boiler internal circuits as it was with my previous boiler. The 240 supply only need to be a double pole isolator with 3 amp fuse. The pump will continue to run until the boiler cools when the water circulates through the by pass circuit and when it is cool enough the pump stops.
Have a look at the installation manual and it should show you how it must be connected.

I am not certified "gas safe" although I have fitted quite a few boilers which I then get checked out with someone who is as I do not have the equipment to check the flue gasses

Alan.