please HELP with Vaillant 428 on Y plan Honeywell System

[krazaq]

I had a new boiler installed by a gas fitter, Vaillant 428. He also installed 3 Way valve and a new Cylinder and a new pump and a room thermostat. All honeywell y plan pack.

I'm an electrician and I thought I would wire it up according to the Y plan Wiring Diagram. But the problem is according to Vaillant hand book the Pump should be wired to the Pump terminals in the boiler, but the Y plan connects the pump to the mains going to the boiler.

Does the boiler need a separate fixed feed for mains, or can i use the diagram below to wire it up.

http://www.honeywelluk.com/Documents/All/pdf/940.pdf.

At the moment i have done all the wiring according to the diagram in pdf above, but don't want to switch it on till i'm sure.

Please help.

 

[kevindgas]

you need a permanent live to L terminal use term 4 for the switching from timer/room stat
wire the live from the boilers pump connection direct to the pump, doesn't matter about Neutral/Earth you can take these from the wiring centre or the boilers pump connection

 

[krazaq]

Please just confirm,

i need to connect the live from the boiler to the pump. right? and don't bother with connecting the pump to the 10 way junction box unless i want the neutral and earth which i can take from the boiler too? (Basically connect pump to the pump connectors on Vaillant 428)

And provide live to boiler from mains and not through the junction box. So how would i have any connection between the junction box and other instruments that are connected to the junction box.

 

[ServiceNumpty]

You need a perm live into the boiler, the pump is connected into the boiler, and the orange from the 3 way valve is connected into the switched live in the boiler.

 

[kevindgas]

on a y plan terminal 1 in the wiring centre should be perm live
terminal 8&9 are usually linked

take a live to the boiler live from term 1
take a live (switched) to terminal 4 on boiler from 8/9

wire the rest as a standard y plan except the pump live which is on 8/9 normally this should instead be from the boiler pump live connection (you can go direct or wire via terminal 10 in the wiring centre) the pump neutral / earth are there if required but aren't necessarily used as you can wire the pump L/E from term 2 & 3 in the wiring centre if its easier.

 

[mickyg]

i assume thats a 28mm 3 way valve?

 

[kevindgas]

i assume thats a 28mm 3 way valve?

 

[Youllneverguess]

28kW through a 22mm three way valve?

Not good really.

 

[krazaq]

on a y plan terminal 1 in the wiring centre should be perm live
terminal 8&9 are usually linked

take a live to the boiler live from term 1
take a live (switched) to terminal 4 on boiler from 8/9

wire the rest as a standard y plan except the pump live which is on 8/9 normally this should instead be from the boiler pump live connection (you can go direct or wire via terminal 10 in the wiring centre) the pump neutral / earth are there if required but aren't necessarily used as you can wire the pump L/E from term 2 & 3 in the wiring centre if its easier.

Now i get it. pump directly connected to the boiler.

Boiler connected through the junction box from 1, 2, and 3 and switched live (orange) from terminal 8.

i have ran one wire from the junction box to the boiler. so i will use that wire for pump, which is next to the junction box, except earth as i will use this as the Switched live from terminal 8 to boiler terminal 4. and provide the boiler with a separate mains supply with switch.

This should work right? The only problem is i will be using an earth as switched live....is that ok or i can just sleeve it i suppose.

 

[Youllneverguess]

The only problem is i will be using an earth as switched live....is that ok or i can just sleeve it i suppose.

Thought you were an electrician?

Having two separate power supplies is also not a good idea.

Why didn't the gas fitter wire this up?

So much for Part P.

 

[Agile]

Do you really need a 28 kW boiler?

Do you live in a six + bedroom house?

Tony

 

[flameport]

This should work right? The only problem is i will be using an earth as switched live....is that ok or i can just sleeve it i suppose.

If you really were an electrician, you would know that using the green/yellow core as a switched live is NOT acceptable under any circumstances, sleeved or not.

If the pump is separate from the boiler, the boiler connects to the wiring centre using a 5 core flex.
A 4 core flex can be used if the pump is integral to the boiler.
If no 5 or 4 core flex available, two 3 core flexes can be used.

The wiring diagrams in the Honeywell manual are literally decades old, and were drawn when boilers contained a pilot light, gas valve and almost nothing else.

 

[Agile]

Its odd that your boiler installer did not wire the system as most do.

Perhaps you chose to do it yourself?

In that case one would have expected that you are half competent to wire it up and in addition I would have expected that you would have know that all boilers now need a permanent live and power the pump from the boiler.

Tony

 

[mickyg]

haha electrician my @rse. So how was the boiler commissioned if it wasn't wired up?
Look up S53 I got a hunch it might be your nemesis before long

 

[D_Hailsham]

Here are a thousand words! (follow the pump over run option)

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