Vaillant ecoTEC and the Honeywell T6360B

19 Feb 2009
Reaction score
East Lothian
United Kingdom
Hello Fellas, Hope some one can help me just a tad. I know I am so close but some time I cant see the wood for the trees.

links for diagrams
stat Controls/2.17 T6360.pdf
boiler (go to page 27)

I have a Honeywell T6360B and a Vaillant ecoTEC combi Boiler.
I have successfully connected the boiler to the mains supply and also fitted the vaillant plug and play timer. Now i am trying to install the external Honeywell T6360B thermostat.

The thermostat has 4 terminals plus an additional terminal marked earth
The boiler has a set of terminals number 3, 4 and 5 for connecting external controls such as a time switch and room stat. Terminals 3 and 4 are linked when the boiler is supplied (purchased). The instructions state that if external controls are used this link must be removed and the controls connected across terminal 3 & 4. Terminal 5 is an additional neutral connection for external neutrals such as from the anticipator of a room stat.

The stat diagram shows
L connected to Stat terminal 1
N connected to stat terminal 2 (anticipator)
N connected to stat terminal 3 (through the heating load i.e BOILER)

1- Has Vaillant kindly provided the BOILER terminals 3, 4 and 5 to allow connect direct to the stat?
2- If YES is this the correct wiring sequence
Boiler Terminal 3 acting as a LIVE going to stat terminal 1
Boiler Terminal 4 acting as Neutral going to stat term 3
Boiler Terminal 5 acting as Neutral going to stat term 2

If these boiler terminals are a convenience could I wire up directly from the switched double pole isolator? I only ask as to better my understanding of the circuits.

Thanks kindly for all your help

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No, If you read your post you will realise boiler terminals 3 and 4 if linked already will be dead short, your nearly there just think about it, go on I have faith in you ;)
Terminal 3 is live out to the stat, terminal 4 is switched live back to the stat.
BT = boiler terminal
ST = stat terminal

1- the existing dead short between BT3 & 4 is required inorder for the boiler to produce central heating.
2- Vaillant installation manual correctly states "if external controls are used, this link must be removed, and the control connected ACROSS terminal 3 & 4.

So therefore the room stat is mearly taking the place of the link between BT3 & BT4

Hence here is my new connection sequnce
BT3 connected to ST1
BT4 connected to ST4
BT5 connected to ST2
Boiler earth to Stat earth

but this is not consistent with the Honeywell stat wire diagram?

So then assuming Honeywell wiring diagram is correct I am back to
BT3 connected to ST1
BT4 connected to ST3
BT5 connected to ST2

Honeywell installation book also states that a neutral connection must be made to St2 when heating load is less that 6amps. Vaillant operates only on a 3 amp.

I am missing something fundamental so i cant be sure right now. :S
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Connect as follows:

ST1 to BT3
ST2 to BT5
ST3 to BT4

ST4 is not used.

Job done.

BT3 provides the live to the stat ST1, which is switched back via ST3 to BT4, switched live. BT5 provided the Neutral connection to ST2.

Don't forget that one side of the "heating load" is Live and the other side Neutral. The Honeywell diagram is a bit confusing as it looks as if there are two neutral connections to the stat.
OKay so i was right then!!!!!

thanks guys thanks very much

I off to wire it up.

now where did i put that multi meter :)
I can see my connections in the first instance were correct but i see my terminology was incorrect. Thats where the confusion from the Honey Well diagram comes in to play.

Can any one explain to me in a basic sense and in a general term what is the difference between the live and neutral wires. Is it to do with AC current travelling back and forth in the circuit . 50hz means every second the travel of current changes 50 times?

FOr all this knowledge it is really great of you guys


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