Replacing heating programmable timeswitch

[liamconnolly]

Hello, i'm replacing my broken Thorn EMI programmer (believe based on a Honeywell 42003744) with a Sunvic i picked up at B&Q.

It is for a boiler feeding heat and h/w.

Looking for advice on the wiring terminals.

Basically, the Thorn had 8 terminals and the Sun only has 6

The wiring diagram on the Thorn is as follows:

H/W - terminals 8, 7, 6 are for COM, NC & NO respectively
Heat - terminals 5, 4, 3 are for COM, NC & NO
N and L obviously

The Sun is:

Terminals 1 (H/w off); 2 (heat off); 3 (H/w on); 4 (heat on) + N & L

The Sunvic is a dual channel so i bought the right one.

Just wondering which i can double up on and which must remain separate!

Thanks in advance,

Liam

Liam

 

[electronicsuk]

The wiring diagram on the Thorn is as follows:

H/W - terminals 8, 7, 6 are for COM, NC & NO respectively
Heat - terminals 5, 4, 3 are for COM, NC & NO
N and L obviously

The Sun is:

Terminals 1 (H/w off); 2 (heat off); 3 (H/w on); 4 (heat on) + N & L

On your old programmer, NO is the equivalent of call for heat, whereas NC is heat off. Both com terminals had probably been linked to L on the old programmer, but it would appear this is done internally on the replacement you have purchased.

So:

Sun terminal 1 = Thorn terminal 7
Sun terminal 2 = Thorn terminal 4
Sun terminal 3 = Thorn terminal 6
Sun terminal 4 = Thorn terminal 3

 

[liamconnolly]

Thanks Matthew, hot water, heating and happy family now restored