honeywel st94000c

[illgiveitago]

hi can anyone help with my issue

i have the above 7 day timer - and i am struggling with wiring it up so the hot water works



currently i have the following wiring


N L 1 2 3 4

blue Brown empty empty red black


i believe black in CH on and this seems to bear out with the green light on and heating on
i thought red was HW on and put it in terminal 3 but it appears that when the control is "off" i get HW and when it is "on" ( ie green light lit) I get no hw


I only have 5 wires red black earth live and neutral

any help greatly appreciated

 

[Dan Robinson]

Terminal 3 is HW on.

 

[illgiveitago]

Thanks Dan


I have the

brown in L
blue in N

earth in 1

red wire in terminal three Hw on
Black wire in terminal 4 ch on


the only way i can get it work now is for the earth in terminal 1

with this combination the ch goes on/off appropriately

however now the HW is on when the timer say off and off when the timer says on

any help greatly appreciated

 

[D_Hailsham]

Do you have a valve which looks like this - three ports?

View media item 5946
If so, your "earth wire" is not an earth wire, it is being used to carry voltage (naughty!).

 

[D_Hailsham]

however now the HW is on when the timer say off and off when the timer says on

Missed this bit!

Swap the wires in 1 and 3.

 

[illgiveitago]

thanks i'll try that - but are you saying that earth in terminal three is a dodgy way of doing things?


I am worried that somethign may go wrong wiring fire or something of that ilk

should i be worried and get a qualified plumber in ?

 

[illgiveitago]

Also yes i do have a 3 port valve just like the one pictured

 

[D_Hailsham]

thanks i'll try that - but are you saying that earth in terminal three is a dodgy way of doing things?

Its the cheap and lazy way of getting another wire if an earth is not necessary, which is the case for the ST9400C.

The correct way is to use a cable with the correct number of cores, even if it means leaving the earth wire unused. So, in your case you would need a five core or a five core plus earth.

I am worried that something may go wrong wiring fire or something of that ilk

Nothing to worry about.

Terminal 1 is live when the HW is OFF and Terminal 3 is live when HW is ON, so you already have 240 volts running through the "earth wire" when HW is OFF. It's just that the "earth wire" should be connected to terminal 3 and the red wire to terminal 1.

 

[illgiveitago]

This is now sorted - i was almost there - it has taken me a couple of weeks of studying manuals etc but i just couldn't get my head around the earth being a Live, and it totally threw me

Once again THANK YOU