programmer swap no no hot water!

[Paul Thompson]

Hi all,
I've just swapped over programmers from my defunct honeywell ST699 to their ST9400C. My system includes a V4073 mid position valve and an L641 Cylinder Stat.
The instructions showthe replacement wiring from one unit to the other which i have followed.
Problem! The CH, lights up on the programmer and the boiler fires up but although the Hot Water lights up on the programmer, it doesn't fire up the boiler? I've tried turning up the cylinder stat to induce the boiler to start but to no avail.
Any ideas?
Paul.

 

[Mbear]

Hi all,
I've just swapped over programmers from my defunct honeywell ST699 to their ST9400C. My system includes a V4073 mid position valve and an L641 Cylinder Stat.
The instructions showthe replacement wiring from one unit to the other which i have followed.
Problem! The CH, lights up on the programmer and the boiler fires up but although the Hot Water lights up on the programmer, it doesn't fire up the boiler? I've tried turning up the cylinder stat to induce the boiler to start but to no avail.
Any ideas?
Paul.

Is there a wire at the 'Hot Water off' terminal on your new programmer?

It sounds like you've maybe wired it incorrectly mate. Did it fire for HW before you replaced the prog?

 

[doitmyself]

Have you removed the link between L and 5 and 8 on the back plate? It's not required for theST9400.

 

[Paul Thompson]

Mbear, thanks for the reply, The wire for the HW off on the ST699 was at terminal 7 and the new instructions say to wire this to terminal 1 on the ST9400 which i have done. It did fire on the old programmer (the old programmer was replaced because the timer functions went mad and i had to switch it manually)

Thanks for the reply Doitmyself,
The backplate has been replaced (part of the new ST9400) as they differ in size. What remains in my old ST699 on my desk is the link between 5 and 8 as you rightly point out it's not needed on the ST9400.

 

[Mbear]

Do u know how to fault find and trace voltage on ch systems?

Also do u have a fluke meter?

Try this...
turn power off and prove dead,
Remove the facia from the new prog,
get a spare piece of wire and strip bare at each end,
use this wire to wire the 'live terminal' together with the 'hw on terminal',
stand back and turn power on,

if boiler fires for hw then there may be a fault with the new prog unit or you've maybe not set it or wired it correctly bud

 

[Paul Thompson]

Unfortunately not on both counts mbear. i'm wondering if the ST9400 is faulty? then again something else may have caused the ST699 to go awol?

 

[Mbear]

Unfortunately not on both counts mbear. i'm wondering if the ST9400 is faulty? then again something else may have caused the ST699 to go awol?

have a bash at the 2nd part of my post mate

 

[Paul Thompson]

Mmmm Stand back eh! what could happen? That looks like i'll be putting a live feed to the cylinder stat, is that what you meant?

 

[Mbear]

Mmmm Stand back eh! what could happen? That looks like i'll be putting a live feed to the cylinder stat, is that what you meant?

Nothing should happen, just meant the terminals will be exposed and live, basically don't touch. Safety first and all that

yeah, basically it's called 'linking out', it means u r taking the prog out of the equation. If it fires then u can be sure there's summit not quite right with the prog. U can link out lots of things in ch to prove if components are faulty or not

 

[Paul Thompson]

Nothing should happen, just meant the terminals will be exposed and live, basically don't touch. Safety first and all that

yeah, basically it's called 'linking out', it means u r taking the prog out of the equation. If it fires then u can be sure there's summit not quite right with the prog. U can link out lots of things in ch to prove if components are faulty or not

Thanks for the useful info I'll give it a go

 

[bmcglone]

Did you manage to fix it. I have same problem. Lights up, but no one home.

 

[bmcglone]

Put the wrong wire in 4. Hot water working heating does not work.