Drayton Digistat SCR - appears to have been by passed

[M7R]

just stripped the main power unit to check wiring in there, and then took the boiler apart to get to the power block in there and found this!!!

no wonder it doesnt work!

heres how the install says it should be wired:

However I will now post a pic of the main power box as it does not go to the right place in there it seems

 

[M7R]

The black block is port 56 btw,

the 1 connected wire from that goes down to port 12 which says BLR

traced wire back from block 56 has 1 black dot, I ma now tracing the others to see where they go:

 

[M7R]

the timer is a Draton LP112 btw,

I have just traced the wired back from the main power box, from ports 2 and 3, and they go into the SCR control box ports 1 and 3, the correct way round for com and call,

so I guess the problem is between the timer / controller and the SCR,

I can happly trace any wires you want if you tell me what to trace, as something doesnt seem right to me, but it could be correct.

here is the wiring between the controller and the thermostat SCR,

Controller end:

SCR Thermostat end:

the wires from 3 and 4 on the controller end are connected to the main live, neutral and earth on the power board

 

[M7R]

oh and now I have fired all the system back up, the SCR wont go into pairing mode, it still has the red "Alarm" LED lit all the time.

and there is no demand for central heating.. ie the timer says it is ON, however the valve keeps the supply to the rads switched off... but if I press over ride then valve moves and the system starts to heat the rads

 

[M7R]

anyone got any ideas? as I would like to get it sorted this weekend if I can, then I can move on the other issue of noisey pump and air in the system

 

[doitmyself]

Questions about white cable marked with a black dot

Does the other end of brown wire connected to terminal 12 go to LR on the boiler?

What are the two ends of the blue wire in this cable connected to?

 

[M7R]

yep the other end connects to LR on the boiler,

and the blue wire is not connected to anything at either end.. the only wire in that cable used is the brown one.

 

[doitmyself]

the SCR wont go into pairing mode, it still has the red "Alarm" LED lit all the time.

Then either the two parts are incompatible (different frequencies) or one part is faulty

if I press over ride then valve moves and the system starts to heat the rads

Presumably you mean the override on the SCR. If so, then the SCR and boiler are correctly wired to the junction box.

Did you purchase a new set - controller and SCR - and did you change both parts?

 

[M7R]

the parts are both from a set, unused before me, both should be the same freqencies

Yes I mean override on the SCR, however if you read the SCR comission guide it states that before a thermostat is paired with the SCR you need to check it is working, this is done by turning the power back on to everything, then once the override button is pressed the boiler should fire... in my case the boiler fires before the over ride is pressed.

I will be chasing the wiring again with my friend who is an electriction on sunday, as when I traced the wiring of everything back something does not seem right somewhere.. the way it is working the SCR is a redundant junction box to some degree.


although I have noticed that inside the stat the sticker says model no: 30002 which is the wired version?! and there is no aerial pic on the lcd display which the instructions say there should be..

I am half tempted to just ditch it and get a new stat and controller:

Siemens RDH10RF/SET-GB Digital Room Thermostat

or

Hortsmann HRT4-ZW Wireless Room Thermostat

any views on these?

 

[doitmyself]

the parts are both from a set, unused before me, both should be the same frequencies

But did they come together in a sealed box?

I have noticed that inside the stat the sticker says model no: 30002 which is the wired version?! and there is no aerial pic on the lcd display which the instructions say there should be

Sound as if you have been sold a pup! Get your money back

I am half tempted to just ditch it and get a new stat and controller

If you are just looking for a wireless thermostat, the Honeywell DT92E is the one to go for.