Drayton Digistat SCR and RF1 playing up.

[chris1982]

Today our Drayton wireless controls (Digistat SCR and RF1) were playing up. While it is working now, after recommissioning the two units, I am puzzled about it.

1. The timer was on calling for heat,a subject to the thermostat of course, and the digistat receiver showed a call for heat, but the boiler did not come on and must have not come on for some time, before I noticed the house being cold. I then pressed the override button, but nothing changed at all. (The setup had been working correctly for more than three years, so I would think the connections are wired correctly). Throughout the midpoint valve was in the correct position, central heating only.

2. Why would re-pairing the sender and receiver have overcome the problem, when the receiver had already shown a call for heat? (And the batteries in the RF1 seem to have been fine)

3. Is it likely to be an intermittent problem, i.e likely to come back soon?

Curious to hear any insights and experiences.

 

[ianmcd]

could be a fault with the Mid position valve or the receiver, you wont know until it stops again, those receivers are not very reliable I have to say, even though the green neon illuminates the relay doesnt always click over

 

[chris1982]

Thanks. I changed the midpositioning valve head three years ago, whereas the receiver is much older. I did have the feeling that the receiver's green LED was there, despite it not calling for the boiler to fire - after all the override button didn't do anything, not changing the green LED even.
If it stops again, is there a test I can do to verify it is indeed the receiver?

 

[ianmcd]

Thanks. I changed the midpositioning valve head three years ago, whereas the receiver is much older. I did have the feeling that the receiver's green LED was there, despite it not calling for the boiler to fire - after all the override button didn't do anything, not changing the green LED even.
If it stops again, is there a test I can do to verify it is indeed the receiver?

The receiver doesnt actually fire the boiler up as such, the receiver actually sends power to the mid position valve and it is the valve that sends power to the boiler to come on, if the green light comes on the receiver but the boiler is not firing, leave the heating turned on with the green neon illuminated, and switch on a call for HW (you might need to turn the Cyl stat up if fitted) if the valve moves to the mid position with both CH and HW calling then the receiver is fine , if the valve moves all the way over to HW only then the receiver is faulty

 

[Gasguru]

Check for 240v coming from the receiver...a common fault is the large capacitor inside the receiver failing and there's insufficient "power" to operate the relay. The caps are available on eBay if you're skilled with a soldering iron.

 

[chris1982]

Great, thanks. This afternoon I did bring the boiler on by manually calling for HW and putting the valve on manual CH, but didn't pay attention to the valve position when doing this. Will do next time.

 

[chris1982]

Thanks Gasguru. I will check the receiver output next time it fails. I would need to practice soldering though (long time ago did some in school), but it would help identifying the culprit.

 

[chris1982]

Hi guys,
Now a much bigger problem. The boiler doesn't seem to have any electricity at all. It's display does not come on, no matter what I tried with the programmer, room or cylinder thermostat. The connections in the wiring centre seem fine.
So is this a problem within the boiler, right? PCB?
It is an Ideal icos.

 

[ianmcd]

check the 3 Amp fuse in the fused spur, DO NOT, replace with a 13 Amp fuse

 

[chris1982]

I am not home right now, but know the programmer's display is working. The wiring is from the FCU to the wiring centre and from there to programmer (timer), 3-port valve, and boiler. Since the programmer seems to have power, would that not rule out the fuse?

 

[ianmcd]

I am not home right now, but know the programmer's display is working. The wiring is from the FCU to the wiring centre and from there to programmer (timer), 3-port valve, and boiler. Since the programmer seems to have power, would that not rule out the fuse?

Yes if wired correctly it would

 

[chris1982]

Ok, thanks. Will call in an expert.

 

[ianmcd]

There is also a fuse on the pcb inside the boiler, but the wiring for your boiler is done by a push fit plug, make sure you havent pulled that apart while working on other stuff

 

[chris1982]

So, an engineer came while I was still at work. He told the Mrs, the PCB was dead (and a high figure to replace it, though recommending a new boiler).
We were given three years ago by another engineer a used PCB (from a functioning boiler he replaced elsewhere) to keep as a spare part. The chap today first claimed this PCB we kept was a different board, then that he measured it and it was dead anyway.
I attach photos of the two. The numbers at the bottom are identical, so are they replacements for each other? And I got a multimeter, can I test myself whether the spare PCB (orange) is defunct?