Drayton RF SCR Questions

[D_Hailsham]

This is the second SCR we have had and both have done the same thing.

Then we have to consider the possibility that the boiler itself is causing the problem.

1. Are there any Fault Codes (FXX) appearing?

2. What Status Codes appear when the problem occurs? (Press the - key for more than five seconds until you see a flashing S followed by a number.)

It should go through a sequence of codes.

The Installation Manual may help.

 

[Steve1138]

I did think that the boiler could be activating the SCR (which was partially what made me suspect the connections) but Drayton reckon that's impossible and the SCR does not work that way.

I think I will have to get on to them again.

 

[D_Hailsham]

I did think that the boiler could be activating the SCR.

I wasn't suggesting that the boiler activated the SCR - can't see how it could - but that the boiler was self-lighting, independently of the SCR.

Does any SCR light turn on when the boiler lights when it shouldn't?

In your original post you said: I can get the green light on the Drayton SCR receiver to come on and the boiler makes a noise but the radiators do not come on.

Now you are saying: Since moving in we have had problems with the SCR activating the heating whenever it likes (ie when the control is not calling for heat)

They are contradictory! Which is it?

 

[Steve1138]

Yeah, the original thread was a slightly different problem which I have now solved.

The issue now is that the light on the SCR comes on and the boiler fires for no apparent reason, even if I take the batteries out of the +3rf in the living room.

 

[D_Hailsham]

Yeah, the original thread was a slightly different problem which I have now solved.

But the new problem could be related to the old. How did you solve the old problem?

The issue now is that the light on the SCR comes on and the boiler fires for no apparent reason, even if I take the batteries out of the +3rf in the living room.

You need to find out why the light is coming on. (Obvious, I know. )

The light must be connected to terminal 3 of the SCR so it only lights when the internal switch closes, connecting 1 to 3. So you should get: L feeds 1, which feeds 3 (via the internal switch), which feeds boiler R.

Now, what would happen if something in the boiler reversed the process (Don't forget that the boiler has a permanent supply): Boiler R feeds 3. The green light would still come on, but the switch in the SCR would be open.

Disconnect the link between L and 1 on the SCR backplate. You will still get you hot water, but you should not get any heating. If the heating still comes on at random times, the fault must be in the boiler. If the problem goes away (you get cold ), there must be a fault in the SCR.

If you still suspect a faulty SCR, reconnect the link between L and 1 and disconnect the wire to 3. You won't get any heating, but you will be able to check if the SCR still comes on when it shouldn't.

PS Take the batteries out of the control unit to eliminate that source of the problem.

 

[Steve1138]

The problem before was that I could get he boiler to turn on using the controls but the rads would not heat up, I eventually found a stopcock in the bathroom that had been closed and when I opened it up the rads filled with water and we had heating.

Now though its a case of the heating always coming on and off throughout the day, even if the controls are not calling for it. The only way to stop it is to turn off the heating on the boilers controls but the the pressure drops (see another of my threads)

I have disconnected the link between L and 1 and taken the battery out of the receiver so will wait and see what happens. Will let you know.

Thanks

 

[Steve1138]

Ok, its actually doing something now which it has only seemingly started doing in the last few days, which I forgot to mention.

The red "receiving" light on the SCR is just flashing at a slow steady rate, cant find anything about what this means in the manual.

If it flashes rapidly then it is receiving an instruction from the SCR and if it remains on then there is a fault but it now just flashes slow and steady.

Really starting to hate this heating system in this flat!

 

[Steve1138]

It seems that the red flashing light may have something to do with removing the battery from the transmitter.

I just put the battery back in the transmitter and the SCR cleared itself and the green light came on (the transmitter was calling for heat though) I switched the transmitter off (leaving the batteries in) and the green light on the SCR went off.

I'm sure the flashing red light is not something that had happened prior to the last few days when the batteries were removed so perhaps the fault with the SCR has somehow corrected itself and it is now doing what it is supposed to do.

I'll keep an eye on whether the SCR comes on over the next dew hours though with the transmitter switched off.

 

[Steve1138]

It seems that the red flashing light may have something to do with removing the battery from the transmitter.

I just put the battery back in the transmitter and the SCR cleared itself and the green light came on (the transmitter was calling for heat though) I switched the transmitter off (leaving the batteries in) and the green light on the SCR went off.

I'm sure the flashing red light is not something that had happened prior to the last few days when the batteries were removed so perhaps the fault with the SCR has somehow corrected itself and it is now doing what it is supposed to do.

I'll keep an eye on whether the SCR comes on over the next dew hours though with the transmitter switched off.

Right, scrap that theory, the red light has just started its steady flashing again!

 

[Steve1138]

Another update, the link between L and 1 is still disconnected, the batteries are back out of the transmitter and the green light on the SCR has just come on but the boiler has not started the CH.

The green light is currently on with the steady flashing red light under it.

 

[D_Hailsham]

I'm thinking that the boiler itself may be interfering with the SCR.

The picture, in your other topic, shows the SCR on the right side of the boiler and fairly close to it. The Installation Instructions, which you say you have, do not recommend locating it on this side and also say it should be at least 30cm (1ft) from the boiler. Might be worth moving the SCR to the right side of the boiler to see if it has any effect.

As for the flashing lights, the instructions tell you how to check the signal strength and how to commission the system.

 

[Steve1138]

I'm thinking that the boiler itself may be interfering with the SCR.

The picture, in your other topic, shows the SCR on the right side of the boiler and fairly close to it. The Installation Instructions, which you say you have, do not recommend locating it on this side and also say it should be at least 30cm (1ft) from the boiler. Might be worth moving the SCR to the right side of the boiler to see if it has any effect.

As for the flashing lights, the instructions tell you how to check the signal strength and how to commission the system.

Id often wondered about the SCRs location as you are correct, the exact location the manual says that it should not go is exactly where the previous owners fit it.

Last night I removed it from the cupboard and screwed it onto the kitchen wall outside the cupboard but it is still doing the exact same "new" problem. It will work temporarily but then the red light will start flashing steadily untill I manually adjust the temp on the transmitter.

I have done the signal strength test it seems fine. i also changed the batteries in the transmitter in case a steady flashing red light meant low bateries but stil no joy.

I can't find anything anywhere explaining what a steady flashing red light means.

 

[D_Hailsham]

Flashing light may mean that the Digistat and SCR are not communicating properly. Have you tried recommissioning the Digistat and the SCR?

1. Turn off the power supply to the Digistat SCR (receiver unit)
and leave for 5 seconds. Remove batteries from Digistat
2. Turn on power to SCR unit and check red light is on.
3. Press override button No.2 and check the green light comes
on and boiler fires.
4. Press & hold down button No.1 (Keep depressed), then
press No.2 and keep depressed. The Red LED light will flash
a couple of times and then it will go out
5. Now release both the buttons – the two LED lights should
come back on
6. Get the Digistat+2RF/+3RF unit and stand two metres away
from the SCR unit with the Digistat+2RF/+3RF unit in your hand.
7. Fit the batteries.
8. The Red LED light on the SCR will now flash for approx. 7
seconds.
9. This confirms that the radio signal is being sent and
received.
10. The Digistat+2RF/+3RF and the SCR are now successfully
linked by a dedicated RF address.

If it still fails to work, phone Drayton on 0845 130 7722.

 

[Steve1138]

Yeah, I think I have done that several thousand times up to now (and that's not an exaggeration either)

Drayton have been scratching their heads over this problem for a couple of months now.

Think perhaps I should just look into getting a different control unit.

 

[D_Hailsham]

Think perhaps I should just look into getting a different control unit.

Wouldn't blame you.

If you do, get a Honeywell CM927.