Digistat SCR not firing Optia HE18 boiler

14 May 2009
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United Kingdom
Morning all,

Just moved into a new house and I am having a problem with our central heating.

The Digistat RF1 wireless controller appears to be working correctly (temperature shown on display, fire symbol appears when temp drops) and it is communicating fine with the SCR (solid green light appears when there is a demand for heat).

However, when the green light is on the boiler is not firing. There is a Potterton EP 2000 connected to the SCR controller and we have this set to 24hr for both CH and HW. HW works fine and is firing the boiler when needed, but we are not getting any HW.

Previous owners never had any trouble with the system. Boiler is about 18 months old.

I have gone through previous posts and tried changing batteries and reconnected the RF1 to the SCR and this part looks to be working correctly.

Does anyone have any ideas?
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Digistats are known to cause problems, and Ideal is not exactly the best boiler on the market either.
Are you able to safely disconnect the external controls and bridge the connectors?
Are you referring to the connections under the SCR?

If I remove the cover there are 6 connections; N, L, 1, 2, 3 and 4.

There are cables going into N (blue), L (brown), 1 (black) and 3 (white).

Not sure how to bridge the connections - can you advise?
...Not sure how to bridge the connections - can you advise?

I would say that this sufficiently indicates you can not do this safely.
I recommend you get a pro to look at this, both from a safety point of view and also as it is quite possible you do more harm than good with diy.
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Good point.

I work in IT so now I am past the point of 're-boot' and hope for the best I am completely lost.

I will make sure there is no dust or rubbish affecting the connections and then leave well enough alone.

Thanks for your advise.
It is working again now!

Must have been something obstructing the connections. Looks like the reboot still rules!

Thanks again.
When you get somebody out, make sure they work on a no-cure,no-pay basis.
Too many fools out there that don't know what they are doing.
Don't fall for the "looks like the pcb, that is 350 quid".
With the right knowledge and tools, it will take 5 minutes to prove whether it is the boiler or the controls.
If it is the controls and parts need replacing, chuck all the old stuff and replace it with a programmable roomstat; much better value for money.

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