Heating failure?

[robg172]

Hi all, I've got a Vaillant Ecotec Plus 831 combi linked to a Drayton Digistat.

I keep losing the central heating and the only way to start it again is to switch the plug on and off that powers the Digisat SCR (wireless receiver box). Trouble is, it works fine for a period (hours, sometimes days) then stops again.

Hot water is always ok even when the heating stops working, so I'm assuming I have a problem somewhere with the wireless system?

Help!

 

[ianmcd]

check where your receiver for your digi stat is installed and check against the manufacturers instructions things to look for are , is it within 300mm of the boiler ? is it near another electrical appliance fridge microwave etc? these will all cause the signal to be lost

 

[robg172]

check where your receiver for your digi stat is installed and check against the manufacturers instructions things to look for are , is it within 300mm of the boiler ? is it near another electrical appliance fridge microwave etc? these will all cause the signal to be lost

Hi, yes all installed ok. It has been working for nearly 5 years without fault. Only started happening recently.

 

[ianmcd]

have you tried replacing the batteries ? only use Duracell or equivalent dont use cheap ones they wont work

 

[robg172]

have you tried replacing the batteries ? only use Duracell or equivalent dont use cheap ones they wont work

Hi yes, however it seems more a problem with the receiver box that is connected to the mains plug. Only switching this on and off temporarily cures the heating problem.

 

[robg172]

Doing a bit of further research it seems the capacitor fails in the Digisat SCR, which initially is cured by powercycling however will eventually fail. Solution is new SCR or if you are a bit more technical replace the capacitor.

http://www.howtomendit.com/answers.php?id=49588

 

[Agile]

Yes, often replacing that capacitor will cure some of these types of fault on a Drayton Digistat or the British Gas rebadged version.

When the unit shows a green light but the relay is not energised to bring on the boiler then its usually that capacitor which has lost capacitance and does not provide enough voltage to operate the 24v relay. It is used to drop the mains 230v down to the 24v for the circuit and relay.

I keep those capacitors for repairing them in stock.

Tony