Honeywell / Satronic control box DKO 970 for Wallstar 15/20

[MM]

This is the oil burner safety control (model DKO 970) on my Wallstar
15/20 boiler, which once again is playing up.

I downloaded the 6-page manual http://tinyurl.com/bz56n77 for the
DKO 970 and studied the flash codes.

In the manual on page 2 in the paragraph "1.2 Lock-out diagnoses" it
says the following:

In case of a failure the LED is permanently illuminated. Every
10 seconds the illumination is interrupted by a flash code,
which indicates the cause of the error. Therefore the following
sequence is performed which is repeated as long as the unit
is not reset.

Sequence:

illuminated phase dark phase Flash-Code dark phase
x z z z z

[where illuminated phase = 10 sec, dark phase = 0.6 sec, second dark
phase = 1.2 sec -- I can't fit all that on one line in FreeAgent
like in the actual PDF]

Error diagnosis
Error message: lockout
Flash-Code: x z z z z
Possible fault: within lock out safety time
no flame establishment

[where x = short pulse, z = long pulse]

This is the sequence I observe on my boiler when it won't start.

So my question is:

What does "within lock out safety time no flame establishment" mean in
layman's language?

Does this point to the burner, the igniter, the solenoid, or another
component?

NB: The boiler ALWAYS starts when I press the reset button on the DKO
970. I never have to press it more than once. The boiler then runs
perfectly, cycling through on/off phases exactly as it should.

But next morning it won't start and the above flash code sequence can
be observed. There's plenty of oil in the tank.

Thanks.

MM

[Allan Mac]

On 11 Nov, 08:15, MM <kylix...@yahoo.co.uk> wrote:
> This is the oil burner safety control (model DKO 970) on my Wallstar
> 15/20 boiler, which once again is playing up.
>

> I downloaded the 6-page manualhttp://tinyurl.com/bz56n77for the

If the photocell doesn't see a flame within a preset period the
ignition process stops. This prevents oil being squirted into the
burner, and a potential explotion. There are a few possible causes

Dirty photocell
No ignition spark
Oil valve not opening
Faulty control box
clogged nozzle
Faulty oil pump

Diagnosis of this kind of fault can be difficult.

Good luck. Allan

[Allan Mac]

Just remembered, saw this once before where the plastic drive coupling
to the oil pump had worn

[MM]

Thanks for that useful advice, Allan. I'll pass it on to my heating
engineer. He's a bit flummoxed over my boiler, but has a good
reputation. On Wednesday he fitted a new transformer.

Unlikely to be the pump, as he fitted a new one two years ago. When I
told him the reset switch was still having to be pressed, he asked me
to note down the control's model number, so I assume he's sourcing a
new one or maybe himself researching the flash codes (which I had told
him).

Not a problem all the while I'm here, but when I go away and there's a
sudden cold snap, that's when the boiler needs to be utterly reliable
otherwise the house goes cold and there's then the risk of frozen
pipes.

My gas boiler down in High Wycombe seemed simple in comparison with
this Wallstar! It was maintained each year by Servowarm, who only
needed to fit a new thermocouple every few years. That gas boiler was
23 years old by the time I moved out.

>
>Diagnosis of this kind of fault can be difficult.

You're telling me! Heating engineer said he had one stubborn case
(different make of oil boiler though) that he was working on for
several days.

>
>Good luck. Allan

Cheers!

MM

[ARW]

Have you considered using an engineer that knows what they are doing?

--
Adam

[MM]

No, of course not! Are you mad, sir?

MM