On Sun, 2 Dec 2012 23:14:19 -0800 (PST), harry
wrote:

On Dec 3, 6:38*am, MM wrote:
Sorry to have to bore you chaps yet again with my woes. The boiler is,
as ever, unreliable at starting, frequently going into lockout when
the Danfoss timer calls for heating.

Yesterday evening the heating was due to come on at 20:00 so I went
out at 19:57, took off the boiler cover and watched the DKO 970
control box closely.

At precisely 20:00 the LED came on and stayed on. No flash code.

There was NO OTHER activity inside the boiler. No sound of the pump,
no movement of oil in the supply pipe, no sound of any spark, no
clicks, no nothing. The ONLY thing that happened was that the LED came
on.

I pressed the reset button and the boiler started.

However, now I am noticing that the boiler is locking out DURING the
cycle. This morning at 04:30 am it started okay. The Danfoss timer is
timed to come on at 04:30 and go off at 07:30.

But at around 04:50 (yes, I'm not getting much sleep!) I noticed that
the rads were going cold again, so I went out and checked and, yes,
the LED was ON constant. I pressed the Reset button and it started
again.

But just now, at around 06:00 am, the same thing happened. Rads going
cold, boiler locked out, LED ON. I've just pressed the Reset button
for a second time.

Is perhaps the temperature set too high? What about the knob on the
white boiler housing inside the garage? It's turned to MAX.

By the way, the current heating session is for HEATING only.

As a way of explanation, can anyone please clarify the typical
start-up process of an oil boiler for me?

I assume that the flame is ignited by means of electrodes, similar to
a spark plug?

So I further assume that the electrodes are set to start sparking
BEFORE any oil is sprayed into the combustion chamber?

I further assume that if the control box detects no flame AFTER this
initial sequence, it goes into lockout mode?

Is this how it proceeds? Please excuse my lack of knowledge. I am a
motor fitter by trade, not a heating engineer!

Many thanks to all who respond. I'm at my wits end with this Wallstar.

MM

I assume you are talking about a pressure jet oil burner

I don't know what type it is. It is a Wallstar 15/20 oil boiler. It
has a pump that sucks oil from the tank in the garden. It is
approximately eight years old. This is the handbook that came with it:
http://www.wallstar.co.uk/content/pdfs/wallstar.pdf


Normally when a boiler locks out, a red light comes on. Is this the
case with you?

Yes.

A boiler locks out on startup when for some reason the flame fails to
establish or if the flame detecting device fails to see the flame.
So the cause can be

No/insufficient oil.

There is plenty in the tank.

Polluted oil (water).

Engineer used dipstick smeared with special gunge that changes colour
if water is present. There is no water.

Low oil/air pressure/faulty pressure switch for measuring them.
Worn jet, oil not atomising, hard to ignite.
No spark-Faulty transformer, (dirty)sparkplug
Faulty sequence controller.

Engineer has checked the above exhaustively over the past month and
cleaned whatever components needed cleaning. New transformer, control
box, solenoid and photocell fitted in the last two weeks. The pump was
replaced in 2010 because it was diagnosed "noisy".

Flame failure device doesn't "see the flame"- faulty/dirty.

New photocell fitted (see above).

Start up sequence is
Purge (fan runs for 10-15 seconds, clears any fuel vapours present)

No fan can be heard to start. There is NO noise of ANY kind when the
LED comes on. I have had the boiler cover off and stood in front of it
listening intently for any signs of life. Zilch.

Pressure tested (fuel and air)
Spark

Would one hear that sparking?

Fuel valve(s) open

Ditto?

Flame is established
Flame sensor sees flame.

These would give SOME indication of activity on observation, would
they not?

On shut down
Fuel is cut off
Post purge (fan clears combustion gases)

If these things don't happen/fail for any reason you get a lockout.
You need to establish at what point lockout occurs. This gives a clue
as to what is faulty.

That's the problem. There IS no clue! The LED comes on and stays on.
There is no flash (diagnostics) code on the LED. The control box is a
DKO970. This is the manual:
http://www.ifs-store.com/pdf/satroni...%20-%20972.pdf

And yet the Reset button ALWAYS starts the boiler immediately! In
fact, that is when I *DO* hear the fan going, whereupon the burner
fires up a few seconds later.

When the LED first lights up, it's as if the sequence you describe
isn't even starting at all -- as if there is an "OK" box waiting for
a click in Windows to acknowledge something!

Like I said, it's a total mystery, both to me and the heating
engineer, and I have it on good authority from other residents that
this chap knows what he's doing.

A previous correspondent in this ng stated a few weeks ago that this
kind of intermittent problem can be damned difficult to fix sometimes.

Thanks for your response!

MM