I'm pretty sure the item in MM's link in his later post is the lockout which lives outside with the oily bits, the overheat "trip" is on the "inside the house" side (and I have turned the wick down slightly on my boiler stat which has resulted in it's not tripping this any longer (not that it did it more than a couple of times in 5 or so years anyway)).
The DK0970 manual is at
Most such controllers use relays to drive external bits so if there really is absolute silence (not even a very faint click - you might have to listen with a screwdriver to your ear and on the box) then the controller isn't telling anything to do anything and lockout will occur a short time later.
The voltage on the controller terminals 3 to 7 should give you a clue as to what is going on. The LED should also flash during startup to indicate what is going on - does it (for a successful start)?
Nope. During and after a successful start the LED does NOT light.
This afternoon, continuing my test 15-minute periods (see previous post in thread) since this morning, it came on twice successfully and three times needed reset (LED on).
MM
I don't snip where the context is important to trace.
MM
The purpose of the capacitor is to enable the motor to start. Ther eis a slight chance it is faulty but not great. The fault seems to arise in the motor not running. If the motor doesn't run,the boiler will go to lockout. Either there is no power to the motor or the motor (or capacitor) is faulty.
So, Is the motor free to revolve? Is electricity getting to the motor? Are both the start and run windings non open circuit?
There is a series of events/tests on start up. An event cannot start until the preceding event is complete/ tested positve.
it:
manual:
When my boiler locks out, there is no indication whatsoever of any prior activity. The Danfoss "calls for heat", some seconds elapse, the LED comes on. Finito.
MM
Does the lockout LED come on at the same time as the power indicator or does the power indicator lead by some seconds?
Bullshite.
Ah, now that I cannot say! It is something that has been bugging me, too.
You see, the Danfoss is inside the house and the boiler is outside on the garage wall. I cannot observe both switching on the manyal override button on the Danfoss whilst simultaneously watching the boiler control box LED.
Even if I let the heating come on by a timed event and am waiting outside the boiler a minute or two earlier, I cannot watch both the LED on the Danfoss AND the LED on the control box!
I even thought of setting up my web cam, but that would entail major upheaval throughout the house. Not saying I wouldn't do it, though...
I actually thought of mirrors. When my previous car was due its MOT I checked the stop lights by means of a mirror mounted temporarily on my standard lamp!
If you have any ideas how this may be achieved, feel free to suggest anything!
Now I'll try and draw you a picture of the layout:
The toilet has an opening window near the boiler. Sometimes, in order to check whether the boiler has come on, I open the toilet window and listen for (a) the fan and (b) the burner.
But I can't see any way to press the button on the Danfoss AND watch the control box. I can't ask the neighbour to press the Danfoss button for me while I watch the boiler because he's waiting for a heart valve replacement, is quite poorly and never goes out in the cold weather which apparently hits him like a train. And if I allow the Danfoss to trigger on the timer, then I cannot see the exact second it actually sends its "call for heat" message to the boiler.
I need some ingenious method like my mirror on a stick for checking the stop lights!
MM
Snip, you bastard.
Here's a thought..........
What if th lockout is occurring not as part of the startup procedure, but at the end Of the previous shutdown?
This COULD POSSIBLY be caused by flue gasses or unspent oil hanging Around (due to them not having been got rid of by the fan "running on" After the firing (because it has no mains as (I think) there is no perms ant live.
As I stated earlier IANAHE and I don't know if it could work this way, but it might.
That's good. I don't read messages if it looks like I'm going to have to scroll through the complete works of shakespeare just to get to some new content :-)
layout:
I don't know enough about boilers to be able to tell, although your point sounds perfectly reasonable. But the thing is, the moment that the Danfoss switches off, so does the boiler, including the control box LED. I know this because several times I've checked the boiler BEFORE switching on the Danfoss (or allowing it to trigger by timer) and the control box LED is always off to begin with.
Here may be one new clue: For the past few weeks I have programmed the "call for heat" cycles as follows (on the Danfoss):
Mon through Sun, heating only (I switch on the boiler for hot water only when needed, not on the timer): ON at 04:30 OFF at 05:00 ON at 17:00 OFF at 17:00 (i.e. NO call for heat, see note below) ON at 23:00 OFF at 23:30
This was purely for frost protection purposes so that it didn't get too cold in the loft (I've since opened the loft hatch by 45 degrees as well).
However, since the weather turned colder, I've revised the programme as follows: ON at 04:30 OFF at 07:30 ON at 16:00 OFF at 17:30 ON at 21:00 OFF at 22:30
Note on the Danfoss: If the ON and OFF times are the same, this effectively cancels that event.
Now, since I went to the longer ON times I've noticed that the boiler also locks out sometimes during the cycle. So, for instance, it will come on at 04:30, rads get nice and hot, then I happen to be passing one of the rads and feel it and it's going cold again. This has happened at random times. On checking the control box LED, it's ON constant, ie. locked out. I press the reset button once more and the boiler comes on and usually finishes its cycle, e.g. right up until
07:30.On one occasion the lockout happened after about 30 minutes into the cycle. Another time the boiler ran for about 1.5 hours and then lockout occurred.
Usually, however, once the boiler has started, it will run to the end of the desired period.
When I say "run", I mean that its typical behaviour is to come on, burn for about 15 minutes, then switch off. It then waits for around 4 minutes and then comes back on for only a few minutes, provided the cycle specified by the Danfoss programme is still active. The boiler will thus switch itself ON and OFF numerous times during a long "call for heat" cycle.
If any part of the above isn't clear, let me know!
Thanks for your response BTW.
MM
I was wondering if it might be wise to place a small mains bulb across the pump motor, to indicate when the motor has power but doesn't actually run.
And/or across the mains L and N in to see if the thing comes on in the lockout state, easier than mirrors. B-)
The bulb holder and flex from a pendant light fitting with a 15W pygmy bulb fitted would do, so would a 60W GLS but would be a bit bright next to a LED. Obviously want a light that comes on straight away...
Did MM's boiler man change the motor capacitor yesterday? If so has it made any difference?
Hide quoted text -
Oil pump? Or water pump?
Well it'll be the fan motor that also drives the oil pump.
Forgot to say that a neon screwdriver would also serve as mains on indicator to save faffing about with bulbs etc...
Hmmm....
As I said, I am no expert either, but I begin to suspect either the Danfoss, or else the moterised valvery gubbins. Maybe as an earlier poster suggested they aren't switching cleanly.
But the intermittant nateure of the problem is an embuggerating factor.
Could you wire up a plug in (or some other form) of timer as a temporary supply to the boiler and pump and switch it on and off a number of times and see whether you do or don't get lockout? If it locksout, then it's probably not Danfoss/Valve(s) if it does, then... well, you're probably no further on.
Chris
Do let us (and future generations) know what it was when you've solved it.
He didn't come yet...
Yeah, I know! :(
MM
I really will do that, certainly.
As for the most recent suggestions about a neon screwdriver or a bulb, I really wouldn't know what I'm doing there, I'm afraid. I can change a plug, even add a 13amp spur (though no longer legally permissible as a DIY job), but playing around with either the Danfoss wiring or the boiler wiring is simply beyond me, sorry.
MM
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