Thermecon s90/120 lockout fault

[Oddbod]

Hi,

I'm not a heating engineer and I have no intention of touching our boiler, but I really could do with some friendly advice regarding a weird fault.

The boiler is an 8-year old ThermeconS90/120. Burner is an Ecoflam Minor 4. Nozzle is a 1.10/60 Location is a dry outhouse.

When cold the boiler will fire with a flame established, but almost immediately locks out. Press the lockout button and the boiler fires and behaves normally. The fault only seems to occur when firing from cold. Any residual heat and things work fine.

What follows is the history. I'm not being critical of any of the engineers actions – the detail is just there 'cos I don't know what matters and what doesn’t.

The boiler was working perfectly until it was serviced. The nozzle was replaced however the port normally used for the air supply probe could not be used as something was “spinning around” (I assume the plug screw or connector thread stripped?). The engineer drilled a hole in the flue but then found he didn't have the right sensor equipment so didn't set up the air supply. There was no black smoke from the flue so it was deemed OK. He didn’t seal the hole in the flue.
Following the service there was a tiny continual oil leak from a connection - a drip an hour kind of thing.

After a week the fault started to occur and the engineer came back, cleaned the nozzle (it being sooted up) and set the combustion mixture using the hole in the flue for the sensor. It took a long time and the air setting ended up much higher than the manufacturers suggested range (and much higher from what it was when the boiler was working before the service)

It worked fine for a week and then the fault started to reoccur. The engineer stopped taking my calls.

I found a second engineer – really nice bloke, well recommended and clearly knew oil boilers.

The second engineer performed another service. Fixed the oil drip, cleaned out the baffles which were full of red powder and set up the combustion. Didn't change the nozzle.

A week later the fault reoccurred.

The engineer returned and replaced the nozzle. (On the grounds that the first one may have been faulty since it was the only thing replaced since the boiler had worked). Set up the combustion again, ending up with the air setting much nearer to the recommended value this time.

This morning the fault reoccured.

Before I ring him again I'm just wondering if anyone has any great ideas we could check out. This has all the makings of a “just throw bits at it 'till it works” saga. Which is fine if that's all we can do, but I'd feel daft if I hadn't at least asked if this problem rings a bell with someone.

Following are some additional points.They may or may not be correct.

The boiler was working fine until the service, so something happened at that point. The first engineer inadvertently damaged or changed something or otherwise provoked the fault – photocell, wire, control board? (I'm not having a pop here, I know that coincidence happens and that the slightest disturbance can exacerbate an existing fault. That said I do now wonder how experienced the first engineer actually was.)

According to the second engineer the photocell is clean and seems to be in the right place.

The oil tank is pretty full. It was not topped up, the supplier was not changed etc. The oil pressure and filter seem fine.

The solenoid seems to be OK (it seems they usually fail when hot not cold).

(See, I now know far more about oil boilers than I ever thought I would!)

So I have two questions. Is anyone thinking “Oh yeah, that's obviously.......”? Secondly would it be worth replacing the whole Ecoflam burner. I believe it's a couple of hundred pounds and, provided the fault is somewhere in the existing burner, it wouldn't take too many more visits for that to become the cheapest option – let alone the most convenient one!

Thanks for any advice.

Oddbod

 

[Oddbod]

Yep, James is still on the case! A new motor to be fitted and all sorts of oil unions to be tightened.

It's not yet 100% reliable and the auto reset device still kicks in from time to time, but it is soooo much better.

If we can get another year or two from it we'll ask James to fit something decent.

I'll post a picture of the other end of the reset device, with the electronics, tonight.

Thanks all

 

[Oddbod]

Here is photo of the other end


I had the bits lying around, but it would probably cost about £80 if I had to buy it all. It took about3 hours to make. The reset arm is a linear actuator from a lawnmower cutting deck height adjuster. It gets connected to 12v DC by the electronics. It moves forwards or backwards depending on the polarity.


The electronic gubbins is based on an Arduino micro controller. The black tube contains a neon indicator connected in parallel to the lock out light. (It’s 240v but very low current so not dangerous). The other end of the tube contains a5v light sensor that tells the micro controller if the lockout is on or off. The blue relays are connected as an H-bridge (basically a polarity flipper) and allow the micro controller to drive the actuator in either director. The little display just reports what the thing is up to – number of retrys, time before the next attempt etc etc. Finally the whole thing is driven by an old laptop power supply. The actuator needs about 1A at 12v.


When the software detects a lockout it waits 60 seconds and pushes the reset button. It tries this three times and then waits for an hour before trying another three times.It’ll do this forever if the reset light stays on. If it fails to start from cold three goes are usually enough. If it fails when hot an hour is usually enough to let it cool down to the point where it will restart.


I know it’s something Heath Robinson would be proud of, and I’m sure Thermecon would be having kittens if they knew about it, but until Bunker recommended James it was this or freeze!


Hopefully I’ll never have to make aMkII.


In the unlikely event that anyone is daft enough to want to know any more, ask away.

 

[lame plumber]

omg.................

 

[Oddbod]

You forgot the 'f'!

 

[Millsy 82]

Here is photo of the other end
View attachment 21231

I had the bits lying around, but it would probably cost about £80 if I had to buy it all. It took about3 hours to make. The reset arm is a linear actuator from a lawnmower cutting deck height adjuster. It gets connected to 12v DC by the electronics. It moves forwards or backwards depending on the polarity.


The electronic gubbins is based on an Arduino micro controller. The black tube contains a neon indicator connected in parallel to the lock out light. (It’s 240v but very low current so not dangerous). The other end of the tube contains a5v light sensor that tells the micro controller if the lockout is on or off. The blue relays are connected as an H-bridge (basically a polarity flipper) and allow the micro controller to drive the actuator in either director. The little display just reports what the thing is up to – number of retrys, time before the next attempt etc etc. Finally the whole thing is driven by an old laptop power supply. The actuator needs about 1A at 12v.


When the software detects a lockout it waits 60 seconds and pushes the reset button. It tries this three times and then waits for an hour before trying another three times.It’ll do this forever if the reset light stays on. If it fails to start from cold three goes are usually enough. If it fails when hot an hour is usually enough to let it cool down to the point where it will restart.


I know it’s something Heath Robinson would be proud of, and I’m sure Thermecon would be having kittens if they knew about it, but until Bunker recommended James it was this or freeze!


Hopefully I’ll never have to make aMkII.


In the unlikely event that anyone is daft enough to want to know any more, ask away.

Would it not of been better to spend the 3 hours finding and repairing the fault? I'm kind of guessing that is also at your home and not in someone's utility for them to trip over lol.

 

[oz-plumber]

I am intrigued...totally intrigued....as to why you called yourself...

'Oddbod'

As for the MK11 - Jaguar made one and it was very popular - probably their most recognized car.

As for asking more question being 'unlikely', I don't think it is a matter of us not being interested, its a matter of us not knowing what to ask.

You should take up lodgings, I'm sure you could be of assistance to many people on here.

Oz

 

[OilBoy]

Wow, what a great idea and know how. Respect

 

[Oddbod]

Millsy 82. Yep, it would have been infinitely better to spend 3 hours fixing the bleedin' thing. Unfortunately I'm just an ordinary punter, not a heating engineer.

Originally the idea was just to have the boiler serviced.

"I know", I thought, "I will use this new fangled interweb thing and find an engineer of repute and good standing. I will ply him with tea, biscuits and the odd florin from my hoard and I will be warm for another year."

The engineer duly arrived, drank my tea, ate my biscuits, took my florin and left me a boiler that locked out every couple of days. He came back couple of days later and repeated the process. Strangely he then stopped taking my calls.

"This is dashed unfortunate" thought I. "Let us find another engineer". So I did, and the story repeated.

In desperation I resolved to voyage - virtually - to the place where the soothsayers, shamans and gurus of boilers dwell - ukplumbersforum. There I will request audience and they shall advise me well.

And so they did. "'It's setup, over aired, its a thermecon, get a good engineer" they said.

And so I did, and so the story repeated.

By this time I was bloody cold, down £200 and 6 half days off work, had three engineers who wouldn't talk to me and was remembering Churchills maxim that stupidity is repeating the same thing and expecting a different outcome.

At this point a thought crossed my mind - not a long journey I confess. Why not build an auto-reset device and wait 'till the thing really does break. Surely then someone can fix it.

So since I used to design and build medical robotic instruments for a living thats what I did. It cost less than a 4th engineer, took less time and kept me going for a year.

(BTW if you are ever diagnosed by an "amerlite" machine ask for a second opinion - I helped design it).


OZ Plumber - When I was a spotty pubescent oik I decided that a mullet would turn me into a babe magnet. Unfortunately my sister decided it made me look more like oddbod from Carry on Screaming and it kinda stuck. In hindsight she was probably right. Me and my mullet did pull the odd babe, but probably more out of sympathy or morbid curiosity on their part.

Oilboy, thanks, but personally I admire you guys - and indeed all engineers of whatever ilk who keep odd bits of junk running year after year.

 

[Bunker]

Well its great to have a bit of colour in the forum, amazing work Oddball, a mate of mine is often tinkering with Arduinos - the sort of mate who often offers to 'draw me a diagram' (sharp exit stage left).
Thank God for you brainboxes, especially those with a sense of humour.

 

[Lou]

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