Complex oil-burner ignition controller

Clive, if you're going to add a bit on at the end, perhaps you could devise a circuit using bipolar transistors or 4000 series gates that does exactly the same (at low voltage obviously). Or.. what about putting it out to your audience to see who can come up withe simplest (easiest to understand or fewest components) solution using only gates or transistors and conventional relays (but no microcontrollers) and offering the same functionality and error condition detection

Gordo

It may be a blocked orifice in the solenoid valve. The delay may be the hot case slowing the cooling down of the hot bimetallic strip. It won't reset until it has almost fully cooled.

Big Clive

Yep the oil solenoid, the main problem is they don’t seem to fail completely, they still do something but not enough. So you still hear a click from them but not enough power to activate the valve. Also I am interested to discover how the lockout seems to have a memory, so if you repeatedly press the reset the time seems to increase, I could not mechanically see how that works.

Graham Eida

Is it the fuel solenoids? Someone was mentioning that they commonly fail.

Big Clive

I have now had two solenoids go “weak” so hard to fault find as well as it still activates the valve, but just not enough!

Graham Eida

Ps yes the ending is a bit sudden; see what you mean

RDM

Fascinating really enjoyed this - the neons were so in keeping with the device. Similar one on my mother’s heating, (but with over temp cut out as well which activates the fault cut out) ah many years of fun cleaning the flame sensor and other repairs (motor cap / debris on the spark sensor the last two )

RDM

A detail draughtsman's nightmare...

Andrew Donaldson

Many oil burners in the States don't even have oil solenoids.

You're showing your age Steve.

I like this video very much. Amazing to see how inventive they were with electro mechanics way before computers of even electronic circuits became a thing. Everything is done using physical timing, pieces moving and basically doing four different things in one move. Very very clever!

Frank

Every time

Michael Thompson

This solves the mystery of why we had to hold the button in so long to reset our previous oil burner. We thought it was to discharge a capacitor, but never guessed it being waiting for a metallic strip to cool. I reckon my uncle's oil fired range (kitchen unit with an oven and hotplates) uses the second oil pump. After it fires up, it makes a distinct change in sound after about 30 seconds.

Seán Byrne

When Clive puts "complex" in the title you know you're in for a treat.

MrTridac

So complex

I positioned them out of the way of where stuff is happening, but will remove them as they are intrusive.

Big Clive

Earlly oil burners were nothing more than an asbestos wick sat in a plate, we had 2 of them, they had to be on the same level as the mechanical contol unit that worked by a float and a flow speed control with no electronics involved. The wick soon carboned up, the anual service was to remove the solid lump of carbon that used to be the wick, scrape the whole burner clean and fit a new asbestos wick. If for any reason the burner went out between services then the only way to re light it was with a blow lamp, heating the whole unit until the oil vapourised and it lit ! The after service lighting method was simpley turn on the oil for 15 mins and then light it with a match, the oil in the wick would then bairly ignite and slowly work it's way down untill the whole thing got hot enough for the oil to vaporise.

A well filmed narrated and explained video Clive.. That is an amazingly satisfying mechanical analog device. Which is obviously reliable as it has been used for years. No doubt there are also now digital versions where everything is controlled in software, via relays. Presumably something similar is used for gas burners.

Dr Andy Hill

Hi Clive, thanks for another great video. One thing: the last 20 seconds of the video are slightly hidden/covered by Youtube's buttons for next-to-watch video, and a link to you channel. Perhaps a lead out of 20 seconds would help here?

Paul Schuur

My first suspicion would have been a dirty flame sensor on the edge of operation. For the solenoid it could have been a fatigued wire connection inside which would gradually break contact as it warmed up.

Big Clive

The old washing machine programmers were quite interesting. Nice noises as they operated too.

Big Clive

In that era there were probably electromechanical designers who specialised in complex integrated mechanisms like this.

Big Clive

That is amazing, the only other time I have seen anything so complex was the control switch on the Hotpoint Twin tub washing machine I had when I first got married- I had to repair it twice and it was a minefield of levers and contacts over 6 layers, all on a rotary switch. It took me 2 days to reassemble it the first time it decided to demolish itself.

Mike Hughes

That is Murphy's Law for you!!

Mike Hughes

ABSOLUTELY BRILLIANT! So THAT is what's going on inside that box! I have an identical unit on my boiler and one freezing cold weekend recently (it would have to be freezing cold and a weekend) the boiler kept on tripping out. Little orange light behind the push button, push, reset and then it would run for 10 minutes and trip again! We struggled by (hot water OK with immersion heater, and electric heaters moved into key rooms) until my Heating Engineer visited on the Monday and proceeded to solve the problem in 10 minutes! He knew what it was as it's apparently now a "common" fault developing on boilers of a certain age. It was caused by the Danfoss solenoid coil on the fuel pump inlet dropping out because it's "ageing"? When the boiler was cold the solenoid would hold the oil valve open for 15 minutes and then trip but once the boiler was hot it only lasted 7 - 10 minutes. My friendly engineer couldn't explain exactly what causes "ageing" of a solenoid so over to you Clive! what on earth causes a solenoid to fail like this? Oxidation in the windings ? or .........?. Anyway thanks again, it is deeply satisfying to see such complex switching being achieved with old electro mechanical tech! Especially when I own one! Great explanation and video. Yes it did have a bit of an abrupt ending, but no big issue. (And you could also have used your coloured pens again to make that flame in your diagram look spectacular! ha ha)

Biggest problem is when you ask "How many times did you push the reset? "Just Twice" then you fix it, it ignites, the house shakes as all that oil boils in the bottom of the combustion chamber, or the bricks (soaked) in oil combust for an hour, all the soot in the chimney is on fire, and that's red hot, or melting. Now they say, "Well we all pushed it twice, for a few days, why is it a problem" But now I'm on the phone with the fire department.

It's amazing they get so much function out of so little hardware. I can't imagine anyone designing that from scratch. I can only see the design being incrementally modified over decades.

Nani Isobel

Something about a bunch of old neons hanging on a few resistors...that takes me back... The fact that you understand it and have the willingness to show them in operation is so the worth for the ticket in. I love it when the subject says to you , "slow down. stop. pay attentin this is happening at ITS pace"

Michael Thompson

Cool I wanted to see this!

Michael Thompson

I believe it burns oil in some capacity

Michael Thompson

What's an oil burner used for?

Bas

Never having actually had to remove one of these modules before, I didn't realise it was so small with a big junction box underneath. I thought it filled that entire box. It's an extremely compact and simple sequencing solution, but I'd choose to do it with relays and circuitry if I was designing one from scratch. Maybe having two independent circuit modules monitoring the flame sensor as a safety feature.

Big Clive

Great breakdown of these controllers, I work with a similar style for waste oil burners. Mine are branded Siemens but I am sure are all Chinese Clones, I have a couple that are a similar mechanical mess of contacts, but most of mine are an electronic design, using relays and a couple of small chips. They do the exact same sequence, but I've found the electronic controllers to be more reliable for my application

Themoolife

The next thing you need to show us is the artificial intelligence portion of the furnace that detects the worst time to fail. Somehow they always know to fail on a long weekend during the coldest time of year when you are not home.

Lostngone

I'll try to remember to add a pause.

Big Clive

Would it be possible to add a few seconds of opening title at start of each video? It takes a second or so for audio to start on all my devices (digital audio perhaps), and I miss first words sometimes.

Jim Hooke