old style transformer question

Barksdale

In your experience can a transformer like the FRANCE 5LAY-04 fail intermittently where there's no spark one minute then pulls a healthy spark the next? Do they all just get weak or fail completely? Thanks.

STEVEusaPA

Yes, to all your questions. lol
First I'd double check the wiring, then I would bench test it for spark, then ohm out primary leads, and each lead to ground.
But you didn't provide enough of the story. You could have spark but no flame due to a multitude of things-Problem with fuel pump, loss of prime, dirty end cone, cracked/worn/dirty/misaligned electrodes, plugged or partially plugged nozzle, and on and on.

Here's some checkout procedures for transformers:
Electronic:
Beckett Ignitors <2000 ohms each post to ground, no more than 10% difference between post measurements.
Carlin Ignitors
1. Test for spark, should jump 3/4"
2. Secondary coil test. Each post to ground. They don't give a number but the difference between each electrode to ground should be less than 10%.
3. Input current test.
a. Put the clips about 1/2" apart.
b. Multimeter wired in series set to read milliamps AC (yes milli, not micro).
c. Power up with test cord and run for 5 minutes.
d. If reading drops below 300 milliamps at any time, replace ignitor.
Carlins will fail the milliamp test only most of the times, so always do 'd' if you have a Carlin ignitor that you suspect is the problem.

Iron Core Transformer- Check spark as noted above. Remove wiring check ohms on primary leads, then check each post to ground:
.....Primary Leads........Each Post to Ground
Alanson- 2.4 ohms............9200 ohms
France- 3.0 ohms.............12000 ohms
Webster- 3.8 ohms...........10800 ohms
Dongan- 3.0 ohms............12000 ohms

Edit: for those playing along at home. All ohms tests are done with no power to transformer.

EdTheHeaterMan

Sounds like a lot of testing for a low-cost item. Steve. I have been stymied by the illusive Ignition failure many times. Sometimes you just need to be there and listen for the "by chance." "one in 100," beguiling, intermittent failure of the oil burner ignition device. Sometimes you just change it out for the hell of it because it is the lowest price part of all the possibilities.

I do like to "KNOW FOR SURE" that a part is defective before replacing it. Ohming motor windings and power valves directly (bypassing all the limits) to determine if the part is actually bad. I even have one of the recalled Diversetik multi capacitors (the one with the switches on the bottom) to use as a diagnostic tool to check out motors and compressors with unreadable labels. But the oil ignition is my one exception over the years. I never purchased any of the "ignition Testers" over the 40+ years of oil burner work. Some may say that is not very professional, but I could not see the value of placing two meters in every service van for such an inexpensive part. It if was under a service agreement that covered parts, It was a no-brainer. "if there is a possibility it's the problem, Just change it out." If it was a paying customer, I would offer to put the old one back if it did not resolve the problem and give full credit. (i remember doing that once or twice)

I was extremely elated with the advent of the Diagnostic Primary Controls. I even had a price for installing the primary to log the failure when I was not there... and a separate (lower) price for refunding the consumer for putting back their old 3 wire control once the problem was discovered. The difference was the "rental" or usage fee for the control. I rarely needed to use it but some consumers just can't afford to keep a part that was not absolutely necessary. Most customers did keep the control,l because of the extra features... and the display screen was kind of cool.

Yours Truly,
Mr.Ed

STEVEusaPA

Doesn't sound like a lot of testing at all. Check the leads, check each post to ground, check post to post.
Takes the same amount of time to type it than it does to do it.

EdTheHeaterMan

Agree, Steve. but specialty testing meters for both types is what I feel is worthless.

JUGHNE

Has anyone used the "Dongan 10,000 volt meter"?
I picked it up at an auction many years ago.
It is simply an iron core transformer with leads/clips that connect the output of transformer to be tested to the secondary of the test meter transformer, meter is connected to primary and scaled to read 10,000 volts in center scale.
(feeding testing meter backwards)
Carrying handle and plug in leads included.

Could this be left connected for 5-10 minutes to see if the transformer was breaking down (decay of output)?

STEVEusaPA

EdTheHeaterMan said:

Agree, Steve. but specialty testing meters for both types is what I feel is worthless.

I only use a DMM.

JUGHNE said:

Has anyone used the "Dongan 10,000 volt meter"?
I picked it up at an auction many years ago.
It is simply an iron core transformer with leads/clips that connect the output of transformer to be tested to the secondary of the test meter transformer, meter is connected to primary and scaled to read 10,000 volts in center scale.
(feeding testing meter backwards)
Carrying handle and plug in leads included.

Could this be left connected for 5-10 minutes to see if the transformer was breaking down (decay of output)?

My Dad had one, I never used it (might still be in the shop). That would be easier than 'putting it under the gun', so to speak where you take the transformer to the bench, stick the nozzle assembly on it, and let it run with a test cord.
Can't speak to whether it works.
For old style, check spark, then check like I mentioned before (leads, post to post, post to ground). I've never had one pass those tests and still be the cause of a nuisance lock out. And if it failed those simple tests, I replaced it.

Now a Beckett electronic, different story.
Carlin electronic, had a bad run of them about 5 years ago where the only test it failed was the 'input current test'.
I've been putting the old style back on. Yes they are heavy, but I've never seen in 30+ years where I replaced a second iron core transformer on any piece of equipment, especially on interrupted ignition.

Barksdale

I'm getting different readings from the 12kohms posted above. My FRANCE 5LAY-04 reads 3.1 ohms between posts and from post to ground 35.6 kohm and 32.9 kohms. It pulls a spark an inch but if I start it with a screwdriver gap of 3/16" to 1/4" it will fail to jump every few tries.

STEVEusaPA

If your wires/wire nuts are good, and intermittent spark, it's bad. Out of range-high ohms, it's bad.
I think you meant 3.1 ohms on the two wire leads.

Barksdale

Right. 3.1 on the wire leads. Thanks. I'm going to replace it.

STEVEusaPA said:

If your wires/wire nuts are good, and intermittent spark, it's bad. Out of range-high ohms, it's bad.
I think you meant 3.1 ohms on the two wire leads.

HVACNUT

Now are you going to install another ignition transformer, or a 14k volt igniter? Is the primary interrupted ignition?

Steamhead

HVACNUT said:

Now are you going to install another ignition transformer, or a 14k volt igniter? Is the primary interrupted ignition?

Very important. The old 3-wire primaries (Honeywell R8184 or similar) don't shut off the ignition while the burner is running, which will shorten the life of the ignitor and electrodes, and many of them take way too long- 45 seconds or so- to stop the burner if it doesn't light. For some reason these things are still sold, though I've heard some local Codes no longer approve them.

Do yourself a favor- if you have one of these 3-wire primaries, upgrade to a 15-second model that will shut off the ignition after the burner starts successfully ("interrupted ignition").

EBEBRATT-Ed

We used to have in the old days a "hot stick" I can't remember who made them but they worked.

If you were testing a 10K transformer you put the lead on a good ground and put the tip of the hot stick on the transformer pole had a small knob you turned line thet up with the 5k mark. If the light lit you were good if not bad.

Don't know why they stopped making them

STEVEusaPA

EBEBRATT-Ed said:

We used to have in the old days a "hot stick" I can't remember who made them but they worked.

If you were testing a 10K transformer you put the lead on a good ground and put the tip of the hot stick on the transformer pole had a small knob you turned line thet up with the 5k mark. If the light lit you were good if not bad.

Don't know why they stopped making them

That sounds interesting. Never saw that.

mattmia2

You can get high voltage probes, both with an integral meter or as a voltage multiplier with a connection for your own meter. You could also make the specialty device described above by hooking the secondary and ground of 2 transformers together, powering one, and looking at the primary voltage of the other with a meter or even a light bulb.

STEVEusaPA

mattmia2 said:

You can get high voltage probes, both with an integral meter or as a voltage multiplier with a connection for your own meter. You could also make the specialty device described above by hooking the secondary and ground of 2 transformers together, powering one, and looking at the primary voltage of the other with a meter or even a light bulb.

Or you could just do it the way I posted and not over complicate it.

SuperTech

I honestly think the most important thing with oil is to convert to interrupted ignition whenever possible. I rarely see ignition issues, regardless of igniter or transformer,  when the customer has interrupted ignition. Two or three seconds versus several minutes of runtime make a big difference on the lifespan of igniter/transformer and the electrodes. 

Barksdale

A quick update confirming it was a failing transformer. That one was good for 20 years so went with an Allanson. No more random delayed starts or lockouts. Fires immediately. I already replaced the original 45 second primary a few weeks ago after a delayed ignition blew the damper and breaching off. Sure got my attention. Even with the 15 second model I got a loud boom on delay. A 5-10 would be even better.

Thanks for all the replies and a great forum.

EBEBRATT-Ed

Face it, like everything else transformers and ignitors are not made half a good as they used to be.

I have pulled out a lot of old burners that had run 30-40 years and were still running with the original transformer. You new they were original because they were painted the same color as the burner.

Constant ignition or not they lasted. That was a common question when I went to burner school 50 years ago "will constant ignition burn out a transformer" The answer was no.

But those old transformers you didn't pick them up with one hand, they were heavy.

Probably had more copper and nasty PCbs in them

But times have changed, the new ones don't last, interrupted ignition is better and shorter lockout times are better

I have worked on old burners where they wouldn't stay lit without constant ignition

And constant ignition was considered safer back then. The motor was wired parallel with the transformer so if the burner was throwing oil you had a spark. You didn't have to worry about a bad ignition relay in the old stack switch