Magic Servant gas burner won’t light

1925storybook · September 3

last May I turned off the gas supply to our boiler because I was planning to give it a good cleaning during the summer. It is supposed to get cold this weekend so went to light the pilot and it will not stay lit. I assume this is a thermocouple problem as I had the same issue about 10 years ago. Fortunately I bought a spare at that time. This is the first time I’ve shut the pilot down in 8 or 9 years.
I thought I had a manual for this unit #359 but cannot seem to find it now. Any ideas to get one? I assume this is a gas conversion unit made in the 50’s or 60’s. Yes it’s old, as is the boiler, but works great. I just want to confirm I’m trying to relight it correctly. Thanks

Jamie Hall · September 3

Can you show a picture of the gas valve and pilot control? Some of them you need to hold a button down when trying to light the pilot — and hold it down for a time until the thermocouple heats up.

retiredguy · September 3

As @Jamie Hall wrote, send a few more pictures of the front of the burner and other controls. All this type burners had their own way to light the pilot and reset the safety shut off switch. I am not familiar with that burner name but most were similar. I do see a B50 GC gas valve but more pictures are necessary.

1925storybook · September 3

I think I’m doing it right. Turn on power, turn on gas supply. Make sure reset (bottom red button is in) press top red button and hold. Light pilot and wait for releasing. I’ve tried various times up to 90 seconds and shortly after releasing button pilot goes out. Do thermocouples tend to go bad if the pilot is extinguished after a long time in service? Thank you!

Jamie Hall · September 3

Thermocouples do go bad — but before condemning the thermocouple, make sure that the pilot flame is a good cheery flame, and that the thermocouple tip is well in the flame and getting good and hot — like glowing.

1925storybook · September 3

thanks, I’ll try again later today. I have to slide the whole assembly out to see the tip as it’s deep in there. If no success I’ll swap the thermocouple. I guess I learned my lesson, keep the pilot on!

retiredguy · September 3

To light that pilot, in case you don't know, you have to hold both red buttons down at the same time, the one on the right side of the gas valve and the one below that, and hold a lit match where it says "match hole". That "match hole" tubing is slotted at the bottom and acts as a pilot runner which should light the pilot. Here is where you need 3 hands; one for each button and one more to light the match. When the pilot lights, you can let go of the bottom red button and continue to hold the button on the gas valve for 1-3 minutes. If it won't stay lit, change the thermocouple first and try again. If the pilot still does not stay lit then you need that plug-in cntrol with the red button which you may not be able to buy. I know about these controls since I got into the trade when these were still a common control.If the pilot does not stay lit then you will need to call someone that knows what the replacement valve is.

mattmia2 · September 3

It could be replaced with a modern power burner by someone that knows what they are doing too depending on how lucky you feel about the rest of the boiler.

1925storybook · September 3

thank you, tried again and waited a long time to get the thermocouple really hot and it still won’t stay lit. i’ll drop in a new thermocouple tomorrow. I don’t mind changing the burner as I think the boiler may outlive me. When we bought the house 11years ago I planned to replace it but the Contractor I called out talked me out of it. It was a good call!

Steamhead · September 3

What make and model is the boiler?

1925storybook · September 4

so new thermocouple didn’t work. As soon as I let go of the upper button the pilot goes out. It would seem to me that the “match travel tube” valve should close at some stage which doesn’t seem to happen either. Guess it’s time to call in an expert. I’m guessing the reset box is not seeing feedback from the thermocouple to keep the pilot gas flowing. I believe this is an old US boiler, but it has no tags whatsoever. Do I simply need a new gas control valve?

1925storybook · September 4

upon doing a quick search online, these don’t seem to exist anymore… I suppose that’s not surprising, hence the comment above that a new burner may be needed.

mattmia2 · September 4

You'd have to replace it with a modern valve. The first thing to check is that the pilot flame is burning correctly so that it is heating the thermocouple, then the next step would be to check the output of the thermocouple with a voltmeter while holding the button in. It probably makes more sense to replace the burner than to retrofit a new valve to it if the thermocouple is good and it still isn't holding the safety valve open. Actually, is that safety valve attached to the main valve in some way or is it just on a bracket next to it? Versions of safety valves are available but I don't see how it keeps the main valve from opening if it isn't attached mechanically or electrically.

EdTheHeaterMan · September 4

You have 3 options, if the pilot reset control is in fact defective.

replace the boiler it is time. but as your original guy said, that boiler may actually outlast all of us.
Replace the burner with a newer burner that has modern replacement parts, that may come with a 1 year warranty
replace the gas valve only. it will have slightly different lighting instructions but will still use the lighting tube and need that additional pilot tube from the old manual pilot gas valve to get the flame to the actual pilot location.

However, using option #3… if you replace that gas valve only and you have the same problem, then what will you check next. That is where a pro can tell you that the pilot burner is dirty (the part that stays lit at the end of the lighting tube). If you try to clean that with compressed air to blow out the pilot orifice, then the pilot flame may actually get larger and the thermocouple will get hot enough to keep the safety switch engaged. on the old or a new gas valve.

Edit:

upon closer inspection of your photograph, it appears that the gas control valve and the pilot safety control have separated from each other.

My guess is that you need to replace the gas valve with a modern replacement or replace the entire burner.

1925storybook · September 4

Well, you’re all sort of right! Yes the separation is odd, and it’s been like that since we got here. In any case I took everything apart, blew out all the jets with compressed air, realigned the safety valve and tightened the internal contacts, made sure the thermocouple was positioned correctly, cleaned the clogged match pilot thingy (I think that’s a pilot runner?) and got the bottom reset button working smoothly (it was sticking in the pilot position). Lubed the blower motor, hooked up the gas, checked for leaks, and lit the pilot. Waited for 2 minutes like the plate says, released the button and the pilot stayed lit. Fired the main burner and made steam in 10 minutes.

Turned it off and back on and it fired right back up. I guess it’s good for another 50 years. It was quite filthy in there. Thank you all, I learned a lot, as usual!

mattmia2 · September 4

I'm still curious about how it shuts down the main valve, how is the pilot safely linked to the main valve, are there some electrical contacts we can't see?

1925storybook · September 4

yes, there are 4 pins on the safety switch 2 large and 2 small that mate with the main valve, only 2 wires connect to the recievers in the main valve and there is also a jumper between 2 contacts. How it all exactly works, I have no idea.

mattmia2 · September 4

I don't know what the jumper is, maybe it is for thermostat and safety chain connections in some applications but there is a switch in the safety valve that closes when the solenoid is held in by the thermocouple current and that is in series probably with the centrifugal switch on the motor that proves that the blower is turning and the 120v gas valve.

The thermostat and safety chain close a relay in the burner that turns on the motor then the centrifugal switch on the motor sends 120v to the gas valve.

Teh safety chain might be 120v and in the 120v connection to the burner too, judging from the flex it is probably on the 120v.

Steamhead · September 4

Looks like a standard thermocouple setup to me. The pilot valve also shuts off the gas to the main burner when it closes.

mattmia2 · September 4

https://forum.heatinghelp.com/discussion/comment/1809460#Comment_1809460

Trace the aluminum tubing around, the safety valve only goes to the pilot. It has an aux switch that inhibits the main valve.

Steamhead · September 4

OK, I see it now. But unlike the old A-B setups, this one is also 100% shutoff like a modern standing-pilot gas valve would be.

retiredguy · September 5

As I said in my comment, this valve set-up was common in 1960. They worked until they didn't. I never liked this set-up since I did not have a third hand to strike the match to light the pilot. I would look for an update so it doesn't leave you without heat on a cold winter's night when contractors charge double time or more. My 2 cents.

HVACNUT · September 5

I'm glad it worked out for you, and nobody needs to tape off the area and find the pieces. But I hope you were joking about "another 50 years." Even if you keep the boiler itself, a burner upgrade, new flue pipe with a good regulator and spill switch (stainless liner?) should be on your immediate "To Do" list IMO. And it's not DIY.

Being in service, the way I look at it is, what happens if the burner motor shorts out now? That looks like a tough find. Maybe you find it, but after 50 years, the fan is now fused to the shaft on the dead motor. And you wreck the fan trying to get it off. IDK why they call it "A can of worms", but that's what usually happens with old, neglected equipment. Those scorch marks going up out of the front plate and behind the LWCO is no longer an issue? All tight? Any draft numbers? Stay safe.

mattmia2 · September 5

https://forum.heatinghelp.com/discussion/comment/1809556#Comment_1809556

At very least someone that knows how to set up that burner should look at it which is a lot closer to the skills of a good oil burner tech than someone that works on modern atmospheric gas burners.

Magic Servant gas burner won’t light

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