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Lincoln 1046 Heating but not Cooking
Hi All, this is my first time here as I just joined up.
My background is as an electrician, then a Xerox centralised printer tech, then I got into cutting and programming auto keys.
The reason for my post is I also buy and sell electrical equipment and I had a guy by the name of Ami come around to look at a Pizza Oven I have for sale but as it turned out, it wasn’t what he was after as it was a countertop model and too small for his needs.
Ami owns a pizza shop and he was after another machine because his Lincoln 1046 had stopped working after he had a technician come out to look at it due to an intermittent problem where it would stop heating.
The tech that came out spent around two hours there with an apprentice watching on and eventually finished and tested the oven (which was working when he arrived, by the way) and a pizza went through and cooked okay.
However, his diagnosis was that the machine needed a pressure switch and an ignition pack.
He then charged Ami for 5 hours labour to diagnose the problem.
When Ami asked why it was 5 hours, the tech (who is also the owner of the repair business) told him it was two and a half hours for him and the same for his apprentice (who had for the entire time just stood and watched her employer) and he charged Ami $550 for the diagnosis.
Ami needed the machine to be working so he paid the full amount immediately and asked the tech to get the parts and bring them back asap.
The tech did not return.
I know all this because Ami showed me the back and forth text messages where the tech basically said he wouldn’t be coming back because he couldn’t be sure that he would get paid even though Ami had paid him immediately for this visit and paid him on previous occasions when Ami had him out to do services on his oven.
However, after the tech left, Ami ran one more pizza through and then the oven stopped working completely and he couldn’t get it going again.
Ami contacted the tech and asked him to return asap with the parts that were quoted at over $1000 for the two items and get the oven working as otherwise he would have to close his shop.
Anyway, Ami came to see my oven when his shop had been closed for five days due to the tech not returning and then refusing to return calls and text messages.
I was stupefied that a tech would do such a thing to a fellow small business owner and left Ami in the lurch whereby he had to close his shop and throw away a heap of fresh stock.
I told Ami that even though I wasn’t a pizza oven tech, I am an electrician and I would go to his shop and have a look at the oven and see if I could do anything to get his oven going so he could open his shop again.
I downloaded the service manual for the Lincoln 1046 and had a read and also found the tech town forum which was also informative.
When I got to the shop yesterday afternoon, I took the top off the control box and found a schematic stuck to the underside of the lid.
It appears that the oven was originally an electric oven that had been converted to gas from what I could gather, as the 1046 manual schematic compared to the schematic attached to the lid which shows it as a Series 1000 model 1028 or 1029 electric oven whereas the front plate lists it as a 1046 gas oven.
Anyway, the first thing I found after turning the machine on was the conveyor wasn’t moving so I checked the fuses on the front of the control panel and found one of the 3A fuses was blown.
I sent Ami off to buy some fuses and while he was gone I had a look at the various components to try and understand how it all worked and what the various parts were.
During this inspection, I found the speed control board had two fuses on it and the top 4A fuse looked unusual so I removed it and found the fuse had previously blown and someone had actually coiled some fine wire around the outside of the fuse shell and placed it back in it’s holder. I have no idea how long it’s been like that but the tech should have found that and replaced it in his two hour diagnosis.
When Ami returned, I replaced that fuse and the blown 3A fuse and turned the oven on and found the conveyor now worked and the contactor now clicked in but the gas didn’t fire up and the oven wouldn’t heat.
I then found two units that had adjustment screws so I turned the central green screw on the Honeywell one first as I thought that was the air pressure switch. I had read that to adjust the switch, the screw has to be turned counterclockwise until it stops and then turned in till it ignites and then back it off a 1/4 turn.
However, when I turned this centre screw outwards, it kept going until it was all the way out and there was a spring under it so I turned it back in until it just activated the three terminal micro switch on the back of the unit.
Doing all this didn’t get the heater working so I then pulled the cover off the Johnson Controls box next to the Honeywell and found a three terminal switch with an adjustment screw above it. I turned this screw out until it stopped and then in as the adjustment said and when I turned the oven on, the heater started and the gas ignited.
I then had another problem though because the InkBird PID was set at 230c but fluctuating between 215c and going up to 255c.
Ami told me it usually stayed around the 230c mark and didn’t stray wildly like it was doing now.
We ran a pizza through but it wasn’t cooked so had a look in the side door and felt a lot of heat come out.
I put a small paper bag in there on top of the conveyer as I expected it to get blown around with the forced air but there was nothing. It just sat there motionless.
I’m now at the point where I believe the heating side is working but the heated forced air isn’t and so the temperature is not hot enough or consistent enough to cook the pizzas.
My question now is, where is the blower fan that forces the hot air throughout the machine located and is it affected by the Johnson air pressure switch?
Could I have the adjustments wrong on the Johnson or Honeywell that would allow the burner to work but the fan to be non operational?
It’s all a major learning curve for me but I’d really like to help this bloke out and get his business up and running because this other tech has been absolutely appalling in first of all charging for his apprentice when she was just standing there watching and secondly not going back and getting the oven working so Ami wouldn’t have to close his business and throw out his stock.
Any suggestions would be appreciated.
I do have photos and will put them up if that’s possible.
Regards Bill
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1 Reply
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Ok, the pressure switch works off the blower air pressure. No air, no heat. It’s a safety. Now the blower wheel is in the back of the unit. But you can’t open it unless you have a new insulation gasket. More likely is that the fingers are dirty or misplaced. They go in in a certain way and order. The factory sets them up during commissioning. They are supposed to be cleaned weekly. Make sure that the end caps are set as low as possible to retain heat yet let product pass without interference. If the fingers are clean and assembled correctly, then the filler panel may not be in place. The air flow is low to prevent moving product like shredded cheese around. Basically, the fine holes of the fingers spread the heat and keep it changing to the center. The air then goes bad to the blower to be heated and resent.
I would measure the blower current to make sure it is full load. It should not be vibrating. If so it may have something in the wheel.
Now the temp wide variation may be delayed ignition, and the gas control tries multiple times till it lights. Not sure if you have hot surface or spark. Try setting the oven to a lower temperature and see if it will stabilize.
Also make sure to check the control box cooling fan. They are a muffin fan
What gas control does it have, Honeywell or Johnson?
You can monitor the power from the temp control to the air pressure switch to the high limit to the gas control. That way you can tell what is failing. Once the oven is powered, the air switch and high limit should stay closed. Only the thermostat should be switching for heat call. Both the oven safety and the control panel safety should be manual resets. (red buttons)
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