MemberFebruary 19, 2020 at 7:41 pm
We recently purchased a used Lincoln 1301 Impinger (Ser. No. 3009440) that seemed to work on first inspection. However, the thermostat doesnt seem to control the temp and continues to heat with the power turned off. I’m not just referring to the 20 min fan cycle. The temp will reach 600+ until you pull the plug. My initial thought is the contractor but i think it’s rare for NO contractor to fail closed. I’m not a service tech, it have a fair amount of experience with electronics. Any ideas?
MemberFebruary 19, 2020 at 8:47 pm
Have you checked power on both sides of the contactor when you have it powered off?
Sounds like a auction special. The controls maybe bad and they wired the contactor so when they test for a few minutes it looks like it works and you get more money.
You should call a service company before you burn your store down.
MemberFebruary 19, 2020 at 8:57 pm
I haven’t tested the the contactor yet. I’ll check the continuity tomorrow. Just to clarify, this isn’t in our store. It is merely a back up oven and is currently in my workshop. Nothing looks to have been tampered with in the electronics panel, so i believe it’s an actual electrical failure. Just not sure what.
fixbear - ADK NYMemberFebruary 20, 2020 at 5:39 am
When you say you have a 1301 Lincoln impinger, You need to tell use the serial number. There is 6 different schematics for the 1301’s, depending on serial number. But the nice thing is all of them have the heat relay directly off the lines. So you can easily determine if has a a Hung relay. There are 2 items in this machine that always have power even when the main switch is off. One is the heater relay and the other is the cooling fan and thermostat.. There should be no power to the relay coil. If this machine has been moved around a lot and maybe stood on a side to get through a doorway, something loose in the control panel may have gotten into the relay. But being a 2 pole relay it would have to be the armature jammed.
MemberFebruary 20, 2020 at 6:05 am
Serial No is in my original post. Serial Number 3009440
MemberFebruary 22, 2020 at 2:40 pm
So I tested the oven start relay and it is working fine. Tested the contactor and it was energized with unit turned off. I pulled out the contactor and opened it up and it looks fried. Had a new one overnighted and it looks totally different and didn’t operate the heating coil when installed. See pics.
MemberFebruary 22, 2020 at 2:58 pm
Tested the contactor and it was energized with unit turned off.
Was the contactor energized when unit was turned OFF…or were the contacts stuck closed when the unit was turned off?
That’s two different things.
Had a new one overnighted and it looks totally different and didn’t operate the heating coil when installed.
So the new one doesn’t work?
Your explanations are confusing.
MemberFebruary 22, 2020 at 3:08 pm
When the oven was plugged in to the power the heating element would begin to heat, even with the oven switched off. New contactor does not work.
MemberFebruary 22, 2020 at 10:04 pm
Why donâ€™t you check the secondary power to the CONTACTOR? If you had power to close the contacts then the CONTACTOR was closed. Does your model have an ETC? I believe that sends power tothe CONTACTOR, the pot switches control temp. Does the machine, when turned on, run normal and cycle temp?
There are a lot of questions a tech asks themselves when testing.
Etc p# 369465
Where did you buy the unit? Was it sold to you as a working unit? Have you verified it is wired correctly following a wire diagram?
MemberFebruary 23, 2020 at 2:22 pm
I purchased it from PartsTown. The description listed item as OEM.
fixbear - ADK NYMemberFebruary 22, 2020 at 10:11 pm
Did you maybe move the air pressure switch hose or is the high limit tripped from the run away.
fixbear - ADK NYMemberFebruary 22, 2020 at 10:15 pm
BTW, Your new relay looks to be a mercury displacement relay. It has to be veritcal and the right side up to work.
MemberFebruary 23, 2020 at 2:24 pm
Yep thatâ€™s what happened. New contactor works, however the heating element is still heating up without the power switch turned on. When power switch is on, the heating element does not respond to temperature dial setting.
MemberFebruary 23, 2020 at 9:27 am
Checking if there’s power going to the coil of the contactor when the unit is off would be the first thing to check.
I’ve seen contactors welded together before, it happens, especially if they are undersized for the load.
How is the new one not working? Is there no power to the coil? Is it the wrong contactor with the wrong coil voltage?
MemberFebruary 23, 2020 at 2:26 pm
I had inadvertently unhooked the air pressure switch hose. With that problem resolved, the new contactor does work, however the heating element is still heating up without the power switch turned on. When power switch is on, the heating element does not respond to temperature dial setting.
MemberFebruary 23, 2020 at 3:52 pm
Do these things, in this order:
Remove unit from power.
Remove both fuses, F1 and F2.
On the back of the oven, remove the cover that’s over the motor- it’s a little complicated but do it.
Trace the 2 wires from the element- they *have* to go to the top (or bottom, I forget) of your new contactor. No where else and no other wires from anywhere connect to those terminals.
It they look proper, you have a stuck contactor. Disconnect those 2 wires from the contactor, insulate. Apply power to the unit (which still has no fuses in place).
Get back to us with results. 🙂
By any chance you didn’t mount the new contactor upside-down, did you?
MemberFebruary 23, 2020 at 3:25 pm
What controls the heating element?
MemberFebruary 23, 2020 at 3:40 pm
Iâ€™m not sure how to answer that question. Iâ€™m guessing something is stuck causing the contactor to be always closed when the unit is plugged in.
fixbear - ADK NYMemberFebruary 23, 2020 at 7:22 pm
Again, read the schematic. it is hooked directly to the lines via the mercury contactor.
MemberFebruary 23, 2020 at 5:05 pm
Oooooookay, well that’s not good. It’s a lot better to trouebleshoot when you have a pretty good understanding of what the machine is doing and what the components are doing.
Looking at the wiring diagram, it seems like there’s a temperature potentiometer.
R2 which it says is the relay for the heating element might be stuck closed or welded shut, you should take a look at it.
Is the “relay” what we are calling a contactor? In which case, nevermind that.
But look, according to your diagram, R2 controls the element, so if it’s staying on, somehow those 2 contacts are closed or that same circuit is being made up somewhere else unintentionally.
You can also ohm out the wires coming from the element back to L1 and L2 and try to trace it’s path back.
MemberFebruary 23, 2020 at 6:53 pm
Sorry, i thought you were asking were the power was coming from that causing the contactor to stay energized (ie, what is stuck open).
MemberFebruary 23, 2020 at 7:19 pm
Okay, not quite.
Good, so why don’t you try this; turn off the power to the unit, then ohm out from L1 and L2 to the element and trace where it’s coming from?
fixbear - ADK NYMemberFebruary 23, 2020 at 7:20 pm
Olivero, you notice in my linc above on the 20th page 7 that the heating is unfused and only switched by the mercury contactor. That contactor is controlled by the temp control. So there has to be a miss wire or the main switch is not opening. That would also explain the lack of control.
fixbear - ADK NYMemberFebruary 23, 2020 at 7:28 pm
Being the air pressure switch stops the contactor from closing, The wiring on the line to the temp controller via the main switch is not right. Somehow there is power going to the contactor without the main switch closed.
MemberFebruary 23, 2020 at 7:34 pm
@olivero was on the right track, but thereâ€™s just not enough â€œtechnician-likeâ€ communication happening here.
SOâ€¦LOOK at the schematic Olivero posted:
- The power switch should be the first component to supply voltage necessary for BOTH heat contactor coil input circuits.
- When the power switch IS closed, it immediately supplies L1 line voltage to the heat contactor coil.
- When the power switch IS closed, it supplies L2 line voltage to the electronic temp control. The electronic temp control (ETC) supplies L2 line voltage to the OTHER side of the contactor coil. There are numerous safety components in this leg, but those donâ€™t seem to be questionable.
YET â€“ what weâ€™re reading from YOUR description is that the heat contactor is getting input voltage for the heat contactor to operateâ€¦DESPITE an OPEN power switch!
Either one of THREE things are happening:
- The brand new mercury contactor is installed upside-down.
- You have a bad power switch AND a bad ETC.
- The unit mis-wired and needs to be gone through using a wiring diagram.
After writing all of the ABOVE, I went back and looked through this thread to find that I havenâ€™t seen a SINGLE voltage reading to indicate youâ€™re knowledgeable on how to use one.
- If you’re NOT, then I canâ€™t help you.
- If you ARE, then try using the schematic.
This is a ridiculously simple heating circuit. If youâ€™re just NOT understanding it, then do as @Coolertapt and just call a service company.
MemberFebruary 23, 2020 at 7:38 pm
Thanks, I appreciate the help.
MemberFebruary 23, 2020 at 7:57 pm
I wrote that several hours ago and I easily get impatient.
Sorry about that….
Helping to troubleshoot by READING, then pounding away on a keyvboard is further aggravation, since I’m not THERE – looking over your shoulder and seeing what you’re seeing.
I don’t know your skill level or skill set, but with your proclaimed electronics background, I was expecting a bit more communication.
Nonetheless, whatever further help you need – don’t let me be the one to dissuade you from asking.
Furthermore, whatever you determine to be the cause, please still share it with us.
ALL of us are still capable of making mistake, so don’t hide yours. We cann learn from yours as well as ours if you share it.
MemberFebruary 23, 2020 at 7:34 pm
Ok so here is what i know so far.
1) The original contactor was melted and stuck closed (see pic above.
2) I installed the new contactor upside down so that explains why it was staying on as well.
3) Element is wired properly.
4) Now that the contactor is installed correctly, it will not close as it should (heating element not heating) when oven is turned on.
So that leaves the ETC or the temperature potentiometer as being bad I think.
MemberFebruary 23, 2020 at 8:01 pm
I don’t think there’s anything bad on this thing just yet, do you have a meter, can you do readings? Ohms, volts, etc?
MemberFebruary 23, 2020 at 8:14 pm
MemberFebruary 23, 2020 at 8:29 pm
Now you’re getting somewhere.
The potentiometer can be easily tested with an anolog ohmmeter. Follow th testing steps on pg 42 of the manual.
Same for the thermocouple. However, your meter might not be able to read such low DC milli-volts. Try reading it with an ohmmeter to give you an idea of the general condition of it. It should be just a few ohms vs anything higher will prove it’s bad.
MemberFebruary 23, 2020 at 8:38 pm
Unfortunately i canâ€™t work on this anymore tonight, but Iâ€™ll give your suggestions a shot tomorrow. My multimeter will read millivolts so I should be able to trouble shoot those items. Interestingly I just looked at the ETC and itâ€™s wired per the 200/208V schematic on the wiring diagram. My voltage measures 240v could this be causing me issues?
fixbear - ADK NYMemberFebruary 23, 2020 at 7:46 pm
The power switch should be the first component to supply voltage necessary for BOTH heat contactor coil input circuits.
That’s not correct on this machine. The heat contactor is un-switched and un-fused. It’s the contrlo curcuit and fans that are fused and switched off by the main switch.
MemberFebruary 23, 2020 at 8:02 pm
What gets ME is that the safety train isn’t designed to intervene if there’s a failure on the primary control side.
There sould be another contactor for safety reasons.
I’ve seen this in other equipment. In FACT…one caught FIRE at our property for that very same reason. Everyone had gone home and assumed the unit was off. But…the heating element wasn’t.
MemberFebruary 23, 2020 at 8:00 pm
Or itâ€™s wired for 208…
fixbear - ADK NYMemberFebruary 23, 2020 at 8:06 pm
Nate, the only way this could happen is if the main 2 pole switch was not opening or was jumpered on the L1 leg. There by allowing the time delay to backfeed the temp control. Test the main switch.
MemberFebruary 23, 2020 at 8:08 pm
Did this problem just occur recently?
Before you rewire anything, think about it, did this work in the past?
MemberFebruary 23, 2020 at 8:11 pm
I recently purchased it used. Itâ€™s never worked correctly while Iâ€™ve owned it.
MemberFebruary 23, 2020 at 8:50 pm
Ah how I hate how these topics scroll down in subcategories everywhere.
Scott! Can we fix that? Just make every post succeed the next so you just scroll to the bottom for the latest? It’s so confusing having to read in between replies to see what the last guy said.
Okay, bedtime, it’s a good thing, lol.
Good to know, so now we know, 240V Is not incorrect, you have 2 hot legs coming in so it’s single phase 220/240 the only thing that would act up with messed up voltage would be your element but it’s working when fed directly, we know that.
Now, it’s very, very easy to get caught in the “OH! This is wrong, gotta fix that, OH! this isn’t wired right, gotta fix that” type loop and then you start blowing stuff up, I’ve done it.
We need to find what’s broken, test every compoent like what’s being recommended using the manual, if you verify EVERY component is working properly THEN we can talk about the wiring being a problem.
Swapping wires around thinking “it goes there” can blow stuff up faster than an 8 year old with a water gun in an electronics store.
MemberFebruary 23, 2020 at 8:56 pm
I agree the reply hierarchy needs to be fixed itâ€™s very frustrating. Iâ€™ll check each component and check back here before messing with any of the wires. Thanks to everyone for the help!
MemberFebruary 23, 2020 at 9:01 pm
If you need help on how to test components, ask away, assume nothing.
Someone once told me “You can’t have checked everything and found nothing” or something like that, I remind myself of that a lot.
MemberFebruary 23, 2020 at 9:12 pm
I didnt go through the wall of responses, but did you check to see if your switch to turn the machine off actually works?
I now went through “the wall” and it was stated earlier.
MemberFebruary 23, 2020 at 9:18 pm
Also you mentioned it just continues to go up, the thermostat also might have failed which wouldn’t allow the machine to know it has reached the temp you set it to.
These are the things I would check first before getting into taking the thing apart to “look deeper”
MemberFebruary 25, 2020 at 11:17 pm
If I’m following the thread correctly, now that you’ve changed the heat relay, and everything is wired correctly, the relay isn’t pulling in to energize the element.Is the fan running and if so , is the pressure switch closing? That looks to be the circuit… etc, pressure switch, heat relay. if the relay won’t pull in, problem should be in one of those.
MemberFebruary 25, 2020 at 11:21 pm
Oh… and also the high limit. I would almost bet that if you had a melted relay… your high limit cooked.
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