York High Limit Switch

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Old 10-25-07, 09:16 AM
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York High Limit Switch

I have a problem with my heater. It is a York Model P2MP Series (D12N0641) heater/ac unit. I have done some basic troubleshooting, but I am stuck. My indicator light flashes 4 times indicating that the high limit switch is causing the furace not to ignite, I replaced the switch and changed the filter, but the idicator light continues flashing. Any help/suggestions would be appreciated. I have called to set up a service call, but the wait is over 2 weeks and it is supposed to become cooler here in the East during that time. THANKS
 
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Old 10-25-07, 09:47 AM
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York

Many furnaces have more than one limit. Have you checked them all?
 
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Old 10-25-07, 12:17 PM
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Originally Posted by Jeeper270 View Post
I have a problem with my heater. It is a York Model P2MP Series (D12N0641) heater/ac unit. I have done some basic troubleshooting, but I am stuck. My indicator light flashes 4 times indicating that the high limit switch is causing the furace not to ignite, I replaced the switch and changed the filter, but the idicator light continues flashing. Any help/suggestions would be appreciated. I have called to set up a service call, but the wait is over 2 weeks and it is supposed to become cooler here in the East during that time. THANKS


So IOW when you reset by turning the power off then back on, it goes into lockout right away? Like Grady says, there are probably more limits or possibly rollout swtiches in that string of safeties. Can you interpret the wiring diagram and follow that circuit?
 
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Old 10-25-07, 05:57 PM
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Thanks for the suggestions.Yes, the system goes in to immediate lockout when the power is reset. I will try to follow the wiring circut to the limit switch tomorrow. Not sure if I have the know how to properly check it, but it is worth a try. I do have a lot of mechanical knowledge, just not real sharp on electircal and certainly not on gas heaters,lol. Thanks again.
 
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Old 10-29-07, 10:06 AM
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Continued Problemith 4 blink code on York

As you guys suggested, I followed the wiring diagram and found what I believe to be 3 more -one primary limit switch and 2 aux. limit switches. They are brown/tanish switch looking connections with a small reset looking button on top located between the 2 wiring connections. All are working freely. I can not locate what the wiring diagram describes as roll out switches.The air pressure switch also seems to be opening and closing properly. I lightly blew air in to the line and can hear it functioning. My normal service company says the first appointment that is available is Nov. 10th and the temp fell to 34 degrees outside last night. Again, MANY thanks for any help/suggestions tht yo might have.
 
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Old 10-29-07, 05:42 PM
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Nov. 10th?

You've gotta be kidding. I can't believe any service company is so busy they can't do a "no heat" call until then. I'd be on the phone trying to find another company. You might want to visit York's web site to see who else is a York dealer in your area.

For testing purposes only:
You can use a small wire with alligator clips on each end to jumper each side of each limit switch. Such wires are available at any Radio Shack or similar type store. To test, jump around all the switches you can find, turn off the power to the furnace, wait about 15-30seconds & turn the power back on. If the trouble code disappears, simply remove one jumper at a time until the code comes back. When it does, you've found the troublesome switch. Do not leave these jumpers in place to operate the furnace. The limits are safety devices. They do fail from time to time but you also could have a real problem.
 
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Old 10-29-07, 06:24 PM
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Thank You

Grady-Thanks so much for your prompt reply and suggestion. I will give it a try. I think the reason that I am so far down on the list is that whenever I have them out for a call-either PM or a repair, they want to sell me the maintainence agreement in their follow up calls. Since I do home repairs and can do most of the stuff required for normal maintainence, I don't feel that it is money well spent. But, I think that your suggestion there is a good one also. I am just one of those stubborn people who thinks they can fix anything and this is just not my field of expertise,lol. I replaced my water heater (gas also) last spring and it took me an hour as opposed to their 185.00 "basic" installation fee.
 
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Old 10-29-07, 07:30 PM
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Jeeper

In reality, nearly any competent service company should be able to fix you up. I doesn't have to be a York dealer. I still think I'd be calling around. Sounds like you are dealing with "Mr. Big Heating Co." Might want to try "Pop & Sons".
 
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Old 10-31-07, 07:57 AM
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Update

Well, I tried bypassing the 3 switches that I could find and then reset eveything and still nothing. The blower comes on immediately after I reset the power and the 4 light sequence (indicates open high limit switch,which I replaced with a new one). I guess that I will have to give up being stubborn and call another service company. Thanks again to the moderators and members for all of your help and suggestions.
 
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Old 10-31-07, 08:10 AM
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These people expect you to wait 3 weeks for a no heat call when it's in the 30's? That's nuts. I'd be at your house at midnite if that's what it took. You can't leave families without heat. I'm sure you've missed a limit somewhere or maybe you have an open wire. Look around in there again.
 
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Old 10-31-07, 04:24 PM
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Thumbs up

Thanks again DaddyJohn. I treat my customers like you do. That is also why guys like you and Grady spend your time here helping people.Because you CARE about people and do not let the bottom line rule your life. I have a lot of customers tell me that I am never gonna get rich charging the prices I do. But, even though I certainly like money as well as the next guy, it is not something that will cause me to just charge what I think others will pay instead of what the job is worth. Again, my SINCERE thanks to you both, not only for the help that you have given me, but for caring.
 
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Old 10-31-07, 06:46 PM
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Do you have a digital camera? If you do, take a picture of the heater compartment and a picture of the schematic and post it on here. We can help you alot better if we have a schematic and know what you are looking at.

I also agree with the guys who said any HVAC company can repair your heater. Let's face it, they all work the same and have basically the same parts, just a little different from maker to maker. The best6 way to find someone to fix your stuff is ask your friends who they use. You can look in the yellow pages, but it's kind of a crap shoot to see what kind of technician you get. The first question to any HVAC company is if there thecnicians make a commision on parts. I refused working at companies because of that. I'm a technician, not a salesman. Let me fix what is broke and not the whole unit.
 
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Old 10-31-07, 08:20 PM
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Jeeper

If you have an ohm meter & know how to use it, you can disconnect both ends of the "limit" chain, plug one meter lead into each end, & if you get continuity, all the limits in the chain are closed as they should be. If you don't get continuity, you can check each switch & each wire the same way.
 
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Old 11-01-07, 07:09 AM
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Thanks again guys, I have reached the limit of both my skill level and my patience,lol. I am calling today and finding someone. Actually, it is not about the money as much as it is the frustration factor. I am one of those people who "thinks" they can fix anything and I keep going back and trying different stuff, but obviously it is an electrical problem and above my level. I am actually thinking it is somewhre in the control board. After jumpering all of the limit switches (including the new high limit switch), and a complete cleaning and checking all of the wiring for obviousy broken links, I give up. I am going to make sure I am here when the service man comes though,lol.THANKS AGAIN FOR ALL OF YOUR HELP AND PATIENCE.
 
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Old 11-01-07, 10:03 AM
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Just for clarification, are you jumping across the safety switches with the wires still on them? If you remove the wires from the switch, then you would jumper across the two wires you removed from the switch, and not on the switch itself.

If this was already obvious to you, sorry about the post.
 
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Old 11-01-07, 05:45 PM
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Jeeper

I understand your frustration & commend you for trying as well as knowing when you are in over your head. Please post back in this same thread when you finally get it fixed & let us know what the problem was.
 
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Old 11-02-07, 06:30 AM
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Thumbs up

Hi All- Well, I am sittting here at my PC without a shirt and sweating, so my heater is working again. (I had moved the thremo up when trying to get it working and forgot to reset it after the heater was fixed,lol). The problem turned out to be the control board. The Service guy said that he had seen it before a few times that they had faulted and the signal they sent was that the high limit switch was bad. Turns out that the back of the board where the thermostat connections are had a bad section. Around 154.00 for the board and 84 for the call, so over all, not to bad. Thanks again for all of your assistance. I am going to check the board every couple of days even if I do not have a problem just to pick your brains and see what I can learn reading the posts. Ray
 
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Old 11-02-07, 03:38 PM
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Thumbs up Heat

Having heat in November is a good thing. Those control boards can really throw you for a loop sometimes. Generally they are pretty reliable but when they crap out & give you a false code, Grrrrr.
Since you have now found a service company who seem to respond promptly to a no heat call & the prices don't seem to be out of line, I suggest you develop a working relationship with them.
 
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