Electrical Wiring in the Home/Air handler wiring


QUESTION: I replaced and wired in two heat sequencers on a lennox cbm30-51-1p. The wires on the top side of the wiring harness I can figure out where the go. I have a yellow,orange, and red in the 1,2,3 and 3 holes of the harness then a slightly bigger gauge red,brown and black wires also. The end of the harness which plugs in from the transformer side is ok.

ANSWER: Andrew

These are all OEM colors, which mean something to Lennox,  but as far as any standard wiring scheme Red Brown and Black could mean anything,      

You say "I have a yellow,orange, and red in the 1,2,3 and 3 holes of the harness" then a slightly bigger guage set colored the same also.

Help me understand yellow orange and red in the 1,2,3 and 3 holes of the harness....

I count three colors and four holes somehow,      


I found this worthless brochure above,  can you point to the wiring diagram,  is there one to point to?   

I would say right off the top that the Y O R  colors at the smaller guage end up with the larger guage in parallel someway.

Almost sounds like a high speed fan and a low speed fan,  the higher speed with the larger guage and the lower speed with the smaller guage.

Then you talk about a transformer which is wired OK,    so is that a control transformer of some kind?

I will help you with this,   but you replaced two heat sequencers,  where is the wiring diagram?

Heat sequencer with identically colored wires,  but two guages,  tells me one set is obviously handling more current than the smaller guage,     so maybe the smaller guage engages then is dropped out in place of the larger guage,     or again as they are the same colors  they may end up in parallel,  but without a cut away drawing or connection diagram or SOMETHING,    I am not sure how to help guide you.

I see this statement  in regards to the CBM30-51-1P   

Optional Electric Heat —A wide
range of electric heat options are available
including the EvenHeater™ Supplemental
Heater to provide backup resistance heat.

Then I found this :


If you can help me dial into the exact model you are dealing with I am sure between the two of us,  figure out what goes where and why.

I am just a bit shy of information, there are so many models and sub models, it is impossible to keep every wiring scheme,  even Lennox has issues with models  as they put a disclaimer at the bottom of nearly ever page that says    due to quality control and advancements no wiring diagram can be considered permanent and may be changed   [in engineering] at anytime without notice,          which is typical         

If you can at least guide me to a wiring schematic or anything that I can refer to, we will figure this out,         

---------- FOLLOW-UP ----------

QUESTION: Well let start by saying that I ran a call for no heat. The sequencers had 24v wires jumped to the 240v side of the next sequencer. It was wired all kind of ways. 4 heating coils with 3 double stack sequencers and one single stack. A mess!! So I wires one heat sequencer per coil or heating element. Would that cause overload? Anyway I didn't mess with any of wires coming from side of the harness that wires into the step down transformer and Tstat terminals and so on. The other side of the harness I can read #1 which a yellow wire in it #2 orange #3 red the there is another red which I have to the breaker black I have to the other side of breaker. Then there is a brown. I Know they go to the sequencer just don't know which go to 24v or 240v. When I click breaker it buzzes but doesn't trip. Like an overload. Hope this helps. Model #CBM30-51-1P lennox.


Check these links out:


https://www.youtube.com/watch?v=lliFA8TwCgM     VIDEO

Let me get honed in the exact model  

Do you have this:?


Now I am understanding the issues better,  let me ask this,   do you think the original was OEM or engineered after on the fly?

Your approach with one HS per coil, seems logical,  and I don't see that causing an overload,

Let me ask you this,   could you get an amprobe on the breaker and get a current measurement?

The buzzing yet no trip, sounds like low control voltage, sometimes elements will act like an inductive load and not a resistive load,     

Let me dig through some more Lennoz stuff, and you can use my personal email   it is much simpler if we need to go back and forth,  allexperts is truly a great service,   all they want is to pay forward and help people,   never ask for anything,  so once you make contact with some help,  the only thing that won't benefit someone down the road is the logistics we use to figure this out,    I am thinking this is so rare it won't be a problem that will be searched, so if the steps we take are not on here,  it probably is no big deal,          so feel free to use my personal email which is at the bottom of my screen  or wbwill@sbcglobal.net,  just put in the subject line  Lennox heat seq from allexperts or something to that effect so I know it is you and can refer back to any original info,       

Much better picture in my mind of what you are dealing with,  and mess is a perfect description,      but that is why you are doing it,   it takes the above average to even attempt to deal with this kind of issue,   my kind of technician,     

Give me a bit,  I just sold my two businesses and took a position with the buyer to teach them how to run a motor repair shop, and it is nutsville,  but I will get on this maybe even right now and see what I can dig up,  but if I miss a day or so getting back  don't worry I will and I know it is a furnace and winter,  so no time to mess around,  but sometimes they have me tied up in knots,     I have been here for three weeks and just got out of my 11th meeting,   not 15 minutes either    like 4 plus HOURS     yikes what have I done to myself?

We will get this figured out,   bare with me,  
About Electrical Wiring in the Home
This site answers questions related to home electrical wiring, home wiring, general electrical help,and other electrical questions related to aleternating current (AC). You can find help on the National Electical Code, home electrical issues, wiring electrical outlets, installing lighting, electrical grounding, and general electrical help for do-it-yourself projects not require an electrician. If you do not see your home electrical wiring question answered in this area then please ask your electrical wiring question here

Electrical Wiring in the Home

All Answers

Answers by Expert:

Ask Experts


Will Babbitt


Electrical issues of all types, wiring, control, appliances, components, specialty in Electric MOTOR or APPARATUS trouble shooting, electric motors, electrical problems, single phase, three phase, DC, capacitors, elevator MG-Sets, modifications, reverse engineering, VFD Drives, single to three phase convertors. Repair of most any electrical/mechanical/electronic apparatus, OEM, AC, DC, Industrial Applications, Three phase, single phase failure mode, determining the root cause of the equipment failure BEFORE failure repeats, Antique appliances, electric motors, fans, ceiling fans, base mount fans, poor equipment performance, Modifications, habitual failures, vibration, redesign, obsolete issues, collectible items restored, rewinding. Owner of EMR Repair Inc www.emrrepair.com More information on electric motors, under Engineering/Motors Ask about any electrical or mechanical problems in the home, office, or even at your work. B2B or business to business CONSULTING I can do but it would be a much more complex issue, that would require a significant amount of time. repair@mearservice.com from there we can discuss and begin work on about anything. Industrial electric motors, controls, troubleshooting, vibration, alignment, any type of industrial or commercial electric/electrcical equipment For the home owner, renter, apartment if you have odd things going on, describe to me, photos are normally very helpful, appliances, heating and air conditioning issues, light switches, installation, DIY PROJECTS FOR THOSE NOT EDUCATED IN ELECTRICAL, we can do some things, but for safety and sanity reasons, I may refer you to a local electrician, and help you find one, help you with pricing and even speak directly with anyone you hire if you have issues,


Over thirty years with a major repair and sales company, VP of Operations, and former owner of my own specialty repair shops, MEAR Services local to Kansas City Missouri EMR Repair Inc., located in Kansas City Missouri, 2014 sold both businesses to JCI Industries, Lee's Summit Missouri wbabbitt@jciind.com Evaluation and repair of electrical/mechanical apparatus. Electrical and mechanical repairs, trouble shooting including, vibration and balance issues. About.com provides this service, and the huge costs to provide help on about any subject. They provide the servers, the people to vet the experts, costs that would be the same as operating a good sized business, They should be appreciated for what they do, the huge costs and the great help they provide for free, Electric motor questions, can be answered here but there is a dedicated category that has other experts to help and add to a solution. Other common questions, are noises in the walls, breakers tripping, devices not starting or shutting down for no apparent reason, smoke alarms buzzing, thermostat change outs, or sizing wire or needing information for a new project, but anything can be resolved, anything, with enough effort and patience, DIY, with electrical is possible, but in most cases the use of a simple ohm meter or volt meter is needed, they can be purchased at any hardware store for a few bucks. If you have smoke, or smell smoke, don't be writing me, call 911 the Fire Department has no problem looking for smoke smells, better then spraying water on a blazing fire. DO NOT GET CAUGHT INVESTIGATING AND TRAPPED IN A BASEMENT LOOKING FOR A BLOWER FAILING< As to the tip jar, it is up to you, it is appreciated, every expert spends out of pocket that I know, we spend on IP time, computer wear, printing documents, books, and of course our time, but if we prevent a $400 service call, we did well,

Former IBEW, EASA, IEEE, UL, ..............


10 plus years, various Technical Schools, followed by Industrial College Credit and non Credit Courses, electronics courses, experience in most any electrical apparatus, electric motors and generators, AC OR DC, fractional to above 5000HP, other electrical apparatus, slip rings, sleeve [plain] bearings, lubrication, identification-no data plate, control components, service and sales. I have continued night schools for decades, the list is extensive. I have been in the business of repairing most anything with wires or mechanical parts for decades, I have some helpful hints and directions you won't have to dig up. Or hopefully not have to pay a huge service call invoice to find.

Awards and Honors

Past/Present Clients
Federal Government, National Weather Service, NOAA, Commercial Power Plants, Major Vehicle Manufacturers, Printers, Other industrial and Commercial Businesses

©2016 About.com. All rights reserved.