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airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8327
Experience:  Furnace, A/C and heat pump specialist.
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Helms /I need wiring diagram model 3400A818 elec.

Customer Question

Customer: ***** ***** helms /I need wiring diagram for coleman model 3400A818 elec. furnace.mainly wiring for sequencer
JA: Thanks. Can you give me any more details about your issue?
Customer: changed sequencer but do not have a diagram to show connections of wires
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Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

Let me know if you can open this file and if this is what you need.

Customer: replied 1 year ago.
no help ,no wiring shown for sequencer
Customer: replied 1 year ago.
no help. no wiring shown for sequencer
Expert:  airheatman replied 1 year ago.

Not sure why you are unable to see sequencer wiring.Here is a better picture showing both low and high voltage

Customer: replied 1 year ago.
diagram shows 4 yellow wires to sequencer- mine has only 2 yellow.
Expert:  airheatman replied 1 year ago.

OK lets stay on this one question.Do not open a new question as this leads to confusion on the website So lets stay here.If you only have 2 yellow wires that means you just have 10KW heat.

What is the issue you are having and do you have a meter for troubleshooting?

Customer: replied 1 year ago.
furnace has 3 heat elemets-only the center one heats even on emergence- I do have multimeter-no voltage on top or bottom elemets- good voltage on center-heating is not good.
Expert:  airheatman replied 1 year ago.

Can you upload me a picture showing where we are checking and what voltage we have?

Customer: replied 1 year ago.
roger helms -in reference to your last request .i can not send picture this unit is 30 miles from me. i checked the voltage at the limit switch on all elements,had in the 240v range on center element and 0 volts on upper & lower elements in heat mode &emergencey heat. let run awhile in both settings and still got the same results with multible checks.
Expert:  airheatman replied 1 year ago.

Turn off power to unit.Disconnect elements and check the ones that are not coming on for continuity.If we have continuity on elements, most likely sequencer is defective.To test the sequencer. Check for 120v on each side of sequencer.

Customer: replied 1 year ago.
i still need to see wiring diagram mainly for wires on sequencer since i dont know which wire goes where according to colors .i had to remove sequencer to take to parts supplier at their request to be matched. then i lost my way,sorry but my plan did not work. this the reason for contacting you to start with for access to diagram of wiring. Thank You!
Expert:  airheatman replied 1 year ago.

Wiring is pretty simple. You should be able to wire using what I sent.The diagram shows four elements but id you only have 3, disregard the 4th element on diagram. If I have a pic it would be easy to mark them for you.

Here is what you will have.

1. White from thermostat to sequencer coil(Low Voltage)

2. Blue (common)from transformer to other side of sequencer coil(Low voltage)

3. Wire from breaker to M1

4.Wire from M2 to one element

5.Wire from breaker to M3

6.Wire from M4 to next element

7.Wire from breaker to M5

8.Wire from M6 to last element

9. Grey wire from fan relay also connected to [email protected] so blower comes on with first element.

10. Orange and blacks from breakers to other side of elements

Expert:  airheatman replied 1 year ago.

9. Should say Grey wire from fan relay also connected to M2 so blower comes on with first element

Customer: replied 1 year ago.
ok will let you know the outcome . thanks!
Expert:  airheatman replied 1 year ago.

Just let me know.I am here most every day and glad to help