How to Identify and Wire a Heat Only Unit - Electric Furnace
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- Опубліковано 9 лип 2024
- In this video I try to explain how to identify and wire a "heat only" system. This particular unit is a electric furnace with a 5 KW kit. It is about as easy as it gets as far as low voltage wiring for an HVAC technician. So many technicians that I see will mistakenly wire in "circuits" that aren't needed. They see all these wires in the thermostat wire sheathing and just go crazy wiring what they have memorized on a white board. You have to be able to identify what unit you are working with in order to know what terminals/circuits are involved. Once you have that figured out you can pick the proper thermostat and start making things work!
In order to save time, I will try to add to this later by posting a troubleshooting video on the same unit.
Here is how I would put the Sequence of Operation for this unit (generically speaking of course):
Fan Only Mode
1. Power “ON”
2. Move “Fan” switch from “Auto” to “On” (the switch from “R” to “G” closes)
3. 24 Vac passes across “R” to “G” and energizes the Indoor Fan Relay Coil
4. The switches on the I.F.R. react and do the opposite of their normal position. (The N.O. switch(es) close, The N.C. switch(es) open)
5. The high voltage power passes through the N.O. switch that has just closed and powers the Indoor Fan Motor.
6. If the motor is good then the motor turns “ON”
7. Move “Fan” switch from “On” to “Auto” (the switch from “R” to “G” opens)
8. 24 Vac stops passing across “R” to “G” and de-energizes the Indoor Fan Relay Coil
9. The switches on the I.F.R. react and go to their normal position. (The N.O. switch(es) open, The N.C. switch(es) close)
10. The high voltage power stops passing through the N.O. switch that has just opened and stops powering the Indoor Fan Motor.
11. The motor turns “Off”
Heating Mode - Electric Heat
1. Power is “ON”
2. Thermostat is in the “HEAT” position.
3. Thermostat senses a fall in room temperature below the set point.
4. The thermostat initiates a “Call for heating” and the switches from “R” to “W” closes. 24 Vac passes across “R” to “W” and energizes the Heat Relay Coil.
5. The switches on the Heat Relay react and do the opposite of their normal position. (The N.O. switch(es) close, The N.C. switch(es) open)
6. The high voltage power passes through the N.O. switch(es) that has just closed and powers the Electric Heat Strip. At the same time, high voltage power also goes into the N.C. switch on the Indoor Fan Relay.
7. If the electric heat strips are good then they turn “ON”, If the fan motor is good, then the Indoor Fan Motor is “ON”.
8. Thermostat senses a rise in room temperature so that the set point is met.
9. The thermostat stops “Call for heating” and the switches from “R” to “W” open. 24 Vac stops passing across “R” to “W” and de-energizes the Heat Relay Coil.
10. The switches on the Heat Relay react and go to their normal position. (The N.O. switch(es) open, The N.C. switch(es) close)
11. The high voltage power stops passing through the N.O. switch(es) that has just open and stops powering the Electric Heat Strip. At the same time, high voltage power also stops going into the N.C. switch on the Indoor Fan Relay.
12. The Electric Heat Strips and the Indoor Fan Motor turn “OFF”
Excellent explanation
Awesome. Thanks for checking it out.
Awesome video
Thanks Bigg Dogg.
explain how to wire the Nordyne Mobile Home electric furnace to a modern heat pump condenser such as a goodman or rheem
Do I need additional voltage if I add a heat strip to my unit?
Maybe an additional circuit from the panel/sub-panel. Depending on the wire size that you currently have and what you are going to need for the heat strip kit. Probably have to get with the local mechanical/electrical contractor if you don't know.
My furnace went out and I'm in Iowa and it's Sub-Zero my furnace is he only electric it has the green blue brown white and red wire coming out of the unit and then the one that comes out the wall which I believe goes to the thermostat is only got three wires and it's kind of white red and kind of bluish green I don't know how do I put them back together and turn my thermostat
1st - Sub zero...call somebody if you haven't already! (Only 12 for me this morning and that is cold enough.) Probably a wait but at least you are in the mix. 2nd - if it is all electric is is likely a heat sequencer that is an issue but also sounds like you got some wiring concerns? If you want to take a couple pics and email me @ ---------, i can try but definitely call someone! Pic of the thermostat, wiring on each end, more the better but whatever you got and can get will be a start. No promises but we can try it.
Can this be used as electric forced air furnace for a 1500 sq home? I live in Michigan was looking around for the best electric furnace options getting rid of gas. Thanks
It could depending on exactly how much/many heat strips (in Kilo-Watts) you had in it. But I would think you would be better off with gas heat in that part of the world. Gas should be more efficient for the money. I would consider talking to a local professional about changing from gas to electric.
I have two wires from my thermostat. Where would they hook to?
2 wires sounds like some type of communicating thermostat? Most any system has more than 2 wires on the sub-base. I would need more info to have a better idea. Colors of the wires or something ...
Two wire is for a heat only electric furnace
Im trying to switch to electric heat only from gas. Any sugestions?
Not knowing all the details as to why...I have just one if it were me. DON'T!! If you have natural gas already...it is warmer and cheaper than electric heat strips. If it is propane, the cost will be more than natural but it is still much warmer. If you are going to replace a gas system with electric, consider a heat pump with heat strips maybe. Forgot to mention that you will likely have to upgrade the electric circuit in your house to properly hook up to electric heat as it pulls more amperage typically.
Why connect the common wire if you don't have a wifi tstat?
I hate wasting batteries. I'd rather use them in my TV remote.
IS THAT A HONEYWELL 3000 THERMOSTAT ?
As bad as I hate to say it...yes. it was already on the unit. I am not a fan! I liked the Pro 5000.