Uploaded April 2026 | Updated September 2026, 3 weeks ago
In this video, I walk you through a full MRCOOL heat pump install, wiring, and startup — including what the system should actually do when you power it on.
A lot of people think something is wrong when auxiliary heat kicks on, especially after switching from cooling to heating… but that’s not always the case.
I’ll show you:
✔️ Correct thermostat wiring (2H/1C heat pump setup)
✔️ How to wire the air handler, outdoor unit, and gas furnace (dual fuel)
✔️ A full pre-startup checklist you should NEVER skip
✔️ What to expect during first startup
✔️ Why AUX heat turns on (and when it’s normal)
If you’re installing or troubleshooting a hybrid MRCOOL system, this will save you time, money, and headaches.
⚡ System Covered:
MRCOOL Universal Heat Pump + Gas Furnace (Dual Fuel Setup)
⚠️ Common Mistake: T1 Sensor not installed will keep this entire system from operating!
Aux heat running doesn’t always mean something is wired wrong — I explain exactly why in this video.
👇 Have Questions?
Drop them in the comments — I answer as many as I can.
👍 If This Helped:
Like the video & subscribe for more real-world how to videos and troubleshooting.
📥 Download the Wiring Diagram + Startup Checklist:
00:00 Intro
00:40 Step 1 - Removing old Unit
01:21 Step 2 - Installing furnace and A-coil in place
02:56 Step 3 - Attaching return air
03:32 Step 4 - Condensate, intake/exhaust, gas, power
04:23 Step 5 - Mount outdoor unit
05:00 Step 6 - Connect lineset and power
06:29 Step 7 - Wiring the controls
09:27 Step 8 - Install A-coil Condensate drain
09:46 - Step 9 - Program Thermostat
10:30 - Operation and Troubleshooting
SHOP WHAT WE USED
shoplowes.me/4aLV0Zr
DIY Building + Contracting Community
patreon.com/mrpostframe
RENOVATION MATERIALS
shoplowes.me/49k0RGj
TOOLS FOR THE JOB
amazon.com/shop/marshallremodel/list/1368UK4EAEVBY?ref_=cm_sw_r_cp_ud_aipsflist_5WJTQAF3M8ZCYY1DCHJK
BUILD PARTNERS
mrpostframe.com/about-4
Hammer
bosshammerco.com/?ref=opUzOPCAaxHRCw
Use code for a discount: MRPOSTFRAME
Safety Glasses/Sunglasses
iwearhyspecs.com/MRPOSTFRAME10
Use code for a discount: MRPOSTFRAME10
Work Boots
rockroosterfootwear.com/?ref=dbHZ1eOSlWw9
Use code for a discount: MRPOSTFRAME
CONNECT
PO Box 11
Winterset, IA 50273
instagram.com/mrpostframe
facebook.com/mrpostframe
tiktok.com/@mrpostframe
Sound Stripe - 9U4KQJBJGVQ7E1QF
In this video, I walk you through a full MRCOOL heat pump install, wiring, and startup — including what the system should actually do when you power it on.
A lot of people think something is wrong when auxiliary heat kicks on, especially after switching from cooling to heating… but that’s not always the case.
I’ll show you:
✔️ Correct thermostat wiring (2H/1C heat pump setup)
✔️ How to wire the air handler, outdoor unit, and gas furnace (dual fuel)
✔️ A full pre-startup checklist you should NEVER skip
✔️ What to expect during first startup
✔️ Why AUX heat turns on (and when it’s normal)
If you’re installing or troubleshooting a hybrid MRCOOL system, this will save you time, money, and headaches.
⚡ System Covered:
MRCOOL Universal Heat Pump + Gas Furnace (Dual Fuel Setup)
⚠️ Common Mistake: T1 Sensor not installed will keep this entire system from operating!
Aux heat running doesn’t always mean something is wired wrong — I explain exactly why in this video.
👇 Have Questions?
Drop them in the comments — I answer as many as I can.
👍 If This Helped:
Like the video & subscribe for more real-world how to videos and troubleshooting.
📥 Download the Wiring Diagram + Startup Checklist:
00:00 Intro
00:40 Step 1 - Removing old Unit
01:21 Step 2 - Installing furnace and A-coil in place
02:56 Step 3 - Attaching return air
03:32 Step 4 - Condensate, intake/exhaust, gas, power
04:23 Step 5 - Mount outdoor unit
05:00 Step 6 - Connect lineset and power
06:29 Step 7 - Wiring the controls
09:27 Step 8 - Install A-coil Condensate drain
09:46 - Step 9 - Program Thermostat
10:30 - Operation and Troubleshooting
SHOP WHAT WE USED
shoplowes.me/4aLV0Zr
DIY Building + Contracting Community
patreon.com/mrpostframe
RENOVATION MATERIALS
shoplowes.me/49k0RGj
TOOLS FOR THE JOB
amazon.com/shop/marshallremodel/list/1368UK4EAEVBY?ref_=cm_sw_r_cp_ud_aipsflist_5WJTQAF3M8ZCYY1DCHJK
BUILD PARTNERS
mrpostframe.com/about-4
Hammer
bosshammerco.com/?ref=opUzOPCAaxHRCw
Use code for a discount: MRPOSTFRAME
Safety Glasses/Sunglasses
iwearhyspecs.com/MRPOSTFRAME10
Use code for a discount: MRPOSTFRAME10
Work Boots
rockroosterfootwear.com/?ref=dbHZ1eOSlWw9
Use code for a discount: MRPOSTFRAME
CONNECT
PO Box 11
Winterset, IA 50273
instagram.com/mrpostframe
facebook.com/mrpostframe
tiktok.com/@mrpostframe
Sound Stripe - 9U4KQJBJGVQ7E1QF
