Mitsubishi Heat Pump Troubleshooter
Answer a few questions about what your system is doing and get the likely cause, what you can safely check yourself, and when to call. Built by Superior CO-OP HVAC's Mitsubishi-certified service team.
- Mitsubishi Diamond Contractor ELITE
- 12-year parts & labor warranty
- 180-Day Comfort Guarantee
- Veteran-owned since 2013
Trouble loading? Open the troubleshooter full-screen.
Common symptoms, likely causes, and what to do
The tool above walks you through these one at a time. Here is the same logic in a table you can scan — and the point at which to stop and call.
| What you notice | Most likely cause | Safe check | Call us when |
|---|---|---|---|
| Blowing cool air in heat mode for 5–15 minutes | Normal defrost cycle on a frosty outdoor coil | Wait it out; listen for the compressor to resume | It happens every 30–40 minutes or lasts over 20 minutes — defrost explained |
| Not heating at all | Mode set to AUTO/COOL/FAN, dead remote batteries, tripped breaker, outdoor unit buried in snow | Set HEAT, replace batteries, reset breaker once, clear snow 18 in. around the unit | Still no heat after those checks — full checklist |
| Indoor light blinking | Fault code (communication, sensor, drain, outdoor fan/compressor) | Count the blinks, note the pattern, power-cycle once at the breaker | The pattern returns — what the codes mean |
| Weak airflow | Dirty filters or coil, fan speed on low, closed vane | Wash the filters (how), set fan to AUTO/HIGH | Airflow stays weak with clean filters |
| Water dripping from the indoor unit | Clogged condensate drain or line, unit out of level | Turn the unit off to stop the drip | Right away — water damage is the expensive part |
| Musty or sour smell | Biofilm on the coil or in the drain pan | Run FAN mode 30 minutes after cooling; clean filters | Smell persists — coil cleaning is a service visit. More |
| Outdoor unit iced solid | Failed defrost, low refrigerant, blocked drainage under the unit | Turn it off; never chip ice off the coil | Same day — ice can bend the fan. More |
| Loud grinding, rattling or screeching | Fan hitting ice or debris, failing bearing, loose panel | Turn it off | Before running it again |
| Short cycling (starts and stops every few minutes) | Oversized unit, dirty filters, thermostat placement, low refrigerant | Clean filters, move the remote/thermostat away from drafts | Cycling continues — efficiency and compressor life suffer |
| Electric bill jumped | Backup heat running, dirty coils, extreme setpoint swings | Keep a steady setpoint; clean filters | Bill stays high — ask for a performance check. What it should cost |
Superior CO-OP HVAC repairs Mitsubishi systems we installed and systems other contractors installed. The trip and diagnostic charge is $250, you get a written quote before any work, and the 24/7 line (518) 333-7431 books the visit any hour. Heat pump repair →
Rebates Available
New York homeowners switching from oil, propane or electric baseboard to a Mitsubishi cold-climate heat pump qualify for National Grid or NYSEG rebates, and Vermont homes qualify through Efficiency Vermont plus utility bonuses. Rebate amounts change by program and tier — we tell you exactly what your home qualifies for at the free in-home estimate and handle the entire application for you.
Don't take our word for it
“This company operates like a functional family. Everyone is skilled, knowledgeable, and has a healthy attitude and work ethic. They were here when they said they'd be and did what they said they'd do with total attention to detail. There's no substitute for peace of mind.”
“Great interaction all around with the company. Had them install a mini split system. Excellent customer service — from the estimate on site visit to the install, each individual was kind and professional.”
“Superior CO-OP HVAC installed my Mitsubishi mini split and did a great job. It's so quiet and cools my place quickly. I highly recommend them.”