Durham Region Air Conditioning Repair, Service and Installation
In some cases air conditioning system repair can be rather complicated for an average user. However, some of the typical problems are not that serious and don't require much more than basic skills. Even if you don't feel like troubleshooting your Rheem air conditioner on your own, you may use the check list below to gain a better understanding of the issue and not let a service company take advantage of you.
rheem A/C error codes
CODE: 0- Standby.
RESULT: No command for unit operation.
FIX: Normal operation.
RESULT: No command for unit operation.
FIX: Normal operation.
CODE: c - First Stage Cooling.
RESULT: Unit has received a command for first stage cooling.
FIX: Normal operation.
RESULT: Unit has received a command for first stage cooling.
FIX: Normal operation.
CODE: c Flashing.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for first stage cooling during an active anti-short cycle timer or minimum run timer. Wait until unit timer has expired or press the TEST button to defeat short cycle delay..
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for first stage cooling during an active anti-short cycle timer or minimum run timer. Wait until unit timer has expired or press the TEST button to defeat short cycle delay..
CODE: C - Second Stage Cooling.
RESULT: Unit has received a command for second stage cooling.
FIX: Normal operation.
RESULT: Unit has received a command for second stage cooling.
FIX: Normal operation.
CODE: C Flashing.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for second stage cooling during an active anti-short cycle timer or minimum run timer. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for second stage cooling during an active anti-short cycle timer or minimum run timer. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
CODE: h - First Stage Heat Pump.
RESULT: Unit has received a command for first stage heat pump.
FIX: Normal operation.
RESULT: Unit has received a command for first stage heat pump.
FIX: Normal operation.
CODE: h Flashing.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) action.
FIX: The unit has received a command for first stage heat pump during an active anti-short cycle timer or minimum run time. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) action.
FIX: The unit has received a command for first stage heat pump during an active anti-short cycle timer or minimum run time. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
CODE: H - Second Stage Heat Pum.
RESULT: Unit has received a command for second stage heat pump.
FIX: Normal operation.
RESULT: Unit has received a command for second stage heat pump.
FIX: Normal operation.
CODE: H Flashing.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for second stage heat pump during an active anti-short cycle timer or minimum run timer. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
RESULT: Anti-short cycle timer (3 minutes) or Minimum run timer (30 seconds) active.
FIX: The unit has received a command for second stage heat pump during an active anti-short cycle timer or minimum run timer. Wait unit timer has expired or press the TEST button to defeat short cycle delay.
CODE: d - Defrost Active.
RESULT: The unit is undergoing a defrost cycle.
FIX: Normal operation.
RESULT: The unit is undergoing a defrost cycle.
FIX: Normal operation.
CODE: t - Test Mod.
RESULT: Test Mod.
FIX: The ICC is in TEST mode.
RESULT: Test Mod.
FIX: The ICC is in TEST mode.
CODE: P - Protector Trip.
RESULT: A command for compressor operation is present but no current is measured to the compressor.
FIX: Motor protector open.
RESULT: A command for compressor operation is present but no current is measured to the compressor.
FIX: Motor protector open.
CODE: 01 - Long Run Time (Compressor).
RESULT: The compressor has continuously run for more than 18 hours in the cooling mode.
FIX: Low refrigerant charge. Air ducts have substantial leakage. Dirty indoor air filter. Dirty outdoor coil.
RESULT: The compressor has continuously run for more than 18 hours in the cooling mode.
FIX: Low refrigerant charge. Air ducts have substantial leakage. Dirty indoor air filter. Dirty outdoor coil.
CODE: 02 - High Pressure.
RESULT: Compressor limit has opened four (4) times within a call for operation.
FIX: Outdoor coil is dirty (cooling mode). Outdoor fan is not running (cooling mode). Dirty indoor coil or filter (heating mode). Indoor blower is not running (heating mode). Liquid line restriction. Excessive refrigerant charge.
RESULT: Compressor limit has opened four (4) times within a call for operation.
FIX: Outdoor coil is dirty (cooling mode). Outdoor fan is not running (cooling mode). Dirty indoor coil or filter (heating mode). Indoor blower is not running (heating mode). Liquid line restriction. Excessive refrigerant charge.
CODE: 03 - Short Cycling.
RESULT: ICC detects the run time for the past four (4) compressor or cycles is less than three (3) minutes each .
FIX: Check thermostat wire connection. Check thermostat location in zone..
RESULT: ICC detects the run time for the past four (4) compressor or cycles is less than three (3) minutes each .
FIX: Check thermostat wire connection. Check thermostat location in zone..
CODE: L4 - Locked Rotor.
RESULT: The ICC detects four (4) consecutive protector trips have occurred and the average run time for each trip is less than 15 seconds.
FIX: Bad run capacitor. Low line voltage. Excessive refrigerant in compressor. Seized bearings in compressor.
RESULT: The ICC detects four (4) consecutive protector trips have occurred and the average run time for each trip is less than 15 seconds.
FIX: Bad run capacitor. Low line voltage. Excessive refrigerant in compressor. Seized bearings in compressor.
CODE: 05 - Open circuit (Compressor Will not Run).
RESULT: The ICC has had a protector trip for longer than 4 hours.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity. Check for open compressor internal protector.
RESULT: The ICC has had a protector trip for longer than 4 hours.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity. Check for open compressor internal protector.
CODE: 06 - Compressor Open Start Circuit.
RESULT: The ICC detects current in the Run circuit but not in the Start circuit of the compressor.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
RESULT: The ICC detects current in the Run circuit but not in the Start circuit of the compressor.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
CODE: L6 - Compressor Open Start Circuit.
RESULT: The ICC detects current in the Run circuit but not in the Start circuit of the compressor four (4) times in one compressor call.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
RESULT: The ICC detects current in the Run circuit but not in the Start circuit of the compressor four (4) times in one compressor call.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
CODE: 07 - Compressor Open Run Circuit.
RESULT: The ICC detects current in the Start circuit but not in the Run circuit of the compressor.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
RESULT: The ICC detects current in the Start circuit but not in the Run circuit of the compressor.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
CODE: L7 - Compressor Open Run Circuit.
RESULT: The ICC detects current in the Start circuit but not in the Run circuit of the compressor four (4) times in one compressor call.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
RESULT: The ICC detects current in the Start circuit but not in the Run circuit of the compressor four (4) times in one compressor call.
FIX: Check for damaged, miswired, or wrong run capacitor. Check for broken Wires, loose connectors, or miswired compressor. Check compressor windings for continuity.
CODE: 09 - Low Secondary Volts.
RESULT: The secondary voltage at R and C is below 18VAC.
FIX: Control transformer overloaded. Low line voltage.
RESULT: The secondary voltage at R and C is below 18VAC.
FIX: Control transformer overloaded. Low line voltage.
CODE: 21 - Low Pressure Control Open.
RESULT: The ICC detects the LPC is open. Note: The low pressure control is ignored for the first 90 seconds of compressor operation .
FIX: Unit has low refrigerant charge. Indoor coil is frozen (cooling mode). Dirty indoor coil or filter (cooling mode). Indoor blower is not running (cooling mode). Outdoor coil is frozen (heating mode). Expansion valve is not operating correctly.
RESULT: The ICC detects the LPC is open. Note: The low pressure control is ignored for the first 90 seconds of compressor operation .
FIX: Unit has low refrigerant charge. Indoor coil is frozen (cooling mode). Dirty indoor coil or filter (cooling mode). Indoor blower is not running (cooling mode). Outdoor coil is frozen (heating mode). Expansion valve is not operating correctly.
CODE: L21 Flashing.
RESULT: Active Protection, Low Pressure Control Trip.
FIX: LPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 21.
RESULT: Active Protection, Low Pressure Control Trip.
FIX: LPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 21.
CODE: 27.
RESULT: Low Line Voltage or No Line Voltage Fault.
FIX: Check incoming line voltage to the disconnect and unit. Check wiring connections.
RESULT: Low Line Voltage or No Line Voltage Fault.
FIX: Check incoming line voltage to the disconnect and unit. Check wiring connections.
CODE: 28.
RESULT: High Line Voltage Fault.
FIX: Check line voltage.
RESULT: High Line Voltage Fault.
FIX: Check line voltage.
CODE: 29.
RESULT: High Pressure Control Open. The ICC detects the HPC is open.
FIX: Outdoor coil is dirty (cooling mode). Outdoor fan is not running (cooling mode). Dirty indoor coil or filter (heating mode). Indoor blower is not running (heating mode). Liquid line restriction. Excessive refrigerant charge.
RESULT: High Pressure Control Open. The ICC detects the HPC is open.
FIX: Outdoor coil is dirty (cooling mode). Outdoor fan is not running (cooling mode). Dirty indoor coil or filter (heating mode). Indoor blower is not running (heating mode). Liquid line restriction. Excessive refrigerant charge.
CODE: L29 Flashing - Active Protection.
RESULT: High Pressure Control Trip.
FIX: LPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 29.
RESULT: High Pressure Control Trip.
FIX: LPC has opened 3 times in the same cooling operation, the ICC has locked out the compressor to protect it. ICC alternately flashes L and 29.
CODE: 30 - Fuse Open.
RESULT: The ICC detects the on-board fuse is open.
FIX: The 3 amp fuse on the ICC is open. Low voltage Wiring at R and C is damaged or miswired.
RESULT: The ICC detects the on-board fuse is open.
FIX: The 3 amp fuse on the ICC is open. Low voltage Wiring at R and C is damaged or miswired.
CODE: 80 - Low Air Flow.
RESULT: The ICC detects that the indoor unit is not providing the minimum airflow requirements.
FIX: Misappliedwrong indoor air mover - replace With properly sized unit.
RESULT: The ICC detects that the indoor unit is not providing the minimum airflow requirements.
FIX: Misappliedwrong indoor air mover - replace With properly sized unit.
CODE: 83 - Condenser Coil Temperature Fault.
RESULT: The sensor detects an abnormally low or high coil temperature.
FIX: Replace the sensor. Check sensor is installed correctly on control.
RESULT: The sensor detects an abnormally low or high coil temperature.
FIX: Replace the sensor. Check sensor is installed correctly on control.
CODE: 84 - Outdoor Ambient Temperature Fault.
RESULT: The sensor detects an abnormally low or high outdoor ambient temperature.
FIX: Check unit placement - If the outdoor unit is in a high temperature area, wait until the ambient temperature drops and check sensor reading. Replace the sensor. Check sensor is installed correctly on control.
RESULT: The sensor detects an abnormally low or high outdoor ambient temperature.
FIX: Check unit placement - If the outdoor unit is in a high temperature area, wait until the ambient temperature drops and check sensor reading. Replace the sensor. Check sensor is installed correctly on control.
CODE: 93 - Internal Control Fault.
RESULT: The control is not functioning properly.
FIX: Check control for proper system Operation. Replace control.
RESULT: The control is not functioning properly.
FIX: Check control for proper system Operation. Replace control.
CODE: d1.
RESULT: N0 Shared Data.
FIX: Replace memory card With correct system information.
RESULT: N0 Shared Data.
FIX: Replace memory card With correct system information.
CODE: d3 - Airflow CFM Mismatch.
RESULT: The indoor air mover (air handler/furnace) cannot supply the required airflow for proper system operation.
FIX: Misappliedwrong indoor air mover-replace With properly sized air handler/furnace.
RESULT: The indoor air mover (air handler/furnace) cannot supply the required airflow for proper system operation.
FIX: Misappliedwrong indoor air mover-replace With properly sized air handler/furnace.
CODE: d4 - (Device) Memory Card Invalid for Device.
RESULT: The data in the memory card inserted into the control board does not match the data in the control.
FIX: Check memory card to ensure it matches device. Check if memory card is present.
RESULT: The data in the memory card inserted into the control board does not match the data in the control.
FIX: Check memory card to ensure it matches device. Check if memory card is present.
CODE: d8 - Old Shared Data.
RESULT: System data is obsolete.
FIX: If system Will not operate, order new memory card to update system information.
RESULT: System data is obsolete.
FIX: If system Will not operate, order new memory card to update system information.
See What Our Customers Are Saying:
Sep 3, 2022
We contacted TwinTech after having another ductless air-conditioning company come in to quote on a solution for our townhouse. We had a unique problem where my office was a hot spot - it's at the front of the unit and gets a lot of sun. If it's 20C outside, It's 29C in my office. The other company could not build a solution that would get a ductless unit to that room because of the location - the AC unit would have to be at the rear, and ductless systems would have to be on that side of the interior. TwinTech suggested a hybrid solution to fit our unique problem, where the ductless unit would move cold air to an air exchanger installed in our bedroom closet, and then they built a ducted vent system between all the upper rooms. This was less intrusive than building a central air system, and less expensive. Each room has a vent that I can close off, so I can push more cold air to my office when needed. We really didn't want ductless units sitting on the walls, and this looks and works better. I really appreciate the extra thought and care that went into the design of a solution, and the attention to detail in the installation. They answered all of our questions, and were able to do a bit extra by installing the ducts around the vents and painting them for us. It cost more than we originally planned for, due to our unique needs, but the fact that they offered financing helped us budget for more.
The job was done fast (I think we got lucky with timing where it wasn't the AC install busy season yet), and the team was very friendly and professional. They arrived and finished each day when they said they would. My office is now running at a comfortable temperature! I'm extremely happy with the experience and would whole heartedly recommend them.
Sep 2, 2022
How lucky are we to have this team come save us from our broken down, under sold, poorly installed previous unit (mind you there is a reason SEARS went bankrupt). Bob arrived on time to give us a detailed review of our unit and furnace; very knowledgeable. Greg arrived as planned with the new unit and reiterated what Bob explained how our furnace is equipped to handle the new unit and we didnt need to spend more money on a variable speed air conditioner. Cant say enough on how professional, efficient and personable this team is. Thank you so much guys!
Sep 1, 2022
We used Twintech for our replacement AC. Bob did a great job assessing what we needed and organized the install and showed up on install date. Greg and Mitch were on time and were very neat. They covered the traffic areas with a drop cloth and did an excellent install. Great clean up after install complete. Would recommend Twintech for heating and cooling.
Aug 31, 2022
They were fantastic, clean, freindly, great service. Would definitely recommend. Answered ally questions and more.
Aug 30, 2022
We woke up at about 7 a.m. the Sunday morning before Valentine's Day to a house that was barely 15 degrees Celsius on a really cold day. We tried to call some other suppliers but no answer or call back. We did a quick google search and Twintech came up. Had never dealt with them before. They had a chat line and lo & behold, someone answered; Greg. Helped us diagnose that our 40 year old furnace pilot light was out and walked us through how to relight it. All worked well; he even called me during this process. No charge I was told when asked.
15 minutes later, the pilot went out. It would not stay lit. Greg had Bob call us and we set up a meeting for about 11 a.m. that same Sunday.
Bob walked us through the options and even brought 3 electric space heaters for us to use. By Tuesday afternoon, we had a new Furnace and central air installed.
The team was helpful, responsive and respectful. Very glad we found them by accident and looking forward to a nice cool summer after a warm winter.
Thanks guys!
Aug 29, 2022
Dealing with Bob and the installation crew was a pleasure. They took the time to explain everything. What would benefit us the most and the price difference. They were in and out in a reasonable time frame and fit us in within a couple days of original meeting. Quality of work is excellent as well.
Aug 28, 2022
A pleasure dealing with Bob ,Spencer and Mitch . They are professional and they also observe the covid 19 precautions . Bob explained the whole process and got the new furnace up the next day . Highly recommend
Aug 27, 2022
Would like to thank TwinTech for their quick response to our furnace repair. We used TwinTech to install a new furnace and AC a few years
back. Our furnace started to have problems early in the evening of extremely cold night. Contacted TwinTech and they were able make a service call later that evening. They got the furnace going and came the next day to replace a part. The part was under warranty and there was
no charge for either service call!
We are extremely happy with their customer service and would highly recommend them.
Gary & Kelly
Aug 26, 2022
This is the second time we have had Twintech to our house. A couple of summers ago they were in for an issue with our air conditioning. This time it was our furnace having an issue. It was shutting off randomly and not coming back on. Greg came right away and took the time to investigate thoroughly and explain what was going with the furnace. Both times I have been thoroughly impressed with their speed, customer service, and quality of work. I HIGHLY recommend Twintech.
Aug 24, 2022
Extremely happy.
So we were in no rush to replace our old units and took the time to do some research and get a number of quotes.
Twintech came in at around the middle of the pack for price but what convinced us to go with them was Bob, the representative that came to our house. Bob was by far the most professional of all the reps that we met with. He took the time to explain everything, what would work best for us and why. He really did seem very knowledgeable and enthusiastic about his stuff.
As promised on the day of install the crew showed up on time and got to work with minimal impact on us
..they were professional, clean, tidy and got the system up and running ahead of schedule...they made a couple of adjustments to the system to optimize it for our house.
The crew left the house clean and tidy.
Bob the rep showed up to check in and give us a few tips ..
It's been a week since install and all is good.
Our overall experience with Twintech has been excellent from start to finish and I wouldn't hesitate to recommend them.
Thank u.
See What Our Customers Are Saying:
Feb 18, 2025
Very pleased with the professional service that TwinTech Heating and Cooling provided in replacing my furnace. I got several quotes from different service providers. Their price was excellent and they explained the features very well. We are very glad we went with TwinTech and highly recommend their services.
Feb 18, 2025
We were new homeowners in need of a second opinion. TwinTech Heating & Cooling were Amazing and professional. Very knowledgeable and great service all around. Recommend to anyone looking for honest and reliable services. Treated with respect and care. Thank you Greg, Mitch and Bob!
Feb 18, 2025
TwinTech is an excellent and honest company! I called them for a second opinion after being told by another company that I needed to replace my furnace. Turns out this was not the case at all! I did not need a new furnace. TwinTech did not push to make an unnecessary sale and saved me from a huge expense. Bob and Mitch were extremely professional and above all honest! I definitely recommend TwinTech!
Feb 18, 2025
Amazing experience with TwinTech Heating & Cooling! Their team was professional, knowledgeable, and efficient from start to finish. They installed my new furnace quickly and left everything spotless. The technicians took the time to explain everything and made sure I was comfortable with the system before they left. Great customer service and fair pricing. I highly recommend them for anyone needing HVAC services!
Feb 18, 2025
Great experience all around. Bob was sharp and easy to talk to, and Greg handled the installation perfectly. Would hire them again in a heartbeat.
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