Durham Region Air Conditioning Repair, Service and Installation
With this A/C troubleshooting guide, you can find problems with your system, fix it yourself. We will guide you through the process of identifying the problem and repairing your air conditioner.
Fault Display on the Dual 8 Numeral Tube of Outdoor Mainboard
CODE: E1.
RESULT: Actuation of high pressure switch.
FIX: Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
RESULT: Actuation of high pressure switch.
FIX: Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
CODE: E3.
RESULT: Actuation of low pressure switch.
FIX: When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than 3sec and the system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
RESULT: Actuation of low pressure switch.
FIX: When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than 3sec and the system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
CODE: E4.
RESULT: Air discharge high temperature protection of compressor.
FIX: The exhaust temperature is higher than 125C for more than 5sec, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90C for more than 5 sec, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
RESULT: Air discharge high temperature protection of compressor.
FIX: The exhaust temperature is higher than 125C for more than 5sec, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90C for more than 5 sec, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
CODE: F2.
RESULT: Malfunction of condenser temperature thermistor.
FIX: Malfunction of condenser temperature thermistor is detected when there is a short circuit or an open circuit in the condenser temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.
RESULT: Malfunction of condenser temperature thermistor.
FIX: Malfunction of condenser temperature thermistor is detected when there is a short circuit or an open circuit in the condenser temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.
CODE: F3.
RESULT: Malfunction of outdoor ambient temperature thermistor.
FIX: Malfunction outdoor ambient temperature thermistor is detected when there is a short circuit or an open circuit in the outdoor ambient temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.
RESULT: Malfunction of outdoor ambient temperature thermistor.
FIX: Malfunction outdoor ambient temperature thermistor is detected when there is a short circuit or an open circuit in the outdoor ambient temperature thermistor for more than 5 sec. The system will be shut down. The reset for the malfunction of condenser temperature thermistor is automatic.
CODE: F4.
RESULT: Malfunction of Exhaust Temp. Sensor.
FIX: If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 2 minutes or short circuit 5 seconds successively at any time .The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.
RESULT: Malfunction of Exhaust Temp. Sensor.
FIX: If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 2 minutes or short circuit 5 seconds successively at any time .The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.
CODE: ON.
RESULT: Normal operation.
FIX: Unit operating normally or in standby mode.
RESULT: Normal operation.
FIX: Unit operating normally or in standby mode.
CODE: H1.
RESULT: Defrost operation.
FIX 1: Power problem. Check control transformer power (24V). If power is available to demand control board and LED(s) do not light, replace control board.
FIX 2: Actuation of high pressure switch. Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 3: Actuation of low pressure switch. When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than3sec and the system will be shut down..The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 4: Air discharge high-temperature protection of compressor. The exhaust temperature is higher than 125C for more than 5s, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90C for more than 5s, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 5: Malfunction of exhaust Temp. Sensor. If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 3 minutes or short circuit 5 seconds successively at any time The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.
RESULT: Defrost operation.
FIX 1: Power problem. Check control transformer power (24V). If power is available to demand control board and LED(s) do not light, replace control board.
FIX 2: Actuation of high pressure switch. Abnormality is detected when the contact of the high pressure switch opens for 3 sec. The system will be shut down. The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 3: Actuation of low pressure switch. When the unit runs more than 4 minutes or does not run, the low pressure switch opens for more than3sec and the system will be shut down..The unit will report this fault. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 4: Air discharge high-temperature protection of compressor. The exhaust temperature is higher than 125C for more than 5s, the system will be shut down. After stopping the compressor for 3 mins, if the exhaust temperature is lower than 90C for more than 5s, the compressor will re-start. For the first two faults within 30 minutes, the unit can be recovered automatically. If over three times, the unit cannot be recovered automatically.
FIX 5: Malfunction of exhaust Temp. Sensor. If the exhaust temperature sensor is detected of open circuit 5 seconds successively after the compressor is started for 3 minutes or short circuit 5 seconds successively at any time The system will be shut down. After the fault is eliminated, the system can automatically resume to operation.
See What Our Customers Are Saying:
May 9, 2018
I had cold and hot spots all over my 70 yr old home. My furnace is quite new and Greg optimized the fan and furnace. The original installer just took it out of the box with factory settings and installed it- basically running at 50% of capacity. Greg also routed heat into my laundry room, yeah - so now I can renovate laundry room - thanks Greg. He is honest, professional and knowledgeable. I will be calling him back in the spring to optimize my AC as well.
May 8, 2018
Wonderful from beginning to end. I tend to fret and worry about home improvements but the excellent team at TwinTech put my mind as ease. They listen, they are patient and best of all ... the work they did is amazing! I chose the Goodman 80K BTU 2 stage furnace and the matching Goodman air conditioner. Greg, Grant and Poitr "Peter" arrived on time, took great care, explained everything to me and they answered all of my questions. They carefully adjusted the factory settings to optimize the furnace for my house and they also checked the duct work in the basement. Dave, the Sales Manager, came by to say "hello" and to see if I was happy. YES, I am happy with the work! The furnace is very quiet. I have it running on low just to circulate the air in the house and it's so much quieter than my old furnace. When I need new duct work for an upcoming basement renovation TwinTech will be my first choice. I highly recommend TwinTech. PS. They were even nice to my dogs.
Apr 21, 2018
Greg was prompt on the scheduled day of installation and the work was done well within the time estimated beforehand. Installation was neat and the equipment and scope of work was as specified in the quote. One item I must point out is that we were faced with a "No Heat" situation the day before the scheduled installation and Greg came out to address it free of charge. Not only that, but he also corrected an installation fault with our smart thermostat that was not part of the original job, again free of charge.
Mar 16, 2018
Greg came by to do a routine furnace checkup. He was very knowledgeable and professional, letting me know what's being checked/adjusted and giving me tips to ensure everything runs smooth. Very honest and upfront about what's working fine vs. what may need to be fixed/replaced. He didn't attempt to up sell anything that wasn't necessary. I'm glad to have finally found someone I can trust and rely on for all my HVAC needs - furnace, A/C, and hot water tank.
Mar 4, 2018
I'm very happy with the work that was done. Everyone from salesperson to the installers were friendly and professional. They were on time and cleaned up the job site after it was installed. They also answered all my follow up questions promptly. I wouldn't hesitate to work with them or recommend them again.
Feb 28, 2018
Thanks to the team at Twin Tech for a great job installing my new heat pump/ac unit. The guys were very polite and professional. When they left you would never have known they had been there except for the new Mitsubishi unit on the wall!! would highly recommend the Twin Tech team.
Feb 28, 2018
Installed professionally, no delays, no rework needed. Very reliable contractor and sales person. Also installed BBQ gas line and some duct work.
Feb 19, 2018
Greg and Grant are friendly, reliable, and knowledgeable HVAC professionals. The twins, Dave and the entire team provided efficient top quality service. Our family plns to use Twintech for all of our future HVAC needs.
Feb 10, 2018
Very impressed with this company. They show up on time , kept my place clean and after they left it looks like they were never there. Very professional team. Those people know what they doing . Their installation was on the highest standard. They are very knowledgeable especially they're worker Peter. I strongly recommend this company to everybody. After the installation I receive the call making sure I'm satisfied with their products and their job. Bravo!!!
Feb 8, 2018
Greg and his brother were referred to us by a friend. They arrived when they said they would, did an exceptional job and left the place as tidy or tidier then they found it. Their professionalism is only surpassed by their kind and friendly demeanor. Even after several calls to help me with my high tech thermostat I feel that I could always call with any concern (No one responds to my texts as quickly as Greg) and have a friendly helpful response. I found out their grandfather started the company and now as a 3rd generation company, they are doing their grandfather proud. I would highly recommend Twintech over any other hvac company out there.
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.
My Furnace Unit Makes Strange Noises
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - October 14, 2024
If your furnace unit is making strange noises, it could indicate a variety of underlying issues that require attention. Here's a breakdown of common furnace sounds and what they might mean: Banging or Popping: This could be caused by exp
Read MoreOne System for Both Heating and Cooling
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - July 10, 2025
When it comes to keeping your home comfortable year-round, most homeowners rely on two separate systems: a furnace or boiler for heating in the winter, and an air conditioner for cooling in the summer. But what if you could have a single, energy-e
Read MoreWhy Heat Pumps Are a Better HVAC Choice
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - May 8, 2025
When it comes to heating and cooling your home efficiently, the debate between heat pumps and traditional air conditioners is becoming more relevant than ever. While both systems can provide cooling, heat pumps offer several advantages that make t
Read MoreDetriments of an Old AC Unit
- SUBMITTED BY:
- TWINTECH HEATING & COOLING
- - May 13, 2024
There are several drawbacks to having an old or outdated air conditioning (AC) unit: Reduced Efficiency: Older AC units tend to be less energy-efficient than newer models. They may consume more electricity to produce the same level of coolin
Read More