$49 / month O.A.C Including Install
$49 / month O.A.C Including Install

24 / 7 Emergency Service Available. Call Us Now: 1.844.894.6832

Durham Region Air Conditioning Repair, Service and Installation

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The flashing LEDs on your furnace will correspond to a specific fault code that is shown here on their diagnostic chart.


International Comfort Products Corporation (ICP) is a company that designs, manufactures and markets central air conditioning (HVAC) systems and gas and oil furnaces for use in homes and commercial buildings. It is a unit of Carrier Global Corporation and is headquartered in Lewisburg, Tennessee, United States.


CODE: LED Off
RESULT: 24 VAC or 115 VAC is off, fuse is open.
FIX: Check whether the door switch isn't closed or for a short circuit.

CODE: LED On
RESULT: Soft lockout, furnace control error, 1 hour delay. If code repeats immediately following power reset, then replace control.
FIX: Will auto-reset after 1 hour.

CODE: Heartbeat
RESULT: Normal operation.
FIX: N/A.

CODE: 2 Flashes
RESULT: Pressure switch closed when should be open.
FIX: Check for an obstruction in the pressure tubing.

CODE: 3 Flashes
RESULT: Pressure switch open when should be closed on single stage models. Low pressure switch open when should be closed on 2 stage.
FIX: Check for: excessive wind; proper vent size; defective inducer motor; defective pressure switch; inadequate combustion air supply; disconnected or obstructed pressure tubing; or restricted vent.

CODE: 4 Flashes
RESULT: Limit switch or rollout open.
FIX: Check for: restricted vent; proper vent sizing; loose blower wheel; excessive wind; dirty air filter; or defective blower.

CODE: 5 Flashes
RESULT: Flame sensed out of sequence.
FIX: Check for a leaky gas valve or a gas valve that is stuck open.

CODE: 6 Flashes
RESULT: Failure to ignite or flame sense lost while running.
FIX: Check for: an ungrounded flame sensor; defective hot surface ignitor; low inlet gas pressure; oxide buildup; manual valve shut off; control ground continuity; inadequate flame carryover; or rough ignition.

CODE: 6 + 1 Flashes
RESULT: Soft lockout - Max of 4 trials for ignition reached (3 hour delay).
FIX: Control will auto-reset after 3 hours.

CODE: 7 Flashes
RESULT: Soft lockout - Limit of roll-out switch open longer than 2 minutes (1 hr delay)(rollout switch requires manual reset).
FIX: A lockout will occur if the limit or flame rollout is open for longer than 3 minutes. Control will auto-reset after 3 hours.

CODE: 8 Flashes
RESULT: Permanent lockout - Gas valve relay contact stuck closed or mis-wired gas valve (power reset only).
FIX: Check for a miswired gas valve or a defective control valve.

CODE: 10 Flashes
RESULT: Line voltage polarity reversed. If twinned, refer to kit instructions.
FIX: Review instructions to correct polarity.


See What Our Customers Are Saying:

by Aileen Johnson in Toronto on Twintech Heating and Cooling

All staff concerned were total professionals. Sales rep Dave was like having an old friend at your house. No up selling or pressure, just good honest facts and figures. The owners and assistant who installed our unit worked quietly, efficiently and left our home clean. We could not have been happier with the service and attention we were given. We are so happy a family member recommended Twintech. She said "don't call anyone else, just call them...they are amazing". And they were!!! Thank you guys for the great work!!! A. Johnson

by Lynsey from Toronto on Twintech Heating and Cooling

We are completing a large project adding an addition on to our house and couldn’t be more pleased with our decision to trust Twintech with our hvac work. They removed and replaced the furnace, installed a new A/C unit, swapped our tank water heater for a tankless unit, and completed ducting and new A/C lines through the addition. Without hesitation we would recommend Twintech to anyone.

by Oldtown in Pickering on Twintech Heating and Cooling

Honest, very personable , men of their word ,workmanship xcellent ,showed up when promised ,They do not try to up sell ,rather give good advice instead . Price was very fair in my opinion .We have a family member with a medical condition and I think they made us a priority .Very happy with these guys . (Nice guys ) Stu Leffler Ajax.

by Mike B. Toronto on Twintech Heating and Cooling

Very professional, courteous, knowledgeable staff. Sales staff (David Gergley) excellent in knowledge and getting the job setup and installation was very prompt. Greg and Peter (technicians) knew their stuff and stuck around after completion to make sure it all worked properly and that I understood how it all was installed and how the unit worked. Would highly recommend them! Thanks for a great job-house is now cool and comfortable.

by Steve S in Toronto on Twintech Heating and Cooling

I had Twintech install a brand new air condition back in June of this year and I'm very happy with their service. I have a very busy schedule so I sent out an email to 7 or 8 HVAC companies just to get an idea of what it would cost. Dave at Twintech and only one other company were able to give me an approximate quote through email. Many of the companies I reached out to didn't even respond. I decided to meet with Dave and he was very friendly and professional. He gave me a good quote for a name brand/energy efficient AC with installation from their certified technicians. It was an easy decision to go with them.

Within a week I had the unit installed and working perfectly. Their technicians were very helpful and answered all of my questions. I'll definitely be calling them back for all of my HVAC needs in the future.

by Tina - Whitby in Whitby on Twintech Heating and Cooling

The people from Twintech were very friendly and personable...from the salesman to the installers. The installation was done as scheduled. I love my new air conditioner. My neighbour has a York and that thing is so noisy compared to my Goodman!! Thanks Twintech!!

by Cathy f. from Pickering on Twintech Heating and Cooling

Thank you, Twintech. They installed an A/C in my home in the middle of a heat wave which we appreciated very much. I found the team good, not overly friendly, other than the brothers. Dave, the salesperson was awesome, and, it's because of him that I was sold on using Twintech. I had other questions about additional work I am curious about and would have liked them to follow up and provide a quote. Other than that, which ultimately is not related to the great work they did, I would definitely recommend them, although I don't believe they go outside of Durham (check with them).

by Linda from Durham Region on Twintech Heating and Cooling

We have used this company a few times so I can't remember exactly what we paid but I do know that their fees are always very reasonable.

The first time we called Greg was when our furnace conked out while we were away. He came right away, showed me the problem and fixed it immediately.

The second time was when we needed an air conditioner moved and lifted to a platform. Again, he showed up on time, completed the job quickly (including a new gas line) and the fee was very reasonable.

We have received a quote from Greg to replace the air conditioner and furnace and when we are ready to move ahead, we will be calling him.

I have no hesitation in recommending TwinTech!

by AS from Pickering on Twintech Heating and Cooling

Our rating for Twintech is 5/5 stars. They are very professional and efficient, and the transparency they maintain right from the preliminary assessment till the day of the work is a testament to their experience in the field. We had Twintech replace our air conditioning and furnace, and we appreciate the efforts taken by Greg.

by Raymond from Toronto on Twintech Heating and Cooling

After 18 years my Air conditioner died in the middle of a heat wave. I entered my information on Home Stars and within the hour Dave from Twin Tech responded and offered to meet me as soon as possible depending on my availability. Dave was very knowledgeable about the products Twin Tech offered and even though this was the first quote I received . I felt very comfortable in giving Twin Tech my business. maybe it was the professional approach. Needless to say that the crew with Greg and Grant arrived promptly at the time they committed to were very professional and within a few hours had the place cool. They cleaned up and one would never know that I had work done . I know that the System is new and I probably wont need to worry about it for some time. However with the professionalism displayed by the crew I feel assured that should I need to call for service Twin Tech will respond. I also know that should I need a new Heating system I will go with Twin Tech. Keep up the good work.

See What Our Customers Are Saying:

by Aaron on Twintech Heating and Cooling

We are very happy to recommend this company to everyone. Our furnace broke down on Sunday morning. We phoned them and before noon Grant the owner showed up. He worked on the furnace for about a hour not wanting to give up to fix the problem. The furnace was 17 years old. I was the one talking about replacing it. End result was the next day it was all done. On the Sunday Bob came over with heaters to warm up the house. We decided to replace the water heater at the same time. Thanks Grant for the excellent work. Thumbs up.

by Linda on Twintech Heating and Cooling

Right on time. Explained how to work the HRV in a different way so the house would not be so dry. Changed my whole house water filter for me as well. Friendly, helpful, caring service!

by Robert Rogers on Twintech Heating and Cooling

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.

by Robert Mizuno on Twintech Heating and Cooling

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!

by Ruth on Twintech Heating and Cooling

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!

Quick Troubleshooting Guide for Furnace Issues

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - December 9, 2024

A malfunctioning furnace can be a major inconvenience, especially during colder months. Below is a simple guide to help identify and potentially resolve common furnace issues before calling a professional. 1. Furnace Won’t Turn On Ch

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What Parts of My AC Can Be Replaced?

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - April 8, 2024

In an air conditioning system, various components can be replaced depending on the type of issue you're experiencing or the maintenance required. Here are some common parts that can be replaced in an AC system: Air Filters: These should

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Will Cleaning My AC Effect Its Performance?

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - May 19, 2024

Yes, cleaning your air conditioner (AC) can significantly affect its performance in several positive ways: Improved Efficiency: Dust and debris can accumulate on the AC's filters, coils, and fins, obstructing airflow and reducing the sys

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Twintech - Your Experts on Heat Pump Rebates in Oshawa

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - August 19, 2025

If you live in the Durham Region or Toronto and are considering upgrading your home’s comfort system, now is the perfect time. With generous rebates available on Amana and Panasonic heat pumps, homeowners can save thousands while enjoying ef

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