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

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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 Tracy, Pickering on Twintech Heating and Cooling

We couldn’t have been more impressed with Twintech - from our first service call with Mitch who took the time to thoroughly diagnose the issue with our furnace, to Dave who proposed a well thought out solution to meet our needs and finally Greg and team who acted quickly to install given we had no heat.


We did our due diligence by soliciting quotes from alternate providers and were shocked and disappointed by the aggressive and manipulative tactics used.


Twintech was honest in their approach, detailed in their product knowledge, reasonably priced, diligent in their follow-up and valued our business.


Well done Twintech! You made this a positive experience for us and our new furnace works beautifully!

by Skapoor, Ajax on Twintech Heating and Cooling

We recently purchased an Amana high efficiency furnace and humdifier through Twintech. The work was completed very professionally and the quality of the workmanship was high. There was some additional sheet metal work required to complete the installation, which they were able to complete themselves. Overall I am very pleased with the work and would highly recommend Twintech for a furnace replacement.

by Steve, Oshawa on Twintech Heating and Cooling

We were very pleased with every aspect of the work that was done. They were very professional and polite. They arrived when they said they would and job was completed on estimated time


We would highly recommend them to whoever needed a recommendation


We have a very large dog and they were very understanding and respectful of him being around

by Patrick, Toronto on Twintech Heating and Cooling

The blower on our furnace stopped working leaving us with a cold house. Dave from TwinTech responded immediately to our HomeStars service request. From beginning to end Dave was nothing but helpful, friendly and professional, he did a great job of walking us through the quote and scope of work.


The replacement of the furnace went smoothly. The Guys did a great job, everyone was very friendly and polite. There were no hiccups, or unexpected costs. The only surprise was they left the work area cleaner than it was before they started.


Was a great experience with the whole TwinTech team. Its been a couple of months since the new furnace has been installed and its working great!

by Ed, Whitby on Twintech Heating and Cooling

I heard about TwinTech when researching new furnaces at furnaceprices.ca. After contacting them about my broken down furnace, Dave came to my house the next day to assess my situation and requirements for a new furnace. He recommended one that had stainless steel heat exchangers which sold me since my previous furnace had issues with a rusted secondary heat exchanger that had to be replaced. Dave also set me up with an appointment with an energy audit company so that I could take advantage of a rebate to help improve the energy efficiency of my home and get some money back. A few days later, Greg, Grant, and Mitch came to install the new furnace and remove the old one. When delivering and removing the furnaces, they were very careful not to damage my floors and walls, and even laid out red carpeting to protect the floors. They were very friendly and professional. The installation was completed in the time they said it would take and they cleaned up their work areas. Within a week, Dave called to follow-up to see how everything was going. I have already recommended them to several friends and family members who may need new furnaces soon.

by Fred, Toronto on Twintech Heating and Cooling

Twintech did a great job, from Dave the Sales Rep to the Office staff and The Professional Technicians who did the installation. They were professional, courteous, knowledgable and informative. From beginning to follow up we were completely satisfied with everything. Thanks Again. Sincerely The Laytons

by Elle, Oshawa on Twintech Heating and Cooling

Great product, great service, great follow-up. The Twintech Heating and Cooling arranged removal of my existing oil tank and they installed the new gas furnace Amana (made in USA). I am very happy with the final result and support I received throughout the process. My thanks go to the entire Twintech team for their professionalism, great communication and follow-up.

by John & Linda, Ajax on Twintech Heating and Cooling

We've had Twintech provide us with work in the past, for an inground pool heater and required rough-in for a new gas stove. More recently they provided the same friendly, professional, timely and clean installation of our new furnace.

by Bill, Whitby on Twintech Heating and Cooling

Reasonable price and the workmanship was prompt and timely and the employees were great to deal with.

by Nadia, Toronto on Twintech Heating and Cooling

The sales process was friendly, informative, and very consultative. They worked hard to earn our business by taking a careful look around our home to assess our needs, providing a lot of information about the product, and answering all our questions and finding the right solution for our home at a competitive price. They prepared us very well for what to expect on installation day, and the installation went very smoothly - no surprises, all very professional! They gave us a call after installation to ensure we were happy with the work. We're very happy that we chose to work with TwinTech to get our new furnace.

See What Our Customers Are Saying:

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!

by Anna Chin on Twintech Heating and Cooling

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!

by Connor Agnew on Twintech Heating and Cooling

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.

Should I Get A Pool Heat Pump?

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - November 24, 2023

Whether or not you should get a pool heat pump depends on several factors, including your location, budget, and how frequently you use your pool. Here are some considerations to help you make an informed decision: Climate: Pool heat pumps wo

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Trying to find my holy grail of small AC units

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - September 28, 2023

My mom is getting on in years and is finally able to retire. She and my step-dad are moving to a beach house in a humid state and are hoping to keep their bedroom cool in the hotter months. Because of their general location, we're pretty ce

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Reducing Energy Costs on My AC

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - March 31, 2024

Reducing energy costs on your air conditioning (AC) system can help save money and reduce your carbon footprint. Here are several tips to achieve this: Use a Programmable Thermostat: Set your thermostat to higher temperatures when you're

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Whitby Furnace Cleaning

  • SUBMITTED BY:
  • TWINTECH HEATING & COOLING
  • - January 10, 2025

Regular furnace maintenance is essential for Whitby homeowners to ensure efficient operation, extend system lifespan, and maintain home comfort during Ontario's cold winters. Twintech Heating & Cooling, a trusted HVAC service provider in t

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