Heating Maintenance

If you live in northern Arizona you know how important maintaining your Furnace, heat pump or boiler can be. There are many reasons for heating maintenance. If you live in Flagstaff Arizona where it’s a higher altitude it’s very important to know that your gas appliance has the correct set of orifices’ in the manifold and that the gas valve that provides the fuel to be burned in the heat exchanger has been set correctly. If the orifices’ are not properly sized than you either are burning to rich a mixture of fuel to air which will soot up the entire heat exchanger tubes or clam shells thus eventually causing a back burn effect or complete shutdown of the system. The back burn effect is when the flames actually roll out of the burner area and start burning the wires that control the furnace. If this happens it usually is caught by circuit breaker sensing a short thus turning off power to the appliance. This can be a very expensive HVAC Repair because not only do you have to repair all the burned wires and control boards but most likely have to pull the entire furnace outside so that the heat exchanger tubes or clam shells can be completely cleaned. If the orifices’ are too small you can have a situation where the gas appliance (Furnace or Boiler) is running too hot. This can cause the heat exchanger to crack prematurely thus providing Carbon Monoxide to the occupants in the home while the appliance is operating. Both of these cinereous happen every day due to installers not having the right training to commission a job once it has been installed. Some of the time its due to a repair that was made maybe on an afterhours call and the technician  who made the repair was in a hurry and did not bother to double check his or her work before leaving the home. The quickest way to check the performance of the gas appliance is to check the temperature rise across the furnace. That is done by measuring the incoming temperature and comparing that temperature to the outgoing temperature. This gives the technician a good indicator of how the furnace is doing.


Most gas utility companies that serve the northern Arizona area such as Flagstaff, Sedona, Camp Verde and Cottonwood provide the incoming gas pressure and are only responsible for that portion. They do not make repairs to gas appliances but rather refer licensed HVAC Contractors to do that work. Maintaining the proper gas pressure to the appliance should also be part of a maintenance plan. It’s very easy for a trained technician to measure the incoming pressure that is provided by the gas utility company. If that pressure is not where it should be than the homeowner must call their local provider and have them check the incoming gas regulator and reset it if necessary. Another area that should be discussed is how the gas appliance vents its flue gases out of the home. Maintenance plan should include checking the vent system. Just like sizing the proper furnace for the home it’s very important that the gas appliance (Furnace or Boiler) vent system be sized and designed correctly or it will cause major performance issues to that appliance and to the occupants of the home. Venting issues usually are found out about fairly soon after the appliance has been run for a period of time. Rarely do venting issues come up years later unless the vent system had been blocked by an animal building a nest in the vent system or the vent system had collapsed due to someone working in the attic or crawl space where the vent system was installed.


You should always have your system checked for any carbon monoxide leaks from your furnace.  Most Carbon Monoxide detectors that you can buy off the store shelf have an audible alarm set for around 200 parts per million (PPM) This is when the occupant starts having mild headaches, nausea, fatigue and dizziness. HVAC contractors can use a meter that can measure any Carbon Monoxide coming from your forced air furnace so that if your furnace is starting to fail the contractor can ketch it before it causes major health issues.


Changing your furnace filter is the easiest and most recommended item that a home owner can do in order to provide great performance for the gas appliance. If the filter does not get changed on a routine basis than it can cause a long list of issues to the furnace and potentially early failure.
All of these maintenance items and a lot more are normally included in a comprehensive maintenance plan from your local licensed HVAC Contractor.

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