--- title: "How Often Should I Service My Propane Heater to Keep Efficiency High?" description: "More of your real questions, answered by an HVAC technician with over 10 years of experience." date: "2024-11-13" modified: "2024-11-13" authors: - name: "BobVila.com Staff" link: "https://www.bobvila.com/authors/bob-vila-staff.md" url: "https://www.bobvila.com/interior/ask-a-pro-home-heating-propane-heater-efficiency/" categories: - "Heating" - "Heating & Cooling" - "Interior" tags: - "DIY" - "News" --- # How Often Should I Service My Propane Heater to Keep Efficiency High? ![HVAC Technician Checking Units Outside House]() *Photo: istockphoto.com* Welcome to Ask a Pro! We take your questions about home improvement, DIY, lawn and garden, and homeownership and answer them with the help of professionals. Our experts are vetted and verified—and they’re eager to share their knowledge. Last month, BobVila.com readers submitted home heating questions on Facebook and Instagram, and via our newsletter. We hand-picked our favorites, and tapped Micah Sherman of [Frontdoor]() to help answer them. In this installment of our Ask a Pro series, Micah tackles your questions about your home heating issues. He'll also be joining us for our [Ask a Pro LIVE webinar event about home heating for less money](). ## I have water that runs down the backside of my furnace blower, pooling below it. HVAC guys can't find the problem, I believe it's the manifold between the heat exchangers. How do you check that? —Jeremiah, via Facebook **Micah's advice:** It sounds like your secondary heat exchanger has failed. As the combustion gasses cool off in the secondary heat exchanger, they produce acid. The secondary heat exchanger has a protective coating applied to it, but eventually, it will fail. Once the coating is gone, the acids eat away at the metals of the heat exchanger, causing them to decompose, rust, and eventually plug and produce pin hole leaks. So, what you are seeing in this scenario is that the water is collecting at a point in the secondary heat exchanger where the protective coating is gone, and the acid has eaten away the metal. This seems to have produced a pin hole leak, which is where the water is leaking out. Over time, this pin-hole leak will continue to grow, which will produce more and more water. The only way to solve this problem is to replace your secondary heat exchanger. The best way to confirm this is to drill a small hole in the PVC exhaust. There you can use a CO monitor to test the parts per 1 million of CO in the exhaust fumes. Each manufacturer has a different scale on what they consider “failed’, but having the carbon monoxide tested is imperative for your safety. If the results are over the failure limit set by the manufacturer, then you know that the secondary heat exchanger has failed. https://www.youtube.com/shorts/EnAd8Zjh1Rg ## How often should I service my propane heater to keep efficiency high? —Jim, via Facebook **Micah's advice:** The best way to keep your propane heater efficient and working properly is to perform routine maintenance on it once a year. As it is usually best to service your heater before the heating season begins, I recommend having it serviced every fall—before you are ready to use it daily. If you have been having issues with your propane heater failing frequently, or you’ve noticed that it’s not as efficient as it used to be, this could be due to age or a lack of annual maintenance. ## When all my thermostats are turned off, should I still hear the HVAC fan? —Gina, via Facebook **Micah's advice:** No, if every thermostat in your home is set to “off” then the fan should not be running. However, note that depending on your system type, the fan can continue to run after the system has been turned off for a few minutes, which happens to maximize efficiency. After the unit turns off, there is still heat (or cold air in AC mode) inside the furnace. The blower will continue to run for a few minutes to push all of that air out of the system and into the home. If you’re still hearing the fan long after the system has been turned off, or the thermostat has been satisfied and the home is at the desired temperature, be sure to check and make sure that the fan itself is set to “auto” as opposed to “ON’ or “CIRC”, which will make the fan run continuously, regardless of whether or not the thermostat is calling for heat or AC. If the system is set to “off” and the fan to “auto” and you can still hear the fan running, this is a sign that something has malfunctioned, causing the fan to stay on indefinitely.