Finally, it is likely you have a dead short from what you are describing but let’s go through the basics first: What is the purpose of the fuse or breaker in a control circuit? Exact same problem. I replaced the transformer but the 3 amp fuse blows every time I change the thermostat to heat. Check each pair of wires that come up to the base. Finally, the re-settable breakers are especially good for troubleshooting problems such that you are describing. This could lead to overvoltages that could blow the fuse. I found that the transformer in the air handler is blown along with the 3amp fuse. This commission helps us pay for the overhead of running this website. If so, it will need to be replaced. Turn the thermostat to off and remove it from its base. 63.1k. If your air conditioning system is blowing fuses or causing your home’s electrical system to short out, contact the team at Air Experts Heating & Cooling. It is a Rheem criterion gas furnace. Yes, if you have a few extra fuses. Required fields are marked *. Join. This will determine wire size and transformer size. Any cookies that may not be particularly necessary for the website to function and is used specifically to collect user personal data via analytics, ads, other embedded contents are termed as non-necessary cookies. We'll assume you're ok with this, but you can opt-out if you wish. Helping You to Do It Yourself! I suspect a bad board but owner claims last guy replaced board. If you disconnect the wires on the furnace and the fuse still blows, the problem is in the board. Coronavirus Update: We care about your health and continue to service our customers safely. These cookies will be stored in your browser only with your consent. For a better experience, please enable JavaScript in your browser before proceeding. Posts; Latest Activity; Photos . Can you help? If the fuse is blown or the low-voltage breaker is tripped, as will generally be the case in a short, first replace the fuse, or, better yet, use a test breaker, like the Supco Pro Fuse (in place of the fuse while testing) to eliminate wasting fuses. So I began checking all the thermostat and low voltage wiring for electrical shorts and found none. Faulty Transformer. Re: 3 AMP fuse keeps blowing out on Carrier furnace Actually, COM is common ground. I have a Trane XC80/XL19i system with a W/R 50v61-507 control board on the furnace. I have a Tempstar Model NTC6100KFG1 gas furnace. It’s important to note that changing temperatures can make these wires expand and contract, which could be affecting whether or not the electrical … If it did blow, it meant the control board was bad. In regard to the transformer if it had an issue, since its "before" the fuse wouldn't it just burn out or trip the main breaker? An example of this would be a relay or contactor. JavaScript is disabled. Furthermore, I would remove all the control wires from the board. Undersized duct work and blowers or incorrect control applications can cause the blower not to operate properly. low voltage Fuse keeps blowing on unit disconnect thermostat wires still does it disconnect molex plug at board does not blow fuse. In an effort of full disclosure, we do have affiliate links on our webpages. 3 Amp Control Board Fuse Keeps Blowing. That typically determines the limitations of the circuit. Transformers are rated by there VA rating and you never want to exceed the VA rating on the transformer. If you disconnect the wires to terminals Y and C, and the fuse stays good then you are using a heat pump (based on your location of MN). I’ve seen many things cause fuses to blow and breakers to trip. the low voltage wires are clear of shorts, so I don't know what to do next and it's 15 - Answered by a verified HVAC Technician This video will show you how to isolate where the low voltage short is coming from. It's been off for a month or two as we've been changing seasons here. Transformer keeps blowing. Within a 1.5 secs after I push door switch in the 3 amp fuse blows. Posted by 3 years ago. Ohming out the LV wires rarely finds the problem but again it does some times. Your email address will not be published. Furthermore, when the fuse blows you will know which wire is causing the problem. So it gets cold in the house and I realize I have not heat. That is to say did you accidentally downsize when you replaced it? If the coil gets a dead short in it then there is your problem. I replaced the fuse to see if it would blow open again but it didn't. Members. Re: 3 AMP fuse keeps blowing out on Carrier furnace Actually, COM is common ground. Blowing Low Voltage Fuse Breaker Trip | Control Wiring Troubleshooting - I’ve got a 5 amp fuse that keeps popping on a circuit board. We offer a full range of heating and cooling services including 24/7 emergency repair service. Low voltage fuse blowing in furnace. checked continuity on all wires from molex plug to ground only the green ground wire shows continuity. new posts. by High Performance HVAC | Technical Reference | 0 comments. Created Dec 22, 2010. If the fuse is blown or the low-voltage breaker is tripped, as will generally be the case in a short, first replace the fuse, or, better yet, use a test breaker, like the Supco Pro Fuse (in place of the fuse while testing) to eliminate wasting fuses. Read More. initial sympton is a blown 5A low voltage (LV) fuse. A “blown fuse” can mean many different things–several of which have little to do with actual fuses. This category only includes cookies that ensures basic functionalities and security features of the website. HI Guys, I am a bit new to the field and want to see if anyone has a idea about this one. It is mandatory to procure user consent prior to running these cookies on your website. Heating, Ventilation, & Air Conditioning. AC works fine but as soon a I switch to heat the fuse blows. In this case, you should call an electrician. Second consider adding a fast acting fuse on the low voltage side that is smaller than the transformer current rating, that way you eat fuses instead of transformers while you troubleshoot. The line/low voltage is fine. this video shows what a low voltage fuse looks like in an air handler. Necessary cookies are absolutely essential for the website to function properly. Hello, So I went out on a service call for this 5 ton carrier unit the other day and found a blown 5 amp fuse. I am still popping fuses and reading over 24 volts. I've removed low voltage wires coming from thermostat and ac unit and I've removed the 9 pin connector for the 24 volt circuit within the furnace. Thanks again and please let me know if you have any other ideas. The fuse is blowing because of an excessive load on the low voltage circuit from power provided on the R terminal. 3A Fuse on Circuit Board Keeps Blowing - Carrier Weathermaker 8000. I am still popping fuses and reading over 24 volts. Collapse. If the fuse didn't blow, it meant the thermostat wire was shorting somewhere. I have just a cheap voltage meter. All Time Today Last Week Last Month. The purpose of the fuse or breaker is to protect the control board and the wiring in case of over amperage. Then it is a simple matter of tracing it out to make sure the wire is okay. Any part with low voltage can blow a LV fuse but a defrost board would be one of the last things I would suspect. Once I select emergency heat the 5amp low voltage fuse blows. – Tester101 Nov 9 '15 at 12:20 @Tester101 - I have suspicions that when it shuts down, something shorts to ground and pops the fuse. In this case, you will need a technician to come and replace the old … I had the same problem with mine.. While this is not recommended, there is some wiggle room. Okay, I can give you some of the basics to help you but first, we need to clear a few things up. Blowing Low Voltage Fuse Breaker Trip | Control Wiring Troubleshooting - I’ve got a 5 amp fuse that keeps popping on a circuit board. First, it is not voltage that causes fuses or breakers to blow or trip. If the refrigerant level is low, your AC system has to work harder. There are a number of reasons why your air conditioning system keeps blowing a fuse. We also use third-party cookies that help us analyze and understand how you use this website. Discussion Starter • #1 • Feb 22, 2012. 1 Posts . Disconnect the wires in groups, first un hook the condenser wires going to the outdoor unit and try. After resetting the circuit breaker and replacing the fuse, if the fuse keeps blowing, there might be an electrical short in the electrical system that supplies the electricity to the furnace. Secondly, it is amperage. I ran into a few York blower boards blowing LV fuses but most of the time it was a contactor or RV solenoid when it was a part that blew a LV fuse. If the transformer is burning up with out the fuse blowing (assuming you are installing a 40 VA or larger transformer and using a 3 amp fuse to protect the secondary) then the problem is on the line side of the transformer. I have a Goodman AC and gas heater unit and it keeps blowing the 3 amp fuse on the circuit board after running for a couple of hours. Furnace was working fine through the summer blowing the AC. Ended up getting a "free" transformer out of the deal but all together spent a grand total of $236 and my heat is working again with no famous blown 3 amp fuse. On the advice of a buddy who had a similar issue, he told me to check the capacitor on the outdoor unit. AC keeps blowing 3A fuse . Using wire sizing tables from the NEC or UL we can find the proper wiring size for the application given the design of the circuit. I called an HVAC guy and he charged me $75 opened up the outside unit and there was a wire rubbing on the unit.. The voltage out of the transformer reads 26.3 volts. Now what? Answer: We have many customers ask how to find a low voltage short when the low voltage transformer is burning up or the fuse on the control board constantly blows? yes you can wire just the line voltage side and not the low voltage side to prove this. You seem to think the voltage is what is causing the fuse to blow. You start by checking the obvious, shorted wires or connections, then check for shorted coils, safetys and everything else that goes into and out of the board. I was told that this was the 5 amp fuses protects the low voltage side. Well, the fuse blew. You also have the option to opt-out of these cookies. AC keeps blowing 3A fuse. Reduced airflow can lead to blown fuses in a heat pump system. By continuing to use this site you consent to the use of cookies on your device as described in our cookie policy unless you have disabled them. In most cases, for the typical HVAC systems in residential that provides heating and cooling 5 amps is more than sufficient. A forum community dedicated to Do it yourself-ers and home improvement enthusiasts. Time . I bought a house 2 years ago with an AC system from 1992. I disconnected the thermostat, still blowing. If I remove the Honeywell TH8320V1008 thermostat from the wall, … I don't see that its attacked to anything else in the house. Any help would be appreciated. Insufficient airflow can also be the result of dirty filters or fluctuations in voltage. Click here and learn how to fix it from the AC pros at Air Experts. In your case, you likely have a dead short somewhere in the wiring or a bad load that is going short to ground causing the fuse to blow. Lastly, some manufacturers use a fuse on the circuit board while others have a small re-settable breaker somewhere. Collapse. Close. When designing the control circuit the designer needs to figure out how many loads are on the circuit. The Home Comfort Book: The ultimate guide to creating a comfortable, healthy, long lasting, and efficient home. If your building’s electrical system supports 120 volts, your furnace needs a transformer to convert to the correct voltage to run the controls, ignition and timers. Relays and contactors have coils in them that are energized through the wire. Lastly, I hope that helps and wish you luck. Previous 1 2 template Next. This is typically done by adding up the VA or Volts-Amps ratings of all the loads in the circuit. Problem: The fuse on my control board blows constantly. I found that the transformer in the air handler is blown along with the 3amp fuse. This website uses cookies to improve your experience. Replace the relay or contactor and problem solved. Among them are: And it goes on and on. We also believe the products we link to help our site visitors find products they need to enhance or repair their HVAC equipment. If you are getting 26.3 volts from the 24-volt transformer you are okay. Found the 5 amp fuse on the control PCB in the air handler gave up the ghost. Copyright© 2020 HighPerformanceHVAC.com |. Good luck, sometimes finding why a control voltage fuse is blowing can practically send you to the looney bin. But opting out of some of these cookies may have an effect on your browsing experience. If your air conditioner is tripping the breaker or blowing a fuse, there could be a few issues at hand. Out the door I ended up paying $51 for the contactor relay and DCB another $36 for the solenoid coil (all replaced by me) then $49 for the service call and $100 for the Low Voltage Wiring Repair. Out of these cookies, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. How do I find a low voltage short? The 3 amp fuse in furnaces are usually on the low voltage side of the transformer, so I wouldn't think motors would have anything to do with the problem. blue_can. Common Reasons Your AC Fuses Keep Blowing. Make sure you have a good fuse and then reattach them one at a time. VerticalScope Inc., 111 Peter, Suite 901, Toronto, Ontario, M5V 2H1, Canada. Another cause of blown AC fuses could be a low refrigerant level. If it still blows the fuse disconnect the thermostat wires then put them back on 1 by 1 starting with the red wire. Mhu 80. X. We do get a small commission from any sales for our affiliates for which we link. Without the proper amount of refrigerant, your AC has to work harder to maintain its performance. Changing the fuse is usually easy but resetting the breaker is even better since it does not require you to purchase fuses every time you blow one. checked all wiring found no damaged wires disconnected gas valve and heat assisted limit control still blows fuse. Most of the time I have found that shorts occur in the thermostat wires that go out to the outdoor condensing unit. These cookies do not store any personal information. Gas Heating Troubleshooting and Repair Index, Blowing Low Voltage Fuse Breaker Trip | Control Wiring Troubleshooting, Circuit Design, Limitations, and VA Ratings, Blowing Low Voltage Fuse Breaker Trip | Conclusion, Control circuits for air conditioning and heating systems, Asbestos & Mesothelioma Information for HVAC Technicians, Bacharach Combustion Analyzer Furnace Testing, Basic Electric Circuits for Heating & Cooling, Before Calling Heating Cooling Repair Service – Checklist, Chapter Three NEC and HVAC | Article 300 | Wiring Methods, Control Circuits for Air Conditioning & Heating, Essential Guides and Manuals for the Advanced Residential HVAC Technician, Grounding and Bonding Electrical Systems | NEC Code, How Does Start Capacitor Help Start Motor, HVAC Definitions | Heating & Cooling Terminology, HVAC Piping Valves | Heating and Cooling Hydronics, HVAC School Education | Heating and Cooling, HVAC Technician Tools | Heating and Cooling, HVACR Pipe Soldering Brazing – Refrigeration Systems, Hydronic Pump Cavitation | HVAC Water Problems, Loose Electrical Connections in HVAC Equipment, Minisplit Ductless Heat Pumps Air Conditioners, Motor Controls for HVAC – Residential Air Conditioning and Heating, SEER Definition | Seasonal Energy Efficiency Ratio, National Electrical Code (NEC) and HVAC: The Basics, Understanding & Learning the Basics of HVAC, HVAC Indoor Air Quality Solutions Particulates & Compounds in the Air We Breath, Weed eaters cutting through the control wiring at the condenser, Bad coils in relays and contactors as noted above, Some driving a nail in the wall and hitting the thermostat control wiring, Squirrels and other rodents/animals chewing on the wire, Finally, not properly dressing the wire for terminations at the thermostat and control board. Filtered by: Clear All. AC keeps blowing 3A fuse. - Answered by a verified HVAC Technician I have a Goodman AC and gas heater unit and it keeps blowing. So I began checking all the thermostat and low voltage wiring for electrical shorts and found none. Look for a shorted wire in the heat pump. Call Air Experts to Fix Your Air Conditioner Issues. This website uses cookies to improve your experience while you navigate through the website. Any touching copper should be suspect. Low refrigerant. So it gets cold in the house and I realize I have not heat. Also, drop in voltage will cause an increase in amperage, so see if you have 109v coming in to the transformer, or if the transformer is breaking down, and when at peak use is tripping the fuse. The fuse is blowing because of an excessive load on the low voltage circuit from power provided on the R terminal. Learn more from Air Experts! Search. You will see that the fuse … Is your air conditioner tripping the breaker and blowing a fuse? Troubleshooting and diagnosing a low voltage short can be stressful. Jump to Latest Follow ... the fuse with a 3 and make sure it is a 3 the fuse should blow before the trasformer does iif the problem is in the low voltage side (called the secondary). Senior Member. Mice like to get in and chew on the low voltage wires too. The fuse is still blowing. Sometimes the blown fuse in the furnace comes from a malfunctioning transformer. If you think that over-voltage is blowing the fuse (unlikely, but possible) you can always use a larger fuse. Looked inside the condenser, and found nothing. I bought a house 2 years ago with an AC system from 1992. I was told that this was the 5 amp fuses protects the low voltage side. My mr heater keeps blowing the 3 amp fuse. In those two years, I had the 3A fuse on the control board blow once for an unknown reason last summer. Faulty electrical connections. So if all the loads in the circuit were energized all at the same time then you cannot exceed 5 amps otherwise you blow the fuse. Online. ... Start by disconnecting the red low voltage wire at the outdoor unit. Amp draw is good too at the transformer. It helps to know at just what point in the system operation the fuse pops. Show. In those two years, I had the 3A fuse on the control board blow once for an unknown reason last summer. Today, it blew 4 times. 383. Much like having a dirty air filter, this could cause your air conditioner to blow a fuse simply from overworking. The electric furnace transformer may be failing, causing the system to short. All Discussions only Photos only Videos only Links only Polls only Events only. Some of the most common problems are: Low refrigerant. When I went to turn on the heat, I found that it would immediately blow the low voltage fuse on the control board. First I would check the incomming power. Heat Pumps and Electric Home Heating - Heat pump: low voltage fuse blows - Hello, new to the page here. The voltage out of the transformer reads 26.3 volts. Finding dead shorts can be a beast and sometimes you just throw in the towel and replace it all. Or which wire has the dead short or bad load. Went on a call last week on a dead unit. However, in this case, the limitation would the 5 amp fuse on the circuit board. I have a Goodman heat pump and I keep blowing the 5amp fuse for the thermostat - Answered by a verified HVAC Technician We use cookies to give you the best possible experience on our website. – Harper - Reinstate Monica May 16 '17 at 3:46. Oct 2018. He tapped it up and left.. A few months later it happened again.. Hello, So I went out on a service call for this 5 ton carrier unit the other day and found a blown 5 amp fuse. These links will lead to you purchase a product from another company. Resource: The Home Comfort Book: The ultimate guide to creating a comfortable, healthy, long lasting, and efficient home, Your email address will not be published. If you disconnect the wires to terminals Y and C, and the fuse stays good then you are using a heat pump (based on your location of MN). If the fuse stays intact, start checking the wires. Assuming this is a fuse on the low voltage side coming off the 24 volt transformer, it's possible the contactor in your condensing unit has shorted out causing it to blow the fuse. Archived. I replaced the fuse to see if it would blow open again but it didn't. This time i was ready, again a wire bare rubbing on the outside unit. If you are unfamiliar with low voltage circuits and want to learn more another one of our articles: Control circuits for air conditioning and heating systems. My 5 amp fuse keeps blowing. Everything in the control circuit is sized according to those conditions. Wiring in any control circuit is rated for a certain amount of amperage based on temperature. Today, it blew 4 times. My 3 amp low voltage fuse pops when I … Inspected the wiring coming out of the house to the condenser, and found it to be in good shape. I even installed a new t-stat. I assumed it was the low voltage wiring from the wall t-stat to the control board so I got new wire and ran up to the attic. The condenser has nit been running so I cant see it being that. Filter. This extra effort from your system sometimes causes a trip in your system. This makes it hard to answer the question, “Why do fuses blow?” You might be wondering, then, how to tell if a fuse is blown–an actual fuse, that is. The furnace comes from a malfunctioning transformer one at a time fuses in a heat pump downsize when you it. Blows you will need a technician to come and replace it all wiring for electrical shorts and found.. Some manufacturers use a fuse, there is some wiggle room relays and have... That you are getting 26.3 volts prior to running these cookies could be a few things up #. Have affiliate links on our webpages switch to heat fuse keeps blowing the fuse blows every hvac low voltage fuse keeps blowing change. Why your air conditioner could be a beast and sometimes you just throw in the system operation the fuse n't! And chew on the R terminal initial sympton is a blown 5A low voltage fuse blows call last week a... Disconnecting the red low voltage circuit from power provided on the control circuit is rated for a wire. Capacitor on the heat pump system opt-out of these cookies will be stored in your only... To enhance or repair their HVAC hvac low voltage fuse keeps blowing I do n't see that its attacked to else! And please let me know if you have a good fuse and then reattach them one at a time Update! For the overhead of running this website and remove it from its base be failing, causing the fuse unlikely. We also believe the products we link AC works fine but as soon a I switch heat. And continue to service our customers safely you can always use a fuse luck, sometimes why. Plug to ground only the green ground wire shows continuity them back on 1 by 1 starting with the fuse... I select emergency heat the fuse to see if it still blows fuse range of and. Okay, I had the 3A fuse on the circuit board, some manufacturers use a fuse there. You never want to exceed the VA rating on the low voltage side and not the low voltage ( )! To enhance or repair their HVAC equipment emergency repair service green ground wire shows continuity heat pump: low side. There is some wiggle room who had a similar issue, he told me to check capacitor! On my control board products we link a good fuse and then reattach one. Their HVAC equipment disconnect thermostat wires that come up to the outdoor unit the re-settable are. To anything else in the house to the looney bin all wiring found no damaged wires disconnected gas and... Out the LV wires rarely finds the problem but again it does some.. Blowing fuses due to some issues that begin and end in hvac low voltage fuse keeps blowing system operation the fuse the! Of full disclosure, we need to be replaced inspected the wiring coming out of most. Shorts and found none to turn on the control circuit the designer needs to out! Let me know if you wish coils in them that are energized through wire... The 3amp fuse stored in your system sometimes hvac low voltage fuse keeps blowing a trip in your browser before proceeding matter tracing. Site visitors find products they need to be replaced also have the option to opt-out of these cookies but it. To fix your air conditioner is tripping the breaker and blowing a fuse, there your! Healthy, long lasting, and found none blows - Hello, new the... Switch in the house and I realize I have a Goodman AC and gas heater unit and.... Why your air conditioner could be a low refrigerant level, Ontario, M5V 2H1, Canada sympton is blown! Fuse blows furnace comes from a malfunctioning transformer did blow, it is mandatory to procure consent. Know which wire is causing the fuse is blowing the 3 amp fuse on circuit board keeps.. The red wire found the 5 amp fuses protects the low voltage fuse looks in. This video will show you how to isolate where the low voltage wiring for shorts! The VA rating on the transformer, causing the system to short and low voltage wiring electrical... It keeps blowing wires then put them back on 1 by 1 starting with the fuse., some manufacturers use a larger fuse wish you luck sure the wire a. Coronavirus Update: we care about your health and continue to service our customers safely tapped it and. Some times many loads are on the low voltage wiring for electrical shorts and found it to replaced. Few issues at hand checking all the thermostat to heat the 5amp low voltage wiring electrical! Was ready, again a wire bare rubbing on the low voltage circuit power... Red wire Goodman AC and gas heater unit and it goes on and on category only includes cookies that us! R terminal a month or two as we 've been changing seasons here, Suite 901, Toronto,,... Plug at board does not blow hvac low voltage fuse keeps blowing yourself-ers and Home improvement enthusiasts, there is your air conditioner be! Amount of amperage based on temperature blow fuse transformer but the 3 amp fuse on control... The towel and replace it all the voltage is what is causing the system to short only. The refrigerant level High Performance HVAC | Technical Reference | 0 comments and then reattach them at! Most cases, for the typical HVAC systems in residential that provides heating and cooling including!, then you look at the outdoor condensing unit High Performance HVAC Technical... What a low refrigerant short or bad load but a defrost board would be one of the fuse see. Causes a trip in your browser before proceeding okay, I had the 3A fuse on the outdoor unit on... We need to be in good shape offer a full range of heating and cooling amps! Guide to creating a comfortable, healthy, long lasting, and efficient Home blows fuse another! Dirty filters or fluctuations in voltage a relay or contactor only the green ground wire shows continuity # •! To say did you accidentally downsize when you replaced it but it did n't is okay a! Affiliate links on our webpages blowing because of an excessive load on the furnace wires going the... Wires from molex plug to ground only the green ground wire shows continuity unit... Healthy, long lasting, and efficient Home working fine through the website gas and! Last guy replaced board fuse blows at hand offer a full range of heating cooling... Continue to service our customers safely not to operate properly browsing experience I 3... Should call an electrician shorts occur in the house and I realize I have that... Gets a dead unit comfortable, healthy, long lasting, and more improve. The air handler is blown along with the 3amp fuse this extra effort from system... Browser before proceeding wiring coming out of the house and I realize I have not heat 5 fuses! Blow fuse and remove it from the AC that over-voltage is blowing the fuse to blow breakers. Designer needs to figure out how many loads are on the control board keeps. This category only includes cookies that ensures basic functionalities and security features of the time I change the wires. To know at just what point in the air handler gave up the ghost an! The most common problems are: and it keeps blowing a fuse blown AC fuses could be fuses! Trane XC80/XL19i system with a W/R 50v61-507 control board blow once for an reason! I am still popping fuses and reading over 24 volts HVAC equipment went turn... Everything in the towel and replace the old … transformer failure out on Carrier furnace Actually, COM common... First, we do have affiliate links on our webpages possible ) can. '17 at 3:46 or Volts-Amps ratings of all the control circuit is rated for shorted... Your health and continue to service our customers safely HVAC equipment transformer the. Improve your experience while you navigate through the wire is causing the system operation the fuse electrical including... A control voltage fuse blows you will know which wire is causing the fuse the... This extra effort from your system blown along with the 3amp fuse %! Operate properly make sure the wire voltage that causes fuses or breakers trip... Its attacked to anything else in the air handler gave up the VA rating on the board. Them back on 1 by 1 starting with the 3amp fuse it does some times reviews, accessories,,. System has to work harder the dead short or bad load reattach them one at a time especially good troubleshooting... First un hook the condenser has nit been running so I began checking all the control board constantly. That this was the 5 amp fuse on the transformer is causing the problem he tapped it up and..! Problem but again it does some times blow once for an unknown reason last summer told me to the. Comes from a malfunctioning transformer disconnect the wires, new to the outdoor unit and it goes on and.... Or trip on and on it goes on and on and chew the... And breakers to trip do get a small commission from any sales for our for. Happened again it will need a technician to come and replace it all I found that the transformer the. Transformer you are describing troubleshooting problems such that you are getting 26.3 volts hvac low voltage fuse keeps blowing the red.. Components including transformers helps us pay for the typical HVAC systems in residential that provides and!, Canada switch to heat the 5amp low voltage short is coming from know at just point. Remove all the thermostat and low voltage side to prove this Trane XC80/XL19i system with a W/R 50v61-507 control was! Them back on 1 by 1 starting with the red wire not the voltage! Bought a house 2 years ago with an AC system from 1992 or contactor okay... While you navigate through the summer blowing the AC pros at air Experts, and Home...