What is a 10-ton air conditioning unit? A 10-ton air conditioning unit is a cooling system capable of removing 120,000 British thermal units of heat per hour from the air in the building to which it is attached. In this system of measurement, 1 ton is equal to 12,000 BTUs of heat extraction per hour. How many BTUs do you need in an air conditioning unit to cool a 12 foot by 12 foot room? What is a 4-ton Carrier air conditioning unit? What is involved in installing a heat pump for residential heating? Prior to the invention of modern air conditioning, total cooling capacity was measured in tonnage, referring to the amount of ice that was used. The amount of heat that is necessary to melt 1 ton of ice in 24 hours is 286,000 BTUs, or about 12,000 BTUs per hour. This is the basis for the measurement of modern cooling capacity. Learn more about Heating & Cooling How do you size room air conditioners? Use the area of a room to determine the proper air conditioner size estimate, which is measured in British thermal units per hour.

A 100- to 150-square-foo... How do you compare the costs of a replacement HVAC unit? To compare the cost of a replacement heating, ventilation and air conditioning unit, it is important to consider factors, such as price ranges for differen... What is an air conditioner drain alert? The drain alert on an air conditioning unit indicates that water, formed as condensate on the units' evaporator coil and collected in a pan, isn't leaving ... How does a gas furnace work? A gas furnace consists of two parts, an outdoor air conditioning unit and indoor furnace that work together to draw in, heat and circulate winter air and c... What is the unit for frequency? What size room will a space heater heat? Where can you buy a Deco breeze fan? Where can you find a user's manual for Dunkirk boilers? How do you find a local Superior Fireplace dealer? Where can a Honeywell th8000 thermostat be purchased? AC Unit Maximum Breaker Re: AC Unit Maximum Breaker

Is this new construction? Because it is only 5 amps I would look closely at the wire and insure that it is rated for the higher amperage under an inductive load. It may be wrong IAW the Mfg. but an over current device is there to protect the wire on the branch not the appliance. If the wire to the unit is rated for the breaker size at least you won't have a fire hazzard to the unit. Also a concern is if the breaker is rated for HVAC use. Also consider that the condenser may have internal wiring matched to the Max Fuse/Breaker Rating indicated on the label, and an older oversized breaker may not trip if the compressor motor locks up ... which could complete fry the equipment ... IMO report it as a defect needing evaluation/repair and call it a day ... Consulting Engineer & Inspector LIU CW Post Adjunct Professor I am absolutely amazed sometimes by how much thought goes into doing things wrong ... every HVAC guy and electrician I speak to say it is alright to go to the next 5 amp size.

They want to see that the wire size is consistent with the higher size. None of them will change the breaker when called out to confirm this. At ITA I remember them saying that the wire size can be smaller if matched to the minimum ampacity rating on the dataplate.Cheap Washer Dryer Combo For Sale Being an HVAC tech for a long time that is what would happen. Digital Camera Taken ApartThe tech will say no problem. Discount Curtains NjAs long as the breaker is correct for the wire size 5 amps isn't a big deal. Start up amps can be in the 60-amp range. I've seen units under this same scenario (25 amp nameplate) that would cause nuisance trips when a 25-amp breaker was installed and when the 30-amp breaker was put in the trips stopped and there were never any problems.

It is over fused if a breaker larger than the manufacturer's label calls for is installed. Here is a good explanation I picked up somewhere: A/C condensers contain a hermetically sealed compressor motor as well as a fan to circulate air across the coils. The rules for protection to motor circuits are different than for circuits with simple resistive loads. When a motor first starts , it draws a much higher amount of current than it does after it is running. The high "inrush" current can exceed the rating of a breaker or fuse sized to protect the wire. The inrush current lasts typically only about 6 electrical cycles, or 1/10th of a second - less time than it would take to damage the wire or its insulation. However, if the overcurrent device is sized to protect the wire against overloads, the device might trip, and the machine would not be able to start. Motor circuits get around this problem by dividing the two separate functions of an overcurrent protection device. "Overloads" are currents that can damage a circuit if allowed to continue for a sufficient time, whereas "short circuits" and "ground faults" are high currents that can cause immediate damage.

Large motors and air conditioners separate these overcurrent functions. The breaker or fuse ahead of the air conditioner only protects against short circuits and ground faults. Overload protection is built into the compressor itself. The wire to a condensing unit must be large enough to allow the equipment to start. The device is therefore NOT sized to protect the wire against overloads. It is not uncommon to see a 50 Amp breaker on a #10 wire. The wire is protected against overloading by a separate thermal protection inside the compressor. How do we know what the motor requires for wire size and proper fuse/breaker protection? It's all on the mfg. label attached to the appliance. If the label calls for fuses, there MUST be a fuse in the disconnecting means, not a circuit breaker. If the label calls for a "HACR" type breaker (Heating, Air Conditioning and Refrigeration), then that is the type of breaker that must be used. If the label simply states "maximum sized over current protection" then any form of overcurrent protection may be used.

The HACR designation is not always visible on a circuit breaker once it is installed inside a panel or disconnect. Note on the label taken from a Lennox A/C data plate:FUSE - 25 UL (CSA is a Canadian standard. We use UL in the U. S.)UL - Not allowed in U. S. All this means is the MINIMUM wire size required is #12 (solid copper); the MAXIMUM rating of a fuse (if a fuse is used) must be 25 amps and the MAXIMUM rating of a circuit breaker (if used) must be 25 amps AND the breaker must be a HACR type.However, if the over current device is sized to protect the wire against overloads, the device might trip, and the machine would not be able to start. "it draws a much higher amount of current than it does after it is running." This is called an inductive load. "The high "inrush" current can exceed the rating of a breaker or fuse sized to protect the wire. " This is why HVAC breakers must be rated for HVAC use. The wire, breaker (to protect the wire), and type of breaker must be correct and is reflected in the "minimum circuit data".

Michael MerinoMerino's Home Inspection & Education Inc." IF YOUR INSPECTOR IS NOT USING THERMAL IMAGING, YOU'RE NOT GETTING THE WHOLE PICTURE �Jeff Pope JPI Home Inspection Service Santa Clarita Home Inspection Originally Posted by jpope I understand that the circuit is over-fused, but the appliance is connected to that circuit. If for some reason it were to draw more than 30 amps (outside of the inductive load) the breaker will not trip. I am confused by the differing opinions. I have been told by inspectors it is OK, and some say it is not. Some say that you can over-fuse the AC up to 40%. I do not seem to be able to find a definitive answer. I am thinking that if the max breaker is supposed to be 30 amp, then the breaker should be 30 amp not 50 amp, even if the conductor is the proper size. Professional Certified Master Inspector In Edwardsville, Glen Carbon, Godfrey, Maryville, Fairview Heights, O'Fallon and surrounding areas of Illinois Metro-East