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Unit keeps blowing low voltage fuses intermittently

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I f this is central unit you have a low voltage short. If it does not happen all the time it could be a contactor or a control. On several occasions I have found a wire rubbing outside on the condensor and blows the fuse when the wind blows chech these items. Rus

Posted on Jul 14, 2009


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I have an ir ssr-up6-30-125 that keeps blowing control fuse on transformer

is this a a/c? blowing fuse is usually related to a low voltage problem. check low voltage wires ( SMALL WIRES THAT ALSO RUN THERMASTATE) CHECK FOR BARE WIRES, broked ,cracked ect..if this is a split a/c ..... has inside and outside units. disconnect wires going to outside and see if it still blows. if not repair or replace wires. wires going outside are usually the problem

Jan 30, 2014 | Heating & Cooling

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Error 54 please

Precor Error 54, Target Pulses Lost During Operation Probable Cause 1. Blown F2 fuse.
2. Gear motor wiring is damaged or has intermittent connection.
3. Gear motor is bad.
4. Gear motor target is damaged.
5. Lower PCA is bad.
Corrective Action
  1. Disconnect power from the unit. Remove the F2 fuse from the lower PCA. Using an ohm meter, measure the fuse for 1 ohm or less. If the reading is considerably high, replace the fuse. If the fuse is blown, inspect further for the cause to avoid the fuse blowing again. Inspect for damaged gear motor wiring or a bad gear motor. Replace if necessary.
  2. Thoroughly inspect the gear motor wiring for damage or intermittent connections. Repair or replace damaged wiring or poor connections as necessary.
  3. With unit disconnected from power, disconnect both wires from the gear motor. Using an ohm meter, check for approximately 9 ohms through the gear motor wiring. If the reading is considerably high or low, replace the gear motor.
  4. Inspect the gear motor target for rips, tears, or bad scratches. If any of these are found, replace the target.
  5. During the start up sequence, check the voltage at the gear motor. Voltage should be approximately 12VDC. The voltage should only be present between the time the sequence was started and the error 53 occurred. If the voltage is considerably low or absent and the F2 fuse proved good, replace the lower PCA.
Precor Error Code 54

Nov 02, 2013 | Precor Efx 5.17

1 Answer

American Standard AC has started blowing fuses about 1x/2days - any ideas why & is it safe to just keep replacing the fuse?

Hello, the low voltage fuse will blow if the thermostat wires are shorting togethur or ground, or if the contactor coil on the outside unit is shorting to ground.

Jul 11, 2012 | American Standard Heating & Cooling

1 Answer

Bryant 650a furnace keeps blowing 3 amp fuse

If you keep blowing the 3 amp fuse it usually means you have a short somewhere in your low voltage control wiring or maybe within the wiring of your control box. I would ecommend using your ohm meter or continuity tester and start tracing each circuit unit you find where it is grounded at. It usually is in the thermostat wire where a rat or just an exposed piece of wire is touching metal somewhere. Just keep in mind that it could be a very small part of a wire touching the metal. Also check your low voltage wiring and make sure you have everything wired correctly if any of that has changed. At least you have a 3 amp fuse to blow instead of something else more costly to repair! Hope this helps.

Feb 28, 2012 | Heating & Cooling

1 Answer

My nordyne e2eb elec furnace keeps blowing the #3 atc fuse

Hi, if it keeps blowing this control fuse, you have a dead short on your secondary side, low voltage, 24 volt side of this unit.Look at the thermostat wire at the unit where you are to see if any thing is scored and touching metal. Every part that operates on 24 volts such as a pressure switch, thermostat, flame roll out switch, and even the coil on the contactor that starts the compressor could be shorted. This is a package unit, 3 and a 1/2 tons.Take the low voltage wires loose from the unit and see if the fuse holds. If it does, you have a short in the stat wire any where from there to the stat. If not, most likely the control board is bad. Take out the screws after killing power and work the board out slowly to see the back of it. If its shorted you will see hot or burned spots on it. Its a process of elimination on the low voltage componants. Please let me know how its going, I will be here to help.

Nov 26, 2011 | Intertherm P3RA-042K Air Conditioner

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I have a duo therm model 57915531. i have checked the breakers all the fuses and the thermostat. i have found a 3 amp fuse in the control panel of the roof unit. this fuse was blown. i replaced it and it...

That unit has a thermostat I believe and 12 or 24 volts to power it. The 3 amps tells me it may be either line or low voltage, see manual. the fuse blows due to a short in the control circuit, a transformer if low voltage.

Sep 10, 2011 | Dometic Rooftop RV Air Conditioner

1 Answer

Soundcraft GIGRAC 600 pre-amp power supply keep blowing the low valve resistor 1ohm. they are the resistor just before the bridge rectifier, for the low voltage feed. Once resistors replaced the unit...

The resistor is acting as a fuse and will continue to blow until you fix the REAL problem. LIKELY the filter capacitor(s) beyond the bridge rectifier are failing. One needs to use test equipment to measure the current through the resistor and see if it is reasonable. The capacitors can heal briefly and then start to short. One should also check the rectifier in operation with an oscilloscope as one diode could intermittently short.

May 04, 2011 | Soundcraft Gigrac 600 Powered Mixer

1 Answer

Thermostat keeps blowing fuses

There is a short in one of the thermostat wires. The fuse is triggered on the low voltage side of the unit. Replace the wires.

Feb 08, 2010 | Coleman Heating & Cooling

1 Answer

Kenmore Micro/Oven fuse keeps blowing

Disconnect the connector to the primary winding of the high voltage transformer. Put a new fuse . If the fuse is not blowing the problem may be in the secondary side of the high voltage transformer. Chek the highvoltage diode, capacitor, magnetron respectively. you can also check the primary winding of the low voltage transformer.

May 23, 2009 | Microwave Ovens

2 Answers

Blowing 3amp fuses

You have a low voltage short. A lot of low voltage shorts come from the wires that go out to the outdoor unit. Go outside and inspect those wires and that they are in good condition. Also check for any splices in those wires that they haven't degraded in any way. This is the only thing that will blow the fuse. That's why it's only 3 amps and based on the size of your fuse, it's a gas fired unit right? Have a great day!

Apr 10, 2009 | Ruud UBHC Air Conditioner

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