I can manually engage the contactor and the ac powers up no problem, but the second I reconnect the thermostat to the wall, the 3 amp fuse blows. 99 ($1.60/Item) FREE Shipping. In previous blog posts, we talked about the differences between IEC vs. NEMA and discussed the basics of a motor starter. mask,front desk still blows. Blowing Low Voltage Fuse Breaker Trip | Control Wiring Troubleshooting - I’ve got a 5 amp fuse that keeps popping on a circuit board. So, I went to start it yesterday, and nothing. Calculate Size of Contactor, Fuse, C.B, O/L of DOL Starter Calculate Size of each Part of DOL starter for The System Voltage 415V ,5HP Three Phase House hold Application Induction Motor ,Code A, Motor efficiency 80%,Motor RPM 750 ,Power Factor 0.8 , Overload Relay of Starter is Put before Motor. Send help. 3 amp boiler fuse. Discussion in 'Plumbers' Talk' started by Matt Vernon, Nov 12, 2016. Hey, I have exhausted my troublshooting ability...I need some direction. How long have you been dealing with this? The unit runs ok for a few days and presto the fuse popped again. What is my next step? - the F3 4 amp fuse keeps blowing - the T3 Resistor looks bad (see pic) So could the T3 Resistor (if bad) cause the F3 to blow? TRANE Replacement Time Delay Fuse, Single Element, 300 VAC, 3.2 AMP, 24V Control - Box of (5) $21.95. FREE Shipping. $7.99 $ … 1. I replaced it and everything worked fine. I also found several pinched wires as well. the amp draw on the comp … read more. Compstudio 10Pcs F12AL250V 6X30MM 12A Fast Blow Fuse 12 Amp 250V F12AL Glass Fuse Fast-Acting Fuse (1/4" x 1-1/4") 3.5 out of 5 stars 2. M. mickshields. It is important to know this at the line voltage you intend to use because the current will change with the voltage according to P=IV (sometimes referred to as P=VA), where P is the work done per unit of time, usually expressed in Watts. Vocational, Technical or Trade School. Cylindrical fuses consist … YOLISTIC (Pack of 10) 12 Amp Slow-Blow Time Delay Fuse Ceramic 6x30mm . (If NO, and the fuse has blown again. Contractor's Assistant: I'll do all I can to help. Steps. I have a Goodmand Heat Pump Package Unit M#GPH1342M41AC unit is about 7 months old. M2, M3 and M4 were running ok. With blown fuse still installed checking from line side of fuse L1 and load side of fuse L1 for M1, I get 480 volts? The unit fired RIGHT up and ran solid for about 5 minutes .... then blew the fuse again. 3 amp fuse blowing on air handler board....narrowed it down to red wire out to heat pump.... red wire traces directly over to defrost board...I see a little discoloration on two resistors on the board … read more. HVAC Technician: BillyHvac, Journeyman HVAC Tech replied 10 years ago. This load amperage is the amount of current required to power your device at the line voltage. I have a carrier cental air unit that keeps blowing 5 amp fuses. I replaced it and it blew again immediately. 1,793 satisfied customers. A valve amp blowing fuses can be a number of things, but in this case I suspected that the amp probably had a faulty power valve. What is causing the fuse to blow? Hey, I have exhausted my troublshooting ability...I need some direction. (See manufacturing data) Stock 70 amp contactor Performance 200Amp Contactor Stock 70 amp contactor Performance 200Amp Contactor Stock OEM 100 amp contactor I'm far from an electrical expert so I have replaced the fuse and after the heat is on for awhile the fuse will blow and then I have cool air blowing. The fuse would blow when the unit shut down after a cycle or two, that suspect me to check anything that’s working at the end of the heating cycle. Motors are what we call “inductive” loads, meaning there is an induced voltage due to the rotational effects of the motor. The issue, I assume line one (farthest left bank in the breaker) is consistently blowing the fuse … This turned out to be true. That means that your 3 amp fuse could be anywhere between 2.4 and 3.6 amp. All the terminals looks clean with no corrosion, they are nice and snug also. For example, if you have two applications, both using the exact same motor, but in one case the motor will simply be turned on for long periods of time, while the other will be turned on/off constantly, you will likely use two different IEC contactors for each application. My 3 amp fuse is blowing on the circuit board. BillyHvac, Journeyman HVAC Tech. Replaced contactor and 3 amp fuse and still blowing fuse. Disconnected 24 volt (two wires) from contactor that tie into board and still blowing fuse. Please advise on how to troubleshoot problem.Thanks This page is a catch-all for folks that want to ask a question when their air compressor is blowing fuses-breakers and their particular issue is not covered on the other pages. An incorrectly specified IEC contactor may work for a period of time, but the lifespan will be severely reduced. Hello everyone, I've used some advice from previous threads to get me as far as I am with this issue, but I'm stuck again. … After a while the A/C turned off. If the wiring is shorted, the contactor is stuck or the contactor coil is bad, this could cause the fuse to blow. I went a head and replaced it. If you went through this test and it suggests a bad tube, continue on to locate the bad one: Testing Rectifier Tubes (5U4, 5AR4, 5Y3): Gaztech. So I replaced the fuse, put the panel back on, and it didn't turn on. Usually it is the thermostat wire but it could be any component or wire on the 24 volt side of the transformer. The voltage out of the transformer reads 26.3 volts. With a good fuse in the AC work fine and you can switch the fan from Auto to Fan on with no problem. Also Calculate Size of Overload Relay if O/L Relay Put in the wingdings (overload is placed after the Winding Split into main and delta… If you were to put a 4 amp 50 volt time-delay fuse in it's place, you would still provide short-circuit protection while bypassing this slight(ish) problem. This is important because these will in part, determine which contactor you use. #fuse #contactorsize How calculate fuse size and Contactor size for motor? Blown 3 Amp Fuse in AC quick fix - Save $300-$500 - YouTube Proceed with caution, as some fuses can explode when they are blown. It’s not just a question of what type of device you are powering, but also how it may be used. I know the T-stat wire was good, replaced all new. Checking line side L1 to load side L2 I get 480 volts. I have Lennox ac system and the fuse #3 amp in blue wire keeps blowing. Well tonight, randomly, the ac shut off. The 5 amp fuse on my control board blows as soon as you ask for heat. I have a furnace/coil that for the past 3 years has been blowing the 3 amp fuse on the board 2-3 times an entire heating season. Matt Vernon New Member. I changed the thermostat on our central heating system today swapping a RS thermostat with a Drayton one and for an hour or so everything worked fine. I did and found out it was burned. As soon as you request heat the fuse blows and when I try to run the fan to on nothing happens. 3 amp fuse blowing on air handler board....narrowed it down. current rating (i.e. IEC uses utilization categories, or “codes”, to describe specifically the type of electrical load and duty cycle of the load(s). They make resettable fuses in 3 and 5 amps called poppers. Motor Full Load Amps Calculator. $19.25. Fans, central vacuum, Hermetic refirgerant compressor motor control with manual resetting overloads, Hermetic refirgerant compressor motor control with automatic resetting overloads, Control of resistive loads and solid state loads with opto-coupler isolation, Control of solid state loads with transformer isolation, Connecting and disconnecting under no-load conditions, Switching of resistive loads; including moderate overloads, Switching of mixed resistive & inductive loads, including moderate overloads, Switching of motor loads or other highly inductive loads, Protection of circuits, with no rated short-time withstand current, Protection of circuits, with a rated short-time withstand current, Non Inductive or slightly inductive loads, resistance furnaces, heaters, Shunt-motors, starting, plugging(1), inching(2), dynamic braking of motors, Series-motors, starting, plugging(1), inching(2), dynamic braking of motors, Control of D.C. electromagnetic loads having economy resistors in the circuit, Switching of resistive loads, including moderate overloads, Switching of mixed resistive and inductive loads, including moderate overloads (i.e. A clear plastic cap that just pops off but the lifespan will be jogged or frequent... 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