Replyyou need a service tech!
Regular Guest
I have a rooftop HP aprox 10 yrs. It keeps blowing fuses. I've cleaned the condenser & evap coils, changed the contacter, changed the cap & added a hard start. all pressures are good. Sometimes it will run for 2 months and sometimes for 2 hrs. depending on the weather. Should I replace the compressor or the whole unit?
Regular Guest
you need a service tech!
Regular Guest
Loose fuses, poor connections @ disconnect?
Are they just blowing on hot days?
____________________________________________
We're not satisfied, until you're not satisfied
Regular Member - Bad email
Check supply wiring size, length of run and breaker type / size.
Regular Guest
Most likely loose fuses in the disconnect. Replace disconnect to be safe and double check amps, wiring, make sure it is not short cycling. OR just cut a piece of copper the same size as the fuse and ....
Professional Member
........you'll find what is blowing them guaranteed!Originally Posted by njcontractor
I have heard that described as an extreem slow blow fuse!!
Quote
Engineers like to solve problems. If there are no problems handily available, they will create their own." Scott Adams
"We can't solve problems by using the same kind of thinking we used when we created them."
Albert Einstein
Professional Member*
Besides checking the amps check your voltage at the contactor and on the electrical panel. You could have low voltage.
"I could have ended the war in a month. I could have made North Vietnam look like a mud puddle."
"I have little interest in streamlining government or in making it more efficient, for I mean to reduce its size. I do not undertake to promote welfare, for I propose to extend freedom. My aim is not to pass laws, but to repeal them. It is not to inaugurate new programs, but to cancel old ones that do violence to the Constitution."
Sen. Barry Goldwater
Professional Member
You mentioned, depending on the type of weather !! What type of weather ??
I'll assume, hot humid, maybe raining !! (maybe not) For the sake of arguement - I'll continue !! In my opinion, secure the power off, remove all access doors, very carefully inspect all wiring, devices. Check any place the wires come in contact with the cabinet surfaces, look for rub throughs, any type of black carbon tracking, is sure sign of a fault. Use a quality Ohmeter to test all wiring, devices. If a Meg-ohmeter is available, test all high voltage conductors. You memtioned a hard start kit, so it is single phase, don't meg- ohm the start components, only the motor windings and conductors. Also test the evap and condenser motors, same rule applys. With the disconnect open, test the power wiring from the disconnect to the unit, again do not meg ohm small components, only the power wiring. Be sure you have the correct type of fuses. Dual element, time delay type, that are new, always change them out in pairs, even if one tests O.K. Is there a time delay in the circuit to keep the compressor from short cycling, not on the T'stat side, but last in line to the compressor, if not add one. Measure the voltage and amperage of all motors - compare to nameplate. With a hard start kit, the compressor should start right up quick. Measure the inrush current if your meter has that option. Be sure the fuses are of sufficient size, be sure all electrical connections are tight. Inspect the compressor motor terminals, and other motors if applicable. The refrigeration system needs to operate properly as well. Correct system pressure are required, and can cause high current if all is not well. Be sure to Lock Out the Disconnect when performing all of the work. Saftey first. These are the first areas to check when attempting to locate such a problem, just my opinion !!
Regular Guest
that's funny and scary. would you recommend ACR or Type M.
Professional Member
those copper pipes are called "no blow" fuse and I have removed many
matt
Professional Member*
make sure all your covers are on the contactors...an ark on closing could blow the fuses.is it just one at a time or are you coming up on 2 blown fuses each time.if your 460V 3 phase moisture around the blocks will cause a jump across phases and blow a fuse.could be just as said here a different style fuse to take that locked rotor draw on start...it is 3 phase your working with there?
"when in doubt...jump it out" http://www.youtube.com/watch?v=U1qEZHhJubY
Professional Member
I've had issues here and there with power strikes (not lighting hits) into the main feed to my building which has caused units to go down pretty quick due to fuses in the disconnect blowing out. Not every phase though, sometimes just one of the phases from ComEd.
Banned
clgman you need to watch what you post in a non pro forum!
you might get someone seriously injured if they do what you explain!
.
Last edited by Airmechanical; 07-12-2007 at 02:51 PM.
Professional Member
Yes, your right !! This can be a potentially dangerous business. Not for the untrained novice. What does any piece of HVAC service literature state, or IOM, work to be performed by an experienced(or qualified HVAC)technician or some facsimile of that description. So, with that in mind, let the clueless be put on notice - don't touch it , if you don't realize all the potential hazards a piece of equipment may represent. BE CAREFUL, IT MIGHT JUST SAVE YOUR LIFE !!!!
Regular Guest
first if your not qualifed call some on who is second check all electrical conections third meger out the compressor ,and fan motors
Regular Guest
So when it catches fire - burns the building down - kills several people - You are going to take the rap ????
DO NOT follow this suggestion - Fuses are there for two main reasons to protect the equipment and to protect you.
Fuses do NOT blow for no reason - find the cause and fit the correct fuse for the equipment.
Paula
Regular Guest
Paula is right fuses and circuit braekers are made to protect the equipment and especially the owner (tenants).So when it catches fire - burns the building down - kills several people - You are going to take the rap ????
DO NOT follow this suggestion - Fuses are there for two main reasons to protect the equipment and to protect you.
Fuses do NOT blow for no reason - find the cause and fit the correct fuse for the equipment.
Paula
Seek help from qualified AC technicians around your vicinity, Ask for a NATE
Certified. They can help you with your problem. Don't try to do it if you are
not capable of doing it.
I observe the problem is repetitive as per your info.
Don't waste time, find a NATE certified Technician to resolve the problem
before you set the building on fire, if so.. get ready to call 911 rather than a NATE technician.
hahaha...
peace,
yp5
Professional Member*
id shoot the inf at the disconnects connection points n the fuse .. i use my black sharpie on the fuse if its a shiny new one to get good reading .. this is one way i use to check the connections & contact points on a disconnect .. but this may not be the only issue with your unit .. just a thought for ya ... & yea definetely dont use copper pipe instead of fuses
Professional Member
Your obviously impressed by, or endorsing Nate personnel, thats fine. However, please review proper sections of the NEC, or whatever electrical code has jurisdiction in your area pertaining to Circuit Overcurrent Protection and what fuses actually protect.
Professional Member
fuses.......and circuit breakers......protect the wire.....the equipment...motors...compressor motors have their own methods of protection.
Posting Permissions