Pacbrake 30 amp fuse

[B.G. Smith]

Brake is five years old, worked perfect until now. In last month the 30 amp fuse has blown two times. Any suggestions as to where I should start to determine the cause? bg

 

[petersonj]

Brake is five years old, worked perfect until now. In last month the 30 amp fuse has blown two times. Any suggestions as to where I should start to determine the cause? bg

I would treat as any other electrical circuit. First, verify that the fuse feeds only the compressor. If this is so, then inspect the wiring from the fuse to the compressor for any possible short to ground condition. If the wiring checks out okay, then make sure the compressor is not cycling excessively and is cycling within its designed cut-in and cut-out pressures.

If everything checks out okay, it is likely the compressor is failing caused either by excessive load or internally shorting to ground.

- John

 

[p-Bar]

Check to make sure the compressor isn't running fulltime (leak in the system). Do this by turning the ignition key on only then turn the brake on it should run for 5 seconds. The compressor could be on it's way out you can put an amp meter inline and see what it's drawing. Ditto the above comment

 

[B.G. Smith]

Update: Cleaned and tightened batt. terminals. Weren't dirty but drivers side were not real tight. Ran a few days, thought it was fixed. Blew again and I pulled the connections to compressor (yes the 30 amp fuse only runs compressor) hooked up amp meter and ran compressor start and stop several times, never showed over 15 amp draw?????. Last evening I removed all the protective tubing from the wires, no bad places in wire. Ran the compressor some more, no overload? The way it is wired now the compressor runs even if you don't use the exhaust brake, I am going to put a switch in the line (as suggested by the manufacturer) so I can cut it off if I wish. Yeah I know, why would I. I am also going to replace the fuse holder is case it has some current loss problems. So that's where I am right now. Thanks for the replies. bg

 

[p-Bar]

Did you have a load on it? Maybe struggling to make higher pressure?

 

[KATOOM]

I would hope that you contacted Pacbrake since its their product so they could have the best knowledge, and/or have a diagnostic procedure to help.

 

[B.G. Smith]

p-Bar, I let it run till the pressure switch cut it off a couple of times with the meter on it. KATOOM, haven't contacted Pacbrake. bg

 

[Ozymandias]

Does this compressor have a check-valve like the ViAirs have that bleeds the pressure line after the motor stops?
With a faulty check-valve the motor have to start against the tank pressure and that can lead to very high amps and even a burnt up compressor - acording to the ViAir manual.

 

[p-Bar]

I think Ozy hit the head on the nail.

 

[B.G. Smith]

There is an inline check valve right at the exhaust of the compressor, 1/8" pipe threads. If the valve is not holding wouldn't that indicate that the compressor exhaust side valve is also not holding?

 

[B.G. Smith]

Update: Pumped up the air tank today and checked for leaks in system, Gage went from 125# to 120# in about 20 seconds. Checked for air coming back through compressor. None to be detected. Removed the check valve and put air pressure back on, blowing through like wide open. Replaced the check valve and now holds pressure. Looks like Ozymandias nailed the problem. Thanks to all. bg