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Fridge compressor problems!

Posted: Thu May 26, 2011 9:38 am
by pipeboyswe
Hi i just got my hands on a fridge compressor and i cant get to run.
I have connected:
blue to the upper N
brown to L
and yellow/green to ground
What is the problem? Is the wires connected wrong or is the compressor broken?

It is a Danfoss Tl2.5A

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Posted: Thu May 26, 2011 9:52 am
by Technician1002
You may need to borrow a multimeter at this point to troubleshoot that compressor. Sometimes the start relay goes bad. When you apply power does the relay click at all? Does it draw any power?

The relay contains an overload (self resetting thermal circuit breaker). If the compressor is stuck, when power is applied, it will click for start and after a second or two click again as the breaker pops. After about a minute this will repeat.

If the run winding is burned out in the compressor, the relay won't click at all when the power is applied as current in the start winding operates the start relay. A bad start relay will do the same thing.

An ohm meter will be required to measure the winding resistance between the run and common and start and common on the compressor itself. To reach those terminals, the start relay needs to be unplugged from the compressor. It pulls straight off to expose the 3 pins underneath.

The power cord colors are correct. Brown is hot, Blue is neutral and yellow/green is ground.

Be sure the compressor is right side up when testing an not on it's side. Some relays are operated by gravity and won't work on the side.

Posted: Thu May 26, 2011 10:14 am
by pipeboyswe
Iv got two compressors hooked up the same way but i cant hear a klick or anything none of them will run :(

Posted: Thu May 26, 2011 10:23 am
by Technician1002
It is time for troubleshooting. Do you have a multimeter? If you work with electricity, one is essential. They are not expensive except for pro models.

I've been able to find them for less than $30. Commercial models the pro's use cost more such as the Fluke line. Hobby models less likely to survive a direct lightning strike and without calibration certification are much less expensive. You don't need laboratory grade certification to test a compressor so don't waste the money for it.

Do get one that is protected on the ohms scale against accidental connection to line voltage. Forgetting to switch from ohms and testing for power someplace will instantly fry a too cheap of a meter. One protected against that mistake is cheap insurance and well worth the expense.

Posted: Thu May 26, 2011 10:33 am
by dewey-1
You need a wire from the C terminal to L terminal.
This will simulate the thermostat switch.

This link will show a wiring diagram.

http://www.ra.danfoss.com/TechnicalInfo ... 42s402.pdf

Posted: Thu May 26, 2011 10:37 am
by warhead052
Do you have a capacitor from an air conditioning unit? Read the red label, "No start without starting device". Usually means you need a capacitor, or the thermostat.

Posted: Thu May 26, 2011 10:45 am
by qwerty
Capicators are for high voltage discharge, i don't think that's what he's looking for.
Anyway, not good with circuits so i can't help you here.

Posted: Thu May 26, 2011 11:35 am
by Technician1002
Some compressors only use the starting relay. As mentioned above, an external capacitor may be required. That is an old compressor. It used R12 which has been banned in most of the world for more than a decade.

Posted: Thu May 26, 2011 11:58 am
by pipeboyswe
Thanks dewey-1!!! Now it works!!! HP here i come :D now i got 3compressors working :D

Posted: Thu May 26, 2011 11:59 am
by pipeboyswe
dewey-1 wrote:You need a wire from the C terminal to L terminal.
This will simulate the thermostat switch.

Posted: Thu May 26, 2011 2:39 pm
by Technician1002
The wiring diagram was definitely needed. The connection between the L and C terminals was needed to bypass the thermostat.

With 4 compressors are you planning a 2 stage compressor? 3 in parallel as the first stage and one second stage?

Posted: Thu May 26, 2011 2:59 pm
by warhead052
qwerty wrote:Capicators are for high voltage discharge, i don't think that's what he's looking for.
Anyway, not good with circuits so i can't help you here.
High voltage discharge? I don't think so. I am not trying to say I know more than you, but I read in both a manual and online, plus heard from an ac repair tech, that capacitors are used for kick starting compressors. They are used to keep them from over working them selves and burning up faster.

Posted: Thu May 26, 2011 11:49 pm
by pipeboyswe
With 2 stage do you mean 1 compressor pumping air to The other 2 compressors? I know nothing of 2stage compressors. I was thinking to just connect all 3 to a x looking pipe and then straight to The Gun by a hose?

Posted: Fri May 27, 2011 12:04 am
by Technician1002
2 stage would be 3 in parallel feeding into the 4th.

It provides higher volume at higher pressure then simply paralleling a couple.
The first stage would provide about 80 PSI into the second stage with all 4 running.

If you need high volume instead of high pressure, just run them in parallel.

Posted: Fri May 27, 2011 12:21 am
by pipeboyswe
Im thinking of The maximum of 500psi And fairly fast filling times (300-400cm3) what should i go for??