COMPRESSOR COMMERCIAL EMBRACO - NJ9226GK 1&1/8HP R404 (M/HBP)
A point of note, this compressor is rated as a 1&1/8 HP Commercial compressor, If you are really in the need and cannot get a correct replacement compressor, then also check out the specs on a 1&1/4 HP Commercial Compressor. The 1&1/4 Compressor is about 12 % bigger than a 1&1/8 HP compressor and many times the Condenser is slightly overrated and can accept this compressor
Click Here to make sure you have chosen the correct Compressor How to Test A Commercial Single phase (220 Volt) Refrigeration Compressor
Some Basics First
These Refrigeration Compressor have a Starting Capacitor (Normally between 60 and 80 uf (Micro-farads )
Unplug the refrigerator or turn off the breaker that powers it. Since you will have to get to the inside of the condenser unit of the refrigerator anyway, I would recommend you unplug it
On the side of the condenser unit you should see the terminal box with wires coming out of it. Remove the cover from this box. The cover will be held in place by either screws or retaining clips.
With the cover off, you should see the Start relay, and one or two Capacitors, one WILL be about 60 to 80 uf this is the Start Capacitor
If there is another Capacitor it will be in the range of 10 to 30 uf this is a Running Capacitor and has little to do with Stating the Compressor
There are a number of tests that you can perform to check if the Refrigeration compressor in faulty
Examine the Connections especially on the Compressor
The Smaller commercial compressor have their Starting relays on the compressor with the Start Capacitor outside the terminal box, proceed to do the normal checks on the Start and Clixton /Overload relay
Use the long-nose pliers to pull the wire connector off of the relay. Pull it off by gripping the connector, NOT the wire. Inspect both the connector and the relay for any signs of corrosion. If there are any, then you should replace the part.
Use the long-nose pliers to pull the wire connector off of the relay. Pull it off by gripping the connector, NOT the wire. Inspect both the connector and the relay for any signs of corrosion or heat damage. If there are any, then you should replace.
The bigger units have a starter box housing the Start Relay, and terminals for the condenser fan and Pressure switch
Test the Start Capacitor.
Be Very Careful here you are working With Voltage and Capacitance you are in danger of Electrical shock if you are negligent
If you have a megger, Set it to 500 Volts
See if the Capacitor can hold a charge , wait a short while then short the terminals out , The Capacitor should Discharge in a reasonably load bang and Flash if the capacitor is healthy
A health Capacitor will charge and slowly indicate on the megger that the capacitor is Zero conductive at empty and Moves to infinite conductivity as the capacitor becomes charged
If the refrigeration compressor Fails to start up due to a short term mechanical error try increasing the valve of your micro-farads of the start compressor say to 100 or 120uf, this bang is normally adequate to get the a healthy but impaired compressor going again.
Test the RUN Capacitor
If you have a megger, Set it to 500 Volts
See if the Capacitor can hold a charge , wait a short while then short the terminals out , The Capacitor should Discharge with a lesser load bang and Flash if the capacitor is healthy. Remember that the run capacitor is a much smaller Capacitor than the Start Capacitor
A health Capacitor will charge and slowly indicate on the megger that the capacitor is Zero conductive at empty and Moves to infinite conductivity as the capacitor becomes charged
A faulty Run capacitor shows itself in the compressor drawing to many amps ( current to high) or a healthy compressor stalling for no reason
Winding Burnt to earth
Set your Multimeter to Max Ohms reading(You know, the one that wants to read if you just touch the Probe terminals) or Meggar to 500v .Touch one of the tester's probes to Earth or a copper pipe and leave it there. (Test the meter to make sure its set correctly) Then, use the other probe to touch first one then the other terminals and finally the last one.
The tester should display a reading of "zero" ohms or Clear reading for each test. The compressor is in Order
Any reading here indicates that the wiring is no longer insulated and touching earth. The compressor has to be failed
Winding Burnt Between Coils / Windings
On the Compressor you will see three terminal points randomly number them a,b,c or 1,2,3, or left, right, top, Whatever......
Set your Multimeter to read Ohms reading or set your Meggar to Ohms . (Test the meter to make sure its set correctly) Then, Set one probe to touch first one “a” or “1” or whatever Now leaving this probe on this terminal take the other probe and Test:
Ohm reading “a” to “b” = record reading a-b
Ohm Reading “a” to “c” = record reading a-c
NOW MOVE the Fixed probe to the Next terminal Say “b"
Ohm reading “b” to “c” = record reading b-c
You now have three Ohm readings
a-b =
a-c =
b-c =
Now some Rules
The highest reading MUST be equal to the other two reading ADDED together
The highest reading is a reference to two terminal (Say “b-c”) the terminal that is not mentioned in this reference (this case “a”) is the Common or the terminal that you connect the Clixton or Overload to
The Second highest Ohm reading is the Run terminal
The lowest Ohm Reading is the Start Terminal
Conclusions
If the Reading DO NOT balance then the windings are burnt between coils and compressor has to be failed
The reading must all be in the same ball park say 4.5.9 (4+5=9) or 12, 15, 27 (12+15=27) if not then the compressor is giving false reading and must be failed.
If you really clever and are sure of your Common, Start and Run terminals, you can try start the compressor manually by Connecting a Neutral to the common terminal, a jumper between Run and Start. Put power on then as the refrigeration compressor then as the compressor labours, remove the jumper leaving Line/Live on run and neutral on Common, the compressor should run very comfortably (Keep a close watch on your AMPS)
Compressor Seized
If you have done all the above tests and the compressor Passes, and still find that the Refrigeration Compressor Amps (Current) is to high or the compressor will not rotate then in all likelihood the compressor is seized or failing mechanically, her are the logical symptoms
Refrigeration Compressor runs for a short while before the clixton overload switched the compressor off, The compressor starts up after a short while and the cycle is repeated On /OFF (Short cycling)
The Refrigeration Compressor merely hums and does not run
The compressor runs drawing abnormally high current (Amps)
Compressor valves Inefficient
To test Refrigeration Compressor Suction Valves
Disconnect all pipework from the Hi-side / Discharge pipe of the Refrigeration Compressor
Connect your Refrigeration Gauge Low side Gauge to the Suction /Low-side of the compressor
Open all Valves on your Refrigeration Gauges
Start the refrigeration compressor
Close the Low side Valve on your Gauge and observe to what level of vacuum the Refrigeration Compressor pulls the Gauge.
A good compressor will pull the Gauges into a deep Vacuum , A Faulty Compressor will hardly be able to Draw a vacuum or even just get the Gauge down to Zero
To test Refrigeration Compressor Delivery / Hi Side / Discharge Valves
Be Very Careful in Performing this Test. Major injury and/ or Damage to equipment can Occur
Disconnect all Pipework from the Suction / Low -side of the compressor
Connect the HIGH SIDE GAUGE of your Refrigeration Gauges to the Hi Side / Discharge Side of the compressor
OPEN all Valves on your Refrigeration Gauges
Start the compressor
GENTLY close you Refrigeration gauge Valve to throttle the Delivery of the compressor WATCH the Gauge slowly climb as you slowly throttle the delivery
A good Compressor Discharge Valves will very quickly MAX you Gauge out.
A Refrigeration Compressor with burnt / bent or leaky valves will struggle to get the High side gauge to go to its Maximum reading