R-290 Compressor Start & Run Capacitor - Bunn Ultra NX Service & Repair Manual

SERVICE - RIGHT SIDE PANEL COMPONENTS
Compressor Start Capacitor
FIG. 40 START CAPACITOR
Location:
The Start and Run Capacitor are located right side,
up front between the start relay and power supply.
Right Panel Removal:
1. Loosen 2 right side panel screws on the under-
side of the machine.
2. Grab and lower the right panel while pulling the
bottom outward to remove panel.
3. Front panel will need to be removed to access
the nuts securing capacitors to the machine
frame.
See "Service Front Panel Components" on how
to remove Front Panel.
Test Procedures:
CAUTION: Start Capacitors having a bleed resistor
across the terminals will bleed off residual voltage
in a start capacitor after it has been removed from
a motor circuit after start up. Not all Start or Run
capacitors use bleed resistors.
The bleed resistor is used as a safety feature to
discharge or eliminate the possibility of a leftover
charge that could cause an electric shock if not
handled properly during servicing of the equipment.
IMPORTANT: Examine the Start capacitor for a
bleed resistor before testing the start capacitor with
a capacitance meter.
If the capacitor you are replacing had a bleed down
resistor, then make sure your replacement start
capacitor has one or you will need to test the old
resistor to make sure it is good before reinstalling it
across the replacement start capacitor not having one.
Typically a bleed resistor resistance value should
read somewhere between 10 to 20k Ohms.
Start Capacitor
1. Disconnect main power from the machine.
2. Use Multimeter with Capacitance Setting.
3. WARNING: Ensure the start capacitor is
discharged before disconnecting the start
capacitor wires from the machine and remove
start capacitor.
4. If a bleed resistor is parallel across the start
capacitor terminals, isolate bleed resistor from
capacitor terminals. See FIG. 41.
5. Look and take note of the micro Farads rating on
the side of the capacitor.
6. Set multimeter to read capacitance/micro Farads.
7. A non polarized capacitor, connect the multimeter
leads either way to the capacitor terminals.
NOTE: In case of polarized capacitor, connect
the red probe to the positive terminal of the
capacitor (generally, the longer lead) and the
black probe to the negative terminal (usually,
there will be a marking on the side).
8. The multimeter reading should be within the
rated value on the side of the start capacitor and/
or within the percentage tolerance. Usually the
tolerance is not more than +/- 10%.
9. If the multimeter reading is way far from the rated
value or out of the allowable percentage range,
replace start capacitor.
Start Capacitor Rating:
Ultra NX 120V Models:
RATING: 340-408 MFD 165 V 50/60HZ
Ultra NX 200-240V Models:
RATING: 108-130 MFD 330 VAC 50 HZ
FIG. 41 START CAPACITOR
57
Bleed
Resistor
continued >