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Troubleshooting Chart
Note: These items should be checked by a qualified service technician only.
Trouble
8. Insufficient cooling capacity
(continued).
9. Too much cooling.
10. "Sweating"
11. Blowers won't operate
on Heat.
12. **Equipment is noisy.
13. Insufficient or no heat
IM 1068-2 / Page 24 of 28
Cause
d. Heat load in room exceeds capacity of equipment.
e. Windows and doors in room are open.
f. Compressor not pumping, indicated by:
1) Low wattage.
2) Condenser not warm, evaporator only partially cool, or not at all.
g. Restricted capillary tube or strainer, indicated by:
1) Frost on capillary tube or strainer.
2) Low wattage.
3) Condenser not warm.
4) Evaporator partially frosted, only partially cool, or not at all.
a. Thermostat set too low.
b. Defective thermostat.
a. Condensate drain from evaporator to condenser plugged.
b. Insulating seals on equipment damaged.
c. Evaporator blower motor not up to speed.
d. Evaporator blower incorrectly positioned.
a. No power.
b. Heat is off (equipment with heat fan lockout).
c. Faulty push-button switch.
d. Loose connections at push-button switch.
e. Thermostat set too low.
a. Blower rubbing against enclosure.
b. Blower motor bearings are dry.
c. Loose blower hold-down nuts on motor-bracket assembly.
d. Refrigerant absorbed in compressor oil after extended shutdown.
e. Equipment improperly installed.
f. Damper solenoid hums.
g. Loose terminal box cover on side of compressor.
h. Loose electrical components.
i. Copper tubing vibrating.
j. Harmonics.
k. Loose sheet metal parts.
a. No steam or hot water being applied.
b. No Power.
c. Faulty push-button switch.
d. Loose connection at push-button switch.
e. Thermostat set too high.
f. Thermostat faulty.
g. No power output on transformer secondary.
h. In-operative valve.
1) Steam valve normally closed.
2) Hot water valve normally closed.
Cure
d. Refer to original load calculations; recalculate heat load.
e. Close them.
f. * Ship cooling chassis prepaid to nearest McQuay authorized
warranty station.
g. * Ship cooling chassis prepaid to nearest McQuay authorized war-
ranty station.
a. Adjust.
b. Replace.
a. Remove obstructions to water flow.
b. Adjust or replace.
c. Check for correct voltage. Oil motor if necessary.
d. Adjust.
a. Correct as in #1.
b. Open heat valve or turn on heating system.
c. Replace.
d. Tighten.
e. Adjust – rotate control knob to "Warmer".
a. Adjust fan position on motor shaft to reposition fan motor bracket
assembly.
b. Lubricate with SAE #19 oil or replace motor.
c. Align blower assembly and tighten nuts.
d. Noise will disappear after equipment runs awhile.
e. Make necessary adjustments to components.
f. Check for proper adjustment. Apply silicone oil or grease to gap
between solenoid and armature.
g. Tighten.
h. Fasten securely.
I. Adjust by bending or applying tape.
j. Occasionally equipment will have noisy operation for no apparent
reason. Inspect ion has revealed no loose components that might
be the source of the noise. Due to the action of the compressor, it
is possible to have internal noise develop if the refrigerant tubing
has become bent even slightly. To distinguish this condition from
the simple rattle producing vibration caused by loose screws, nuts,
and other components, grasp the refrigerant tubing at various points
throughout the system until a point is found where the noise is
eliminated or reduced. Bend the copper tubing very gently until the
noise disappears.
k. Tighten.
a. Contact building management.
b. Check power supply line fuses, circuit breakers. Blow fuses would
indicate circuit overloading, a short circuit, or a grounded condition in
the circuit.
c. Replace.
d. Replace wire or tighten.
e. Adjust – rotate knob to "Warm".
f. Replace.
g. Replace.
h.
1) Temporarily lock valve open; replace.
2) Replace.
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