Reznor EXUB Unit Installation Manual - Manual (Page 12)

12
Regular inspection, based on a schedule determined by the amount of dirt in the atmosphere, assures
maximum operating economy and heating capacity.
Annual Inspection (before each heating season)
1. Check all terminal connections and electrical conductors for damage, looseness, defects, fraying, etc. and
replace or tighten where applicable.
2. Inspect contactor contacts. If badly pitted, burned or welded shut, replace with factory supplied contactor. It
is recommended that the contactor be replaced every three (3) years.
3. Inspect thermal delay fuses. Fuse rating and type are printed on circuit board. Correct fuse must be in the
“ACTIVE” fuse clip. An extra fuse should be stored in the clips marked “SPARE”.
4. Check for fluid leakage from heat-exchanger. The heat exchanger is filled with a mixture of water and inhib-
ited ethylene glycol, which is poisonous, and is factory vacuum-sealed. If fluid leakage occurs, remove
heater from service and have the heat-exchanger replaced by a factory replacement unit. Refer to “Repair
and Replacement” section for complete details. Do not attempt to loosen or tighten the vacuum plug or
pressure relief device. A loss of vacuum could cause nuisance tripping of the thermal cutouts or high
pressures which will cause the relief device to actuate with an accompanying loss of fluid.
5. Check all explosion-proof conduit and fittings. Replace damaged components. All threaded conduit
connections must have a minimum 5 turns of engagement. Taper threaded connections must be at least
hand tight. Inside of enclosures must be clean, dry, and free from any foreign materials. Enclosure covers
must also be completely on and tight.
6. Check electrical resistance on all load side legs. Reading should be balanced (± 5%).
7. Check motor shaft bearing play. Replace motor if play is excessive or if motor does not run quietly and
smoothly. Motor bearings are permanently lubricated.
8. Check fan blade. Replace immediately if cracked or damaged.
9. Check louvers. Louver screws should be tight. Louvers must not be set less than 30 degrees of the closed
position.
10. Check the tightness of all hardware. All nuts and bolts, including mounting hardware, must be tightened to
correct torque settings on Page 8.
11. Turn heater motor on for a minimum of 10 minutes. Crackling or pinging noises within heater during start-
up are normal. Check for air exiting heater through louvers and smooth running of motor.
Periodic Maintenance (before and as required during heating season)
1. Clean the following (remove dust using compressed air):
 Finned tubes
 Fan
 Fan Guard
 Motor
 Louvers
2. Check the following:
 Motor for smooth and quiet operation
 Louvers for proper angle and tightness
 All explosion-proof covers and fittings for tightness
 Contactor for signs of wear or pitting
— WARNING! —
Heater should only be service by qualified personnel experienced in electrical work.
Disconnect unit heater from power supply before starting any service or repair work. Lock the disconnect
switch in the “OFF” (open) position and/or tag the switch to prevent unexpected power application.
Failure to follow these procedures may result in severe or fatal injury.
— Maintenance Program —