McQuay IM 487-4
105
Maintenance
Maintenance
Installation and maintenance must be performed only by
qualified personnel who are experienced with this type of
equipment and familiar with local codes and regulations.
Servicing Control Panel Components
Disconnect all electric power to the unit when servicing
control panel components. Before servicing, always inspect
units for multiple disconnects to ensure all power is removed
from the control panel and its components.
Planned Maintenance
Preventive maintenance is the best way to avoid unnecessary
expense and inconvenience. Have this system inspected at
regular intervals by a qualified service technician. The
required frequency of inspections depends upon the total
operating time and the indoor and outdoor environmental
conditions. Routine maintenance should cover the following
items:
•
Tighten all belts, wire connections, and setscrews.
•
Clean all mechanically or with cold water, if necessary.
Usually any fouling is only matted on the entering air face of
the coil and can be removed by brushing.
•
Lubricate the motor and fan shaft bearings.
•
Align or replace the belts as needed.
•
Clean or replace the filters as needed.
•
Check each circuit’s refrigerant sightglass when the circuit is
operating under steady-state, full load conditions. The
sightglass should then be full and clear. If it is not, check for
refrigerant leaks.
Note:
A partially full sight glass is not uncommon at part load
conditions.
•
Check for proper superheat.
•
Check for blockage of the condensate drain. Clean the
condensate pan as needed.
•
Check the power and control voltages.
•
Check the running amperage of all motors.
•
Check all operating temperatures and pressures.
•
Check and adjust all temperature and pressure controls as
needed.
•
Check and adjust all damper linkages as needed.
•
Check the operation of all safety controls.
•
Examine the gas furnace (see Bulletin No. IM 684 or
IM 685).
•
Lubricate the door latch mechanisms.
Unit Storage
Location
•
The McQuay Rooftop Airhandling Unit is an outdoor unit.
However, the schedule may dictate storage either on the
ground or in its final position at the site. If the unit is stored
on the ground, additional precautions should be taken as
follows:
•
Make sure that the unit is well supported along the length of
the base rail.
•
Make sure that the unit is level (no twists or uneven ground
surface).
•
Provide proper drainage around the unit to prevent flooding
of the equipment
•
Provide adequate protection from vandalism, mechanical
contact, etc.
•
Make sure all doors are securely closed.
•
If isolation dampers are provided, verify that they are
properly installed and fully closed to prevent the entry of
animals and debris through the supply and return air
openings.
•
Units without isolation dampers should be fitted with covers
over the supply and return air openings.
Preparation
Supply (and Return) fans
1
Move the motor base to check and lubricate slides and
leadscrews.
2
Remove the drive belts, tag them with the fan name and
unit serial number, and store them in a conditioned space
out of direct sunlight.
3
Once every two weeks, rotate the fan and motor shafts.
Mark the shaft positions first to make sure they stop in a
different position.
4
Depending on local climatic conditions, condensate may
collect on components inside the units. To prevent surface
rust and discoloration, spray all bare metal parts with a rust
WARNING
Moving machinery and electrical power hazards. Can cause
severe personal injury or death.
Disconnect and lock off all power before servicing equipment.
CAUTION
Sharp edges are inherent to sheet metal parts, screws, clips,
and similar items. May cause personal injury.
Exercise caution when servicing equipment.
WARNING
Hazardous voltage. Can cause severe injury or death.
Disconnect electric power before servicing equipment. More
than one disconnect may be required to de-energize the unit.
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