50 MCP15-500.7
Hot Water Heat Coil Maintenance
If the unit is supplied with a factory installed hot water heat coil,
check the following:
1. Periodically, inspect the coils for signs of corrosion and
leaks. Repair and replacement of the coil and the
connecting piping, valves, etc., must be performed as
needed by a qualified technician.
2. For cleaning the external surface of the coil and fins
with compressed air and/or vacuum: The coil can
remain in the unit or be removed. Use compressed air
blown into the leaving air side of the coil and/or vacuum
from the entering air side of the coil to avoid pushing
foreign material further into the coil.
3. For cleaning the external surface of the coil and fins
with a cleaning solution: The coil must be removed from
the unit. Caution should be exercised in selecting the
cleaning solution as well as the cleaning equipment.
Improper selection can result in damage to the coil and/or
health hazards. Cleaning solutions must not be corrosive or
cause damage to copper tube/aluminum fin coils. Be sure
to carefully read and follow the cleaning fluid
manufacturer’s recommendations before using any
cleaning fluid.
4. Maintain the circulated fluid free of sediment, corrosive
products and biological contaminants. Periodic testing of
the fluid followed by any necessary corrective measures
along with maintaining adequate fluid velocities and proper
filtering of the fluid is required.
Hot Water Freeze Stat
If the unit is supplied with a factory installed hot water coil
freeze stat, check the following:
1. Disconnect the control wiring from the freeze stat terminals.
2. Remove the screws holding the freeze stat side access
panel. Refer to Figure 50.1.
Figure 50.1 - Optional Factory Installed Hot Water
Coil Freeze Stat
3. Slide the freeze stat assembly out.
4. Examine the freeze stat capilary for cleanliness and/or
obstructions as necessary. Ensure the capillary has no
kinks or breaks (replace if either of these conditions is
present).
5. Replace the freeze stat assembly in reverse order. In
replacing the assembly, be certain that the capillary support
frame is properly located and supported. Do not force the
side access panel. It will not fit if the frame is not properly
aligned.
6. Reconnect the control wiring to the freeze stat terminals.
Energy Recovery Exhaust Assembly
If the unit is equipped with a Modine supplied Energy Recovery
Exhaust section, check the following:
1. The energy recovery wheel drive belt is subject to natural
stretching which may affect wheel rotation and energy
recovery performance. The belt should be checked
periodically, especially within the first 400 hours of
operation. If too loose, the belt must be shortened by
removing the belt from the drive motor pulley, remove the
belt linkage using a small Phillips head screwdriver, cut the
belt to the required length, and reattach the belt linkage
and tighten.
2. The bearings are permanently lubricated and under normal
operating conditions maintenance is not required.
3. The wheel is to be checked for cleanliness. In most cases,
the counterflow airflow will allow the rotary wheel to self-
clean itself of contaminants that may adhere to the surface
of the wheel. In situations where self-cleaning is not
sufficient, the wheel can be cleaned with compressed air or
high pressure water (room temperature water only). To
clean the wheel, slide the wheel housing out of the unit
casing. Apply the air or water jet evenly and a right angles
to the wheel, being careful not to get any water on the
inside of the unit casing. Use care not to damage the wheel
physically and do not use chemicals.
4. Check wheel to housing seals and replace if worn.
Energy Recovery Wheel Electric Preheat
When providing annual maintenance for the electric preheat
(if equipped), keep the unit free from dust, dirt, grease and
foreign matter. Pay particular attention to:
1. The heating elements should be checked annually for
cracks and discoloration. If a crack is detected, the heating
elements should be replaced before the unit is put back
into service. If the elements are dark gray, airflow across
the heating elements should be checked to ensure that a
blockage has not occurred or the blower is operating
properly.
2. The electrical connections should be checked annually for
general cleanliness and tightness.
3. The controls should be checked to ensure that the unit is
operating properly.
Repeat Start-Up Procedure
Once complete, repeat applicable Start-Up Procedure steps as
shown starting on page 16.
MAINTENANCE - CONTINUED
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