Maintenance; Cabinet Insulation - Lennox Merit CBX25UH Series Installation Instructions Manual

second heat sequencer can be connected with the first
sequencer to W1 on the thermostat. They may also be
connected to a second heating stage W2 on the
thermostat subbase.
EMERGENCY HEAT (HEATING HEAT PUMP)
If the selector switch on the thermostat is set to the
emergency heat position, the heat pump will be locked out
of the heating circuit, and all heating will be electric heat (if
applicable). A jumper should be placed between W2 and E
on the thermostat subbase so that the electric heat control
will transfer to the first‐stage heat on the thermostat. This
will allow the indoor blower to cycle on and off with the
electric heat when the fan switch is in the AUTO position.

Maintenance

IMPORTANT
Do not operate system without a filter. A filter is required
to protect the coil, blower, and internal parts from exces­
sive dirt and dust. The filter is placed in the return duct
by the installer.
S
Inspect air filters at least once a month and replace or
clean as required. Dirty filters are the most common
cause of inadequate heating or cooling performance.
S
Replace disposable filters. Cleanable filters can be
cleaned by soaking in mild detergent and rinsing with
cold water.
S
Install new/clean filters with the arrows on the side
pointing in the direction of airflow. Do not replace a
cleanable (high velocity) filter with a disposable (low
velocity) filter unless return air system is properly sized
for it.
S
If water should start coming from the secondary drain
line, a problem exists which should be investigated
and corrected. Contact a qualified service technician.

Cabinet Insulation

IMPORTANT
DAMAGED INSULATION MUST BE REPAIRED OR
REPLACED before the unit is put back into operation. In­
sulation loses its insulating value when wet, damaged,
separated or torn.
Matt‐ or foil-faced insulation is installed in indoor
equipment to provide a barrier between outside air
conditions (surrounding
humidity) and the varying conditions inside the unit. If the
insulation barrier is damaged (wet, ripped, torn or
separated from the cabinet walls), the surrounding
ambient air will affect the inside surface temperature of the
cabinet. The temperature/humidity difference between the
inside and outside of the cabinet can cause condensation
on the inside or outside of the cabinet which leads to sheet
metal corrosion and subsequently, component failure.
REPAIRING DAMAGED INSULATION
Areas of condensation on the cabinet surface are an
indication that the insulation is in need of repair.
If the insulation in need of repair is otherwise in good
condition, the insulation should be cut in an X pattern,
peeled open, glued with an appropriate all-purpose glue
and placed back against the cabinet surface, being careful
to not overly compress the insulation so the insulation can
retain its original thickness. If such repair is not possible,
replace the insulation. If using foil‐faced insulation, any
cut, tear, or separations in the insulation surface must be
taped with a similar foil-faced tape.
1. CUT INSULATION IN X PATTERN
2. APPLY GLUE
3. PRESS GLUED TABS AGAINST CABINET
Figure 15. Repairing Insulation
Page 13
ambient temperature
GLUE -make sure there is
full coverage of glue on the
metal or insulation so there
are no areas where air
pockets may form which
can lead to sweating.
CBX25UH SERIES
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