Trane FC Installation & Operation Manual page 32

Figure I-MR-3. Attach the changeover
sensor to the entering water pipe as shown
for changeover to work properly
Figure I-MR-4. Close-up view of the
changeover sensor
Figure I-MR-5. Manual coil air vent with set
screw
Figure I-MR-6. Manual coil air vent with
Shrader fitting
32
Installation
Automatic Electric Heat Lockout Switch
Two-pipe fan-coil units with auxiliary
electric heat have an automatic electric
heat lockout switch that disengages the
electric heat when hydronic heat enables.
If the unit has a factory piping package
and electric heat, the factory attaches the
switch to the supply water pipe. When
the lockout switch detects the supply
water temperature above 95°F, it
disengages the electric heat. This
eliminates electric heat and hydronic heat
working simultaneously.
If the fan-coil unit does not have a factory
piping package, the switch and coiled lead
wires ship inside the piping side end
panel. The installer should position the
lockout switch on the supply water line of
the unit by sliding its spring connector
over the pipe. See I-MR-7.
Venting the Hydronic Coil
The hydronic coil contains a vent, either
manual or automatic, to release air from
the unit. This vent is not sufficient for
venting the water piping system in the
building.
The coil air vent is on the piping side,
above the coil connections on the unit.
See Figure I-MR-5 and I-MR-6. Perform
the following steps to vent the coil after
installing the unit.
1. Pressurize the building piping system
with water and vent any trapped air at
system vents.
2. For units with manual air vents, back
the set screw out to expel air from the
unit and then re-tighten the set screw.
The automatic air vent should require no
adjustment for the coil to vent. However,
if the coil does not vent immediately,
unscrew the outer portion of the fitting to
expel air from the port.
If debris has become trapped in the vent,
completely remove the outer portion of
the fitting and clean.
mechanical
requirements
Figure I-MR-7. Electric heat lock out switch
installed
External Insulating Requirements
Insulate and vapor seal surfaces colder
than surrounding air dew-point a to
prevent unplanned condensation. Trane
recommends field-insulation of the
following areas to prevent potential
condensate problems:
1. Supply and return water piping
connections
2. Condensate drain lines and
connections
3. Fresh air intake duct connections
4. Discharge duct connections
5. Wall boxes
UNT-SVX07A-EN