Heating - Trane BCHE Installation, Operation And Maintenance Manual

– The A A i i 2 2 b b parameter is higher than the A A i i 2 2 M M
parameter.
– The temperature is not in the dead-band between
the A A i i 2 2 b b parameter and the A A i i 2 2 M M parameter (in
this case, previous state will be retained).
• The customer thermostat is properly hooked up the
input strip 1TB3, and is requesting cooling input (V1)
based on the customer cooling setpoint being lower
than the space temperature.

Heating

In general, the (CSTI) changeover function will provide
heating if:
• A unit is factory-configured with a changeover coil
(cooling/heating) as the only coil or as the main coil
portion.
• SW3 on the CSTI adapter board is turned on, and the
F F p p r r v v parameter set to E E H H l l or E E h h f f s s to use the
changeover functions.
– E E h h l l parameter should be chosen if the unit has a
changeover coil without electric heat.
– E E h h F F s s parameter should be chosen if the unit has a
changeover coil with electric heat. Generally, this
will perform the same as the E E h h l l parameter but will
in addition, disable the heating function on electric
heat and on the changeover coil heat if there are
fan failures. The auxiliary heating coil valve will
continue to respond to customer heating requests.
• The motor control board has sensed that there is hot
water available on the supply/bypass line for the
changeover coil. In this case, "hot" water is determined
if:
– A 10K NTC thermistor (similar to Trane part number
X13790374010) is wired properly to the motor
control board, through the crossover cables and
CSTI adapter boards.
– The input impedance of the thermistor circuit must
be set correctly (the A A i i p p u u parameter should be set
to i i n n for CSTI units).
– The temperature sensed is higher than the A A i i 2 2 b b
parameter.
BCX-SVX002A-EN
– The Ai2b parameter is higher than the A A i i 2 2 M M
parameter.
– The temperature is not in the dead-band between
the A A i i 2 2 b b parameter and the A A i i 2 2 M M parameter (in
this case, previous state will be retained).
• The customer thermostat is properly hooked up the
input strip 1TB3, and is requesting heating input (V2)
based on the customer heating set point being higher
than the space temperature.
• The heating input on 1TB3 will drive the main
changeover coil IF conditions 1–4 are satisfied, but will
always drive the auxiliary coil valve (if present). Electric
heat will be locked out (where present) if hot water is
available since SW4 will be factory set to "ON" in these
units.
SW4 selects the electric heat lockout function, where we
will lock out the electric heat circuit based on either:
• The presence of hot water in the changeover coil
section (if the F F p p r r v v parameter is set to E E H H l l ).
• Abnormal behavior of the fan/s (if the F F p p r r v v parameter
is set to F F n n S S t t ).
• Or a combination of both the presence of hot water or
abnormal behavior of the fan/s (if the F F p p r r v v parameter
is set to E E H H F F s s ).
The preceding three examples depend on the inference of
the motor control board that hot water is present. In this
case, "hot" water is determined if:
• The temperature sensed is higher than the A A i i 2 2 b b
parameter.
• The A A i i 2 2 b b parameter is higher than the A A i i 2 2 M M
parameter.
• The temperature is not in the dead-band between the
A A i i 2 2 b b parameter and the A A i i 2 2 M M parameter (in this case,
previous state will be retained).
• The input impedance of the thermistor circuit must be
set correctly (the A A i i p p u u parameter should be set to i i n n
for CSTI units).
Installation - Controls
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