SS-SVX10H-EN
45
For Thermostat Control
When the room thermostat system switch is positioned
at C
CO
OO
OL
L and the fan switch is at A
AU
UT
TO
O, the RTRM
energizes the compressor contactor, provided the high
and low pressure and the discharge temperature limit
controls are closed. When the contacts of the
compressor contactor close, operation of the
compressor and condenser fan begins. The evaporator
fan contactor also energizes on a call for cooling and
initiates evaporator fan operation. On units with dual
circuits, the second stage of cooling is initiated as a
result of the 2-stage thermostat calling for additional
cooling.
N
No
otte
e:: Irregular unit operation may occur when the unit
is controlled with a triac-switching thermostat.
Please review the approved thermostat vendor
list for all recommended relay-switching
thermostats.
Control Evaporator Fan Operation
When the fan selection switch is set to the A
AU
UT
TO
O
position, the RTRM energizes the evaporator fan relay
coil approximately 1 second after energizing the
compressor contactor coil in the cooling mode. In the
heating mode, the RTRM energizes the evaporator fan
relay coil approximately 1 second before energizing the
electric heat contactors.
The RTRM de-energizes the evaporator fan relay coil
approximately 60 seconds on dual compressor units
and 80 seconds on single compressor units after the
cooling requirement has been satisfied to enhance unit
efficiency. When the heating cycle is terminated, the
evaporator fan relay coil is de-energized at the same
time as the heater contactors. When the fan selection
switch is set to the O
ON
N position, the RTRM keeps the
evaporator fan relay coil energized for continuous fan
motor operation.
Control Heating Operation
Electric heat is factory disabled on all split system units
with ReliaTel control (jumper placed between J2-1 and
J2-2 RTRM inputs). To configure the unit for electric
heat, cut or remove the jumper wire between J2-1 and
J2-2 on the RTRM. All split system units with ReliaTel
control are also configured from the factory for only 1-
stage of electric heat (jumper placed between J1-3 and
J1-6 RTRM inputs). To configure the unit for 2-stages of
electric heat, cut or remove the jumper placed between
J1-3 and J1-6 RTRM inputs.
When the system switch is set to the H
HE
EA
AT
T position
and heating is required, the RTRM energizes the Heat 1
relay coil on the RTRM. When the Heat 1 relay contacts
close, the first stage electric heat contactor is
energized. If the first stage of electric heat cannot
satisfy the heating requirement, the RTRM energizes
the Heat 2 relay coil on the RTRM. When the Heat 2
relay contacts close, the second stage electric heat
contactor is energized. The first and second stages of
heat are cycled “
“O
On
n”
” and “
“O
Offff”
” as required to maintain
the zone.
