Unit Start-Up
40
RT-SVX23G-EN
b. Change indoor fan speed and repeat
Step 1
and
Step 2
.
•
To Increase Fan RPM; Loosen the pulley adjustment set
screw and turn sheave clockwise.
•
To Decrease Fan RPM; Loosen the pulley adjustment
set screw and turn sheave counterclockwise.
•
If the required CFM is too high, (external static
pressure is low causing motor HP output to be above
table value), change indoor fan speed and repeat
Step
1
and
Step 2
.
•
To stop the SERVICE TEST, turn the main power
disconnect switch to the "Off" position or proceed to
the next component start-up procedure.
ReliaTel™ Units with Direct Drive Indoor
Fan (7.5 to 10 Ton Units)
Much of the systems performance and reliability is closely
associated with, and dependent upon having the proper
airflow supplied both to the space that is being
conditioned and across the evaporator coil.The indoor fan
speed is changed by adjusting the voltage from the RTOM
Indoor Fan Speed output to the direct drive plenum fan. If
installed, before starting the SERVICE TEST disable the
Economizer by disconnecting the 4 pin power connector
located at the base of the Economizer Control (ECA).
Using the ServiceTest Guide in
Table 8, p. 38
, momentarily
jump across theTest 1 &Test 2 terminals on LTB1. Repeat
process until Service Test Mode is at Cool 2 (2-Steps of
Cooling Applications Only) or Cool 3 (3-Steps of Cooling
applications). The indoor motor shall be operating @
100%, to verify turn DA COOL_FAN SPD potentiometer full
clockwise, voltage should read ~7.5 Vdc across harness
test terminals. The unit schematic illustrates location for
measuring the indoor motor speed voltage.
Once the supply fan has started, determine the total
system airflow (CFM)
1.
Measure the DC voltage across harness test terminals.
Using the fan rpm table shown above, determine RPM
correlated to measured voltage.
2. If the required CFM is too low, (external static pressure
is high causing motor HP output to be below table
value),
a. Relieve supply and/or return duct static.
b. Change indoor fan speed and repeat
Step 1
and
Step 2
.
•
To Increase/Decrease Fan RPM turn DA COOL_FAN
SPD on the RTOM clockwise/counter-clockwise.
3. If the required CFM is too high, (external static
pressure is low causing motor HP output to be above
table value), change indoor fan speed and repeat
Step
1
and
Step 2
.
•
Stop the SERVICE TEST, turn the main power
disconnect switch to the “Off” position and reconnect
Economizer 4-pin power connector if disconnected for
this procedure.
•
Proceed to the next component start-up procedure.
Table 9.
RPM table
Potentiometer
Voltage
Motor RPM
Potentiometer
Voltage
Motor RPM
1.25
217
4.50
1061
1.50
312
4.75
1126
1.75
362
5.00
1191
2.00
427
5.25
1253
2.25
479
5.50
1315
2.50
543
5.75
1374
2.75
605
6.00
1432
3.00
668
6.25
1487
3.25
732
6.50
1539
3.50
797
6.75
1588
3.75
863
7.00
1633
4.00
929
7.25
1675
4.25
995
7.50
1700
Note:
Factory setting is 5V
Figure 42.
Plenum fan rpm label
