35
Note: Accessory static pressure drop is based on
desired CFM and may not be actual static pressure
drop.
3. Add the total accessory static pressure drop (step 2) to
the duct external static pressure (step 1). The sum of
these two values represents the total system external
static pressure.
Using the Fan Performance Tables in the Service Facts, look
up the selected speed tap setting and match the measured
ESP to determine the approximate CFM.
If the required CFM is too low, (external static pressure is
high) do one or both of the following and repeat procedure:
a. Relieve supply and/or return duct static.
b. Change indoor fan speed tap to a higher value
If the required CFM is too high, (external static pressure is
low), do one or both of the following and repeat procedure:
a. Increase supply and/or return duct static.
b. Change indoor fan speed tap to a lower value.
Note: Minimum setting for units with Gas or Electric
Heat is 320 CFM per Ton. For 3 & 4 Ton Gas Heat
units operating in heating mode the heat speed set
cannot be lower than Speed Set 4.
4. To stop the SERVICE TEST, turn the main power discon-
nect switch to the "Off" position or proceed to the next
component start-up procedure.
Return Air Smoke Detector
The return air smoke detector is designed to shut off the unit
if smoke is sensed in the return air stream. Sampling the air-
flow entering the unit at the return air opening performs this
function.
In order for the smoke detector to properly sense smoke in
the return air stream, the air velocity entering the unit must
be between 500 and 4000 feet per minute. Equipment cov-
ered in this manual will develop an airflow velocity that falls
within these limits over the entire airflow range specified in
the evaporator fan performance tables.
There are certain models however, if operated at low air-
flow, will not develop an airflow velocity that falls within the
required 500 to 4000 feet per minute range. For these mod-
els, the design airflow shall be greater than or equal to the
minimum CFM specified in the table provided below. Failure
to follow these instructions will prevent the smoke detector
from performing its design function.
Economizer Start-Up
ReliaTel Control
Using the Service Test Guide in Table 6, momentarily jump
across the Test 1 & Test 2 terminals on LTB1 one time to
start the Minimum Ventilation Test.
Electro Mechanical Control
Using the Service Test Guide perform the proper test mode
connections.
Start-Up
1. Set the minimum position setpoint for the economizer to the
required percentage of minimum ventilation using the
setpoint potentiometer located on the Economizer Con-
trol (ECA).
The economizer will drive to its minimum position
setpoint, exhaust fans (if applicable) may start at random,
and the supply fan will start when the SERVICE TEST is
initiated.
WARNING
Rotating Components!
During installation, testing, servicing and troubleshooting
of this product it may be necessary to measure the
speed of rotating components. Have a qualified or li-
censed service individual who has been properly trained
in handling exposed rotating components, perform these
tasks. Failure to follow all safety precautions when ex-
posed to rotating components could result in death or se-
rious injury.
The Exhaust Fan will start anytime the economizer damper
position is equal to or greater than the exhaust fan setpoint.
2. Verify that the dampers stroked to the minimum position.
ReliaTel Control
Momentarily jump across the Test 1 & Test 2 terminals on
LTB1 one additional time if continuing from previous com-
ponent start-up or until the desired start-up component Test
is started.
Electro Mechanical Control
Using the Service Test Guide perform the proper test mode
connections.
3. Verify that the dampers stroked to the full open position.
4. To stop the SERVICE TEST, turn the main power discon-
nect switch to the “Off” position or proceed to the next
component start-up procedure. Remove electro mechani-
cal test mode connections (if applicable).
Compressor Start-Up
1. Attach a set of service gauges onto the suction and dis-
charge gauge ports for each circuit. Refer to the refriger-
ant circuit illustration in the Service Facts.
ReliaTel Control
Momentarily jump across the Test 1 & Test 2 terminals on
LTB1 one additional time if continuing from previous com-
ponent start-up or until the desired start-up component Test
is started.
Electro Mechanical Control
Using the Service Test Guide perform the proper test mode
connections.
Scroll Compressors
a. Once each compressor has started, verify that the rotation
is correct. If a scroll compressor is rotating backwards, it
will not pump and a loud rattling sound can be observed.