98 McQuay IM 987
Check, Test, and Start Procedures
Heating System Startup
General
1 At the keypad, set the heating setpoints high enough so
that the controller calls for heating.Adjust the value in
Temperature \ Zone Heating \ Occ Htg Spt= above the
temperature shown in Temperature \ Zone Heating \
Control Temp=. In addition, on DAC units, adjust the
value in Temperature \ Discharge Heating \ DAT Htg
Spt= above the temperature shown in Temperature \
Discharge Heating \ Disch Air=.
2 Place the unit into heating mode through the keypad
menu System Summary \ System \ Ctrl Mode= Heat Only.
3 Verify that the high ambient heat lockout temperature
setpoint, Temperature \ Zone Heating \ OATHtg Lock= is
set above the current outside air temperature (shown in
System Summary \ Temperatures \ OA Temp=).
Gas Furnace
Refer to the “Start-up and Operating Procedures” section of
the Forced Draft Gas Fired Furnace Installation Manual, IM
684 or IM 685. Perform the start-up procedures given in it.
Electric Heat
Turn the electric heat switch HS1 to ON. The electric heaters
should energize. If the unit has multistage electric heat, the
MicroTech III Auxiliary Control board EHB1 should energize
the heaters in successive stages. The rate of staging is set in
keypad menu Setup/Service \ Heating Setup \ Stage Time=. The
default value of 5 min”can be adjusted from 2 to 60 minutes.
Steam Heat
The steam valve actuator should open the valve. The steam
valve is open when the valve stem is up. If the unit loses
power, the spring in the actuator should drive the valve wide
open. Check this by opening system switch S1.
Hot Water Heat
The hot water valve actuator should open the valve to the coil.
The three-way hot water valve is open to the coil when the
valve stem is down. If the unit loses power, the spring in the
actuator should drive the valve wide open to the coil. Check
this by opening system switch S1.
Air Balancing
Air balancing should be performed by a qualified air balancing
technician. Note that the supply fan motors are usually shipped
with variable pitch sheaves which are typically set at the low
end of the drive’s fan rpm range. See "Mounting and Adjusting
Motor Sheaves"‚ page 100. The return fan motors are usually
shipped with fixed pitch sheaves.
The following should be performed as part of the air balancing
procedure:
1 Check the operating balance with the economizer
dampers positioned for both full outdoor air and
minimum outdoor air.
2 Verify that the total airflow will never be less than that
required for operation of the electric heaters or gas
furnace.
3 For VAV units that have fan tracking control, adjust the
supply/return fan balance by using the MicroTech III
controller's built-in, automatic capability. For complete
information on using this feature, see OM 920
“MicroTech III® Unit Controller for Applied Rooftop
and Self-Contained Systems”
4 When the final drive adjustments or changes are
complete, check the current draw of the supply and
return fan motors. The amperage must not exceed the
service factor stamped on the motor nameplate.
5 Upon completion of the air balance, replace variable
pitch motor sheaves (if any) with comparably sized fixed
pitch sheaves. A fixed pitch sheave will reduce vibration
and provide longer belt and bearing life.
WARNING
Moving machinery hazard. Can cause severe personal injury
or death.
Do not use a mechanically driven tachometer to measure the
speed of return fans on this fan arrangement. Use a strobe
tachometer.
WARNING
Rotating parts can cause severe personal injury or death.
Replace all belt/fan guards that are temporarily removed for
service.
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