Heating System Startup; Air Balancing - Daikin RDT-135c Installation And Maintenance Manual

Check, Test, and Start Procedures: Heating System Startup
If low oil level is accompanied by heavy foaming
Note:
visible in the oil sightglass, it is possible that excess
liquid refrigerant is returning to the compressor
depending on the rotation of the crank shaft. Check the
suction superheat and adjust the expansion valve for
10°F (–12°C) to 13°F (–11°C) of superheat. If proper
superheat is obtained, sightglass foaming is not a
concern.
For RCS/RFS applications in which the condensing section is
remote from the air handling section, consideration should
have been given to proper piping between the sections, as this
can affect the compressor oil level. Refer to the "ASHRAE
Handbooks" for more information on proper refrigeration
piping design and installation.

Heating System Startup

General
At the keypad, set the heating setpoints high enough so that
1
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.
Verify that the high ambient heat lockout temperature
3
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,
Bulletin No. 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 II 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.
104
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" on page 106. The return fan motors are
usually shipped with fixed pitch sheaves.
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.
The following should be performed as part of the air balancing
procedure:
Check the operating balance with the economizer dampers
1
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 II
controller's built-in, automatic capability. For complete
information on using this feature, see the "Return Fan
Airflow Control: Fan Tracking" section in Bulletin No.
OM 137, "MicroTech II Applied Rooftop Unit Controller."
When the final drive adjustments or changes are complete,
4
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.
Rotating parts can cause severe personal injury or death.
Replace all belt/fan guards that are temporarily removed for
service.
WARNING
WARNING
IM 738-2