Carrier AERO 39MN Installation, Start-Up And Service Instructions Manual page 125

HUMIDIFIER INSTALLATION CHECKLIST — Ensure:
1. Humidifier is properly assembled with all discharge
slots facing the proper direction. (Multipipe systems
have the vertical slots in line with the manifolds, 90 de-
grees to the airflow.)
2. Humidifier headers are secured and level.
3. Humidifier upright discharge manifolds are plumb.
4. Valve and trap assembly is properly assembled and con-
nected to the humidifier header.
5. P-trap is installed on discharge of each header.
6. Steam feed line is properly run, sloped and connected to
the valve and trap assembly inlet.
7. Controls are properly wired.
HUMIDIFIER START-UP
1. Slowly open the steam isolation valve from the steam
supply line. You should be able to hear steam running
through the valve. Wait a few minutes for the steam to
heat up the entire line to the humidifier and for all con-
densate to clear through the trap.
2. Verify that the steam trap on the valve/trap assembly of
the humidifier is working properly — condensate dis-
charge line should be hot.
3. With air flowing in the duct or air handler, create a hu-
midification demand by increasing the humidity control
set point until it exceeds the actual humidity reading.
4. The valve on the humidifier should begin to open and
steam should enter the humidifier manifolds.
5. Initially most of the steam will condense as it heats the
manifolds. Ensure that the P-traps on the manifolds are
clear and running to drain without leaking steam.
NOTE: On first start-up, some steam may leak from the
P-traps on the manifolds if they have not been primed
(filled with water).
6. Steam should begin exiting the humidifier manifolds.
7. Return the humidity control set point to the desired
level.
COILS
Water Coil — Typical coil vents, drains, and lifting points are
shown in Fig. 62. Open the vent plug, partially turn on the
water supply until air is exhausted, and replace the vent plug.
Fully turn on the water supply.
Direct Expansion Coil — Charge with refrigerant. Refer to
Condensing Unit instructions. Refrigerant operating charge is
shown in Table 12, page 31.
Steam Coil
1. Generate steam in the steam main and open the supply
(gate) valve to the coil.
2. Thoroughly preheat the coil with steam before starting
fans, especially when inlet air temperature is below
freezing. If water hammer occurs, turn off fans until
condensate trapped in coils is reduced by heat and steam
pressure.
3. Ensure continuous-vent petcock is open; also check op-
eration of gate valves, control valve, and check valves.
4. After operating coil for 50 hours, check strainer and re-
move any foreign matter. Check traps and drip lines for
correct condensate removal. Where necessary, increase
the pitch of lines to increase condensate drainage. (Re-
check operation after 50 hours and repeat if necessary.)
INTEGRAL FACE AND BYPASS COIL START-UP — En-
sure that the damper operator allows the dampers to fully
close the face and reverses to fully close the bypass. Set the
thermostat so that the face opens and bypass closes when heat
is required.
On start-up, the steam or hot water supply will be fully ex-
panded prior to start of airflow. Allow time for all air to be
purged from the system and for the heating surface to fully
warm up in order to avoid heating lag.
Preheating a cold system will avoid excessive steam con-
densate loading at the start of operation of a steam heating
system. It also protects steam and hot water units against
freezing up when subject to sub-freezing air temperatures.
After preheating, fully open the dampers for full-face expo-
sure (bypass closed). Start airflow. Set thermostat for desired
air temperature.
ELECTRIC HEATERS
1. Check tightness of all electrical connections.
2. Remove heater circuit fuses.
3. Turn on power to activate transformer.
4. Start up base unit fans. Check airflow and switches. Re-
fer to base unit instructions as required.
5. Set thermostats so that heater contactors will operate.
6. Shut off unit power.
7. Reinstall fuses.
8. Turn on unit power and heater power.
GAS-FIRED FURNACES (DUCT AND RACK SYS-
TEM) — Refer to the wiring diagram and sequence of operation
documents included in the furnace section of the unit, or contact
your Carrier service representative for assistance with this infor-
mation, before attempting to place the single unit heater or rack
system into service.
The use and storage of gasoline or other flammable vapors
and liquids in open containers in the vicinity of this appli-
ance is hazardous and may result in fire or explosion.
Also, note the following points:
• The duct furnace(s) or rack system furnaces do not have a
pilot. They are equipped with a direct spark ignition device
that automatically lights the gas burner. Do not try to light
burners by hand.
• Before operating, leak test all gas piping up to heater gas
valve. See the section Gas Supply, Piping, and Connections
on page 116 (single unit) or page 120 (rack assembly). Smell
around the unit area for gas. Do not attempt to place heater in
operation until source of gas leak is identified and corrected.
• Do not attempt to operate unit if there is any indication that
any part or control has been underwater. Any control or com-
ponent that has been under water must be replaced prior to
attempting to start the unit.
• Use only hand force to push and turn the gas control knob to
the "ON" position. Never use tools. If knob does not operate
by hand, replace the gas valve before starting the unit.
If the gas control knob does not operate by hand, replace it
before starting the unit. Forcing or attempting to repair the
gas valve may result in fire or explosion.
Start-Up (Duct Furnace) — Follow these steps to start the gas-
fired duct furnace:
1. Turn thermostat or temperature controller to its lowest
setting.
2. Turn off gas supply at the manual shut-off valve.
3. Turn off power to the unit at the disconnect switch.
4. Remove access panel or open door to unit vestibule hous-
ing the gas heater.
5. Move gas control knob to "OFF" position.
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WARNING
WARNING