Arzel AirBoss - Bypass Operation and Remedies; Bypass Operation with Zone Calls; Air Surging Noise Remedies; Fan Operation Issues Troubleshooting

6
(1) Determine Furnace manufacturers specified “Temperature Rise” on
Equipment Rating Label.
(2) Add 70 deg to the maximum temperature rise; Example- If the specified
temperature rise is “35 to 60 deg”, Add 70 deg (average return air
temperature) to the maximum 60 deg Rise. Your Htg LAT setting should
be 130 deg. If nuisance tripping occurs, raise the setting to eliminate
tripping without reaching the limit temperature of the furnace.
b) If coil is freezing up or LAT is cycling “Y1” off to often, check the following:
i) Oversized bypass duct depleting return air and lowering coil temperature.
(A bypass duct is used strictly to minimize excessive static pressure and is
a detriment to heat transfer across the coil)
ii) Set Cooling LAT set-point per the following guidelines
(1) Start with a setting of 42 deg and raise 2 deg at a time if DX Coil shows
signs of icing. Remember that it takes more than 30 min of run time to ice
up a coil. Because zoning increases the effectiveness of the a/c system it
will most likely satisfy the calling thermostat prior to icing the coil.
(2) Locate the LAT Sensor in the supply duct (not in the plenum), prior to any
trunk dampers and in a duct common to all zones. If you have to locate
the sensor in one side of a Teed duct, place it in the side with the Bypass
or smallest cooling Zone.
12) Bypass Operation and Remedies
a) Check Bypass operation with smallest zone calling and largest zone calling.
i) Bypass should only be open if air noise is an issue when the smallest zone is
calling for cooling with all other zone satisfied.
b) Air surging noise with smaller zone open.
i) Bypass most likely oversized, (Refer to Arzel Bypass Sizing Chart).
ii) If not present, install orifice in pressure tube feeding bypass solenoid valve in
panel. (Orifice available through Arzel Zoning Technology).
iii) If bypass is proven to be too large, install a volume damper in the duct and
reduce airflow until operation is satisfactory.
c) Fan Operation Issues
i) ICM Variable speed motor is ramping up and down.
(1) Bypass is possibly oversized and/or not properly adjusted
(a) Refer to Arzel Bypass Sizing chart, add volume damper to decrease
capacity.
(b) Adjust bypass to open only when air noise exceeds tolerable levels.
(2) Blower speed is set to high for system capacity
(a) Check and adjust CFM output of blower (400 cfm / ton).
If all else Fails, Call the Arzel Tech Support Hot Line
1-800-611-8312
www.arzelzoning.com