Selection Of Auxiliary Heater - York IDH072B21S Series Installation And Maintenance Manual

5.7.1 Selection of Auxiliary Heater

Auxiliary heater for connection can only be duct heater type.
When using the auxiliary heater, auxiliary heater capacity must be properly selected. Otherwise, fire may
result from abnormal heating of heater. Select the allowable auxiliary heater capacity by following the
procedure below.
(1) Confirmation of Actual Airflow Volume
Indoor unit is restricted to the following fan speeds during the auxiliary heater ON and does not
correspond to the wired controller setting.
Confirm the actual airflow volume of the switched fan speed from the fan performance curves
in Section 10.
Be sure to design the duct arrangement so that the actual airflow volume does not exceed
the upper limit.
If the actual airflow volume exceeds the upper limit, unwanted noise may occur.
(2) Auxiliary Heater Capacity Selection
Select auxiliary heater capacity with minimum airflow volume requirement smaller than actual airflow
volume of indoor unit confirmed in step (1). When the minimum airflow volume requirement for the
auxiliary heater is greater than actual airflow volume of indoor unit confirmed in step (1) then failure of
indoor unit or fire may result from over heating of heater.
Depending on the temperature setting of the wired controller the maximum air outlet temperature of
indoor unit becomes approximately 122
requirements for the auxiliary heater.
Usage conditions such as minimum airflow volume, temperature range (maximum air inlet temperature)
for the auxiliary heater differs by heater manufacturer.
Be sure to follow the usage conditions when selecting the auxiliary heater capacity from the heater
manufacturer.
Maximum allowable heater capacity is different depending on indoor unit model.
If cold draft is a problem then select a larger heater capacity within the allowable capacity range.
If cold draft during defrost is a problem then change the optional function L9 to "01" to turn off both
heater and fan operation during defrost.
Depending on the Function Setting the heater and fan is turned off for approximately three minutes at
defrost recovery.
14
Wired Controller Setting
Low
Medium
High
o o
F (50 C) and may exceed the maximum air inlet temperature
NOTICE
Fan Speed
High
High
High
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