15
16 Circulator Blower
This air handler is equipped with a multi-speed circulator
blower. This blower provides ease in adjusting blower speeds.
The Specification Sheet applicable to your model provides an
airflow table, showing the relationship between airflow (CFM)
and external static pressure (E.S.P.), for the proper selection of
heating and cooling speeds. The heating blower speed is shipped
set at 21kW or 25kW, and the cooling blower speed is set at “D”.
These blower speeds should be adjusted by the installer to match
the installation requirements so as to provide the correct electric
heating CFM and correct cooling CFM.
Use the CFM LED (green) to obtain an approximate airflow
quantity. The green CFM LED blinks once for each 100 CFM of
airflow.
1. Determine the tonnage of the cooling system installed with
the air handler. If the cooling capacity is in BTU/hr divide it
by 12,000 to convert capacity to TONs.
Example:
Cooling Capacity of 30,000 BTU/hr.
30,000/12,000 = 2.5 Tons
2. Determine the proper airflow for the cooling system. Most
cooling systems are designed to work with airflows between
350 and 450 CFM per ton. Most manufacturers recommend
an airflow of about 400 CFM per ton.
Example
: 2.5 tons X 400 CFM per ton = 1000 CFM
The cooling system manufacturer’s instructions must be checked
for required airflow. Any electronic air cleaners or other devices
may require a specific airflow; consult installation instructions of
those devices for requirements.
3. Knowing the air handler model, locate the high stage
cooling airflow charts in the Specification Sheet applicable
to your model. Look up the cooling airflow determined in
step 2 and find the required cooling speed and adjustment
setting.
Example:
A DV31PTCC14 air handler installed with a 2.5
ton air conditioning system. The airflow needed is 1000
CFM. Looking at the cooling speed chart for DV31PTCC14,
find the airflow closest to 1000 CFM. A cooling airflow of
1000 CFM can be attained by setting the cooling speed to
“C” and the adjustment to “0” (no adjustment).
COM
TH
TR
DE
CAS
HUM
O
R
2
1
C
2
1
ST4
ST3
ST2
ST1
3A
C
Y2
24VAC
FUSE
W1
W2
R
C
G
W1
W2
Y1
3
2
Dip Switches
Green CFM LED
Seven Segment
LED
Auxiliary
Alarms
Communication Board
Figure 21
Содержание DV PTC 14 Series
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