KAH Operation & Maintenance Guide
Page: 11 of 88
Krueger | 1401 N Plano Rd | Richardson, TX 75081 | 972.680.9136 | [email protected] | www.krueger-hvac.com
SECTION 2 - START-UP & OPERATION (CONTINUED)
Air Measuring at the Fan Inlets
•
COMETER is a probe attached to the fan bearing
support on Comefri Forward Curve fans from size 7 x
7 up to 18 x 18. The probe is located on the outboard
side of the housed fan assembly. The probe is piped to
the negative (-) port of a factory mounted transducer
on the fan wall. The positive (+) port is left open to the
fan section. Wiring is not provided to the transducer.
•
PIEZORING (PIEZOMETER) is a fitting or series of
fittings in the inlet cone(s) of housed fans larger than
18 x 18 and all sizes of Plenum fans that are combined
into a single connection piped to the negative (-) port
of a factory mounted transducer on the fan wall. The
positive (+) port is left open to the fan section. Wiring
is not provided to the transducer.
NOTE -
The fan manufacturer does not recommend
placement of the flow measuring probes inside
the fan inlet cone in the path of airflow. These
devices create disturbances and unpredictable
performance losses.
FIGURE 6 - HIGH AND LOW CONNECTIONS FOR AN
IN FAN AIR MONITORING SYSTEM
FIGURE 7 - PORT LOCATIONS FOR FAN MOUNTED
AIR MONITORING SYSTEM
High Port
Low Port
Air Measuring at Unit Outside Air Inlets
•
AMS-60 used on indoor air handlers usually measure
outside air. This can be provided with one or two pairs
of positive (+ or High) and negative (- or Low) pressure
tube connections. Connect (+) and (-) respectively to
the (+) and (-) ports of the transducer(s). Wiring and
transducer are not provided unless factory packaged
controls were selected.
Airflow Control Dampers
Many combinations of damper sizes are available to
control the flow. Mixing the return and outside air in the
AHU’s air inlet section may be supplied as follows:
•
100% outside air, 100% return air.
•
100% outside air, 0% return air.
•
0% outside air, 100% return air.
•
Economizer section - 100% outside air, 100% return
air, 100% exhaust air or mixed air.
Check the dampers, actuators, controls and linkage prior
to applying power to the operators, to make sure nothing
will obstruct the operation of the dampers.
Return air dampers may be closed for shipping. Loosen
the actuator or crank arm on the jackshaft, open the
dampers, and re-tighten the actuator or crank arm. The
field is responsible for adjustments.
Air Measuring Device Connections
Calculating Flow Rate
For a Piezoring:
CFM = k * √ΔP
ΔP = The differential in static pressure across the fan (in. w.g.)
k = See the following table
This assumes a standard air density of .075 lbs / cubic foot at
sea level.
For a Cometer:
CFM = k * √ΔPn
ΔP = The differential in static pressure across the fan (in. w.g.)
k = See the following table
n = See the following table
This assumes a standard air density of .075 lbs / cubic foot at
sea level.
NOTE -
Do not overdrive the damper actuators
because this may damage the dampers.
Exception: Actuators with over drive preset option.
