Installation Instructions

Installation Instructions
Document No. 129-495
October 6, 2009
Standard Duct Averaging Sensor
Long Bendable Probe, RTD and NTC
Thermistor
Item Number 129-495, Rev. AA Page 1 of 4
Product Description
The Duct Averaging Temperature Sensor assembly
senses the average air temperature in ductwork where
mixing baffles are not provided or where stratification
occurs. Each sensor assembly mounts on sheet metal
ducts.
Contents
• Long, bendable averaging element
• Electrical box for wiring connections
Product Number
QAM20xx types 8-foot, 16-foot, or 24-foot length
(2 m, 5 m or 7 m)
Warning/Caution Notations
CAUTION:
Equipment damage or loss of
data may occur if you do not
follow a procedure as
specified.
Required Tools
• Wire cutters
• Small flat-blade screwdriver
• Medium flat-blade screwdriver
• Four No. 10 × 1-inch sheet metal screws
• Electric drill and 1/2-inch and 7/8-inch drill bits
• No. 27 drill bit for screw holes
• Wire ties suitable for service in the ductwork
Expected Installation Time
2.5 hours
Recommended Sensing Element
Arrangements
Figures 1, 2 and 3 show the sensing element
arrangements. They provide the fastest response
when the element is exposed to cold temperatures.
Figure 1 shows the most practical mounting
arrangement; it does not require inside access to the
duct. The other sensing element arrangements require
inside access to the duct.
Mounting Hardware
Required for limited access duct mounting, Option A
(Figure 1):
• Two mounting flanges (P/N 808-412).
• 16 No. 10 × 1-inch sheet metal screws.
• Tin snips.
• Pre-cut and drilled 8-inch × 4-inch (200 mm ×
100 mm) piece of sheet metal.
• Support rod of 3/8-inch OD copper or suitable
equivalent, long enough to fit diagonally
across the duct.
Required for inside-access duct mounting, Option B
(Figures 2 and 3):
• Perforated steel hanger strap long enough to
traverse the duct at least twice.
• Four No. 10 × 1-inch sheet metal screws.
Prerequisites
• The signal wiring must be pulled to the
installation site and enclosed in 3/8-inch or
1/2-inch (13 mm) flexible conduit.
• For the mounting Option A, mount one
808-412 mounting flange and the sensor on
the 8 × 4-inch (200 mm × 100 mm) sheet
metal plate.
NOTE: Be sure that the screws are within the
6-inch × 2-inch (152 mm × 50 mm)
duct access hole area.