Figure 8: Duct Static Pressure Sensing Tubing
Installation
Installing Building Static Pressure Sensor Taps
If a unit has building static pressure control capability, you
must field install and connect static pressure taps to the static
pressure sensor SPS2 in the unit. This sensor is located at the
bottom of the main control panel next to SPS1.
Carefully locate and install the two static pressure sensing
taps. Improper location or installation of the sensor taps causes
unsatisfactory operation. Below are pressure tap location and
installation recommendations for both building envelope and
lab, or “space within a space” pressure control applications.
The installation must comply with local code requirements.
Building Pressurization Applications
1 .
Install a tee fitting with a leak-tight removable cap
in each tube near the sensor fitting. This facilitates
connecting a manometer or pressure gauge if testing is
required .
2 .
Locate the building pressure (high) tap in the area that
requires the closest control. Typically, this is a ground
level floor that has doors to the outside.
3 .
Locate the building tap so it is not influenced by any
source of moving air (velocity pressure). These sources
may include air diffusers or outside doors.
4 .
Route the building tap tube through the curb and feed
it into the unit through the knockout in the bottom of the
control panel (refer to
). Connect the 1/8" ID tube
to the (high) fitting for sensor SPS2.
5 .
Locate the reference pressure (low) tap on the roof.
Keep it away from the condenser fans, walls, or anything
else that may cause air turbulence. Mount it high
enough above the roof so it is not affected by snow. Not
connecting the reference tap to the sensor results in
unsatisfactory operation.
6 .
Use an outdoor static pressure tip (Dwyer A306 or
equivalent) to minimize the adverse effects of wind.
Place some type of screen over the sensor to keep out
insects. Loosely packed cotton works well.
7 .
Route the outdoor tap tube out of the main control panel
through a small field-cut opening in the upright. Seal the
penetration to prevent water from entering. Connect the
1/8" ID tube to the (low) fitting for sensor SPS2.
Discharge Air Temperature Sensor
The discharge air temperature sensor must be installed in the
discharge air duct, downstream of the rooftop unit. Locate the
sensor in a location that closely approximates the average
duct temperature. To avoid the effects of radiation, the sensor
should not be in the line-of-sight of a gas furnace or electric
heater. Generally, locate sensor in the center of a duct wall,
5′ – 10′ from unit opening to allow for air mixing. Do not mount
down stream of VAV boxes or other dampers.
Installation: Drill 7/8" diameter hole in duct, insert sensor probe
and secure plate to duct with 2 -#10 screws. Be sure to apply
gasket or silicone sealant to back of mounting plate prior to
screwing plate to the duct to create an air-tight seal.
Figure 9: Discharge Air Temperature Sensor
Installation
Roof
SPS1
Main Control Panel
Condenser Section
HI Line
LO Line
Remote Sense Point
To Sensor
HI Input
Pressure Sensing
Tubing
Tubing Extends
Through Approx. 3/16"
Rubber
Grommet
Ductwork
(Remote Location)
To Sensor
LO Input
CAUTION
Fragile sensor fittings .
If you must remove tubing
from a pressure sensor fitting, use care. Do not use
excessive force or wrench the tubing back and forth to
remove or the fitting can break off and damage sensor.
M
eChanICal
I
nsTallaTIon
www.DaikinApplied.com
11
IM 1125-6 • REBEL ROOFTOPS
DOT-ITB-21-8041-AC
FPID: 437300-3-7B-01