Robertshaw SLIMZONE ENVIRONMENTAL MODULE - Manual (Page 10)

which is connected to the ductwork by means of a coiled 8' (2.4m) length of 1/8" (3.2mm)
PVC tubing. The length of the tubing provides protection from fluctuations in pressure and
temperature of air in the tube that may adversely affect the readings. Air feeds through the
tubing under pressure to the sensor.
CAUTION: DO NOT CUT OR SHORTEN THE PRESSURE SENSOR TUBING. IT
MAY BE LENGTHENED IF REQUIRED. USE 1/8" NONCOLLAPSIBLE TUBING.
The module will use the static pressure in the ductwork when all zones are open, fan is on,
and the bypass damper is closed as the nominal pressure of the system. Zone dampers open-
ing and closing cause changes in pressure in the ductwork. The SZEM module will respond
to these changes by opening or closing the bypass damper to return the static pressure to
nominal.
PRESSURE PROBE INSTALLATION
Drill a 1/4"(4mm) hole into the ductwork close to the module, at a recommended distance of
3' to 6' (1m-1.8m) downstream from the bypass damper. Push the end of the tube with the
probe and fastener into the hole until the fastener touches the ductwork (Page 7 – Detail 8).
Secure the fastener using the #8 sheet metal screw provided with the probe. Connect the
opposite end of the tube to the upper nipple of the SZEM module’s pressure sensor (Page 6 –
Detail 1).
BYPASS DAMPER INSTALLATION
The bypass damper must be installed in the main supply plenum in a straight section of equal
duct size. The bypass air may be discharged into the return air plenum or above the ceiling if
this area is used as a common return.
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