INSTALLATION GUIDE
24
Mechanical Installation (cont.)
INSTALLATION OF STACK PROBE FOR
Draft Switch (cont.):
For the Draft Switch to function properly, the probe
must be
placed in a location that can produce at
least 0.05 in/WC in the stack. In order to produce an
accurate pressure reading, the tip of the probe must
be mounted flush with the inside of the stack wall
(it should never extend more than 1/16” beyond the
wall). For a double walled stack, the tip should be
flush with the inner most wall.
To mount the probe, drill a clearance hole through the
stack wall(s). Insert the probe and attach the bracket
to the stack using (2) customer provided self-tapping
machine screws. Tighten the end cap to compress
the ferrule and permanently install the stack probe.
Attach the supplied silicon tubing at the other end of
the probe.
Draft Switch
STACK PROBE
(ALTERNATE LOCATION)
FROM APPLIANCE
VENTING TO
EXTERIOR
STACK PROBE
PDS1
A
V
A
A
V
For all installations, the stack probe must be placed so the flow through the stack is perpendicular to the
tip of the probe. Locate the probe at least the distance “A” away from any elbows or tees in the stack. The
distance “A” is designed as at least three (3) vent diameters; A ≥ 3 *V (see figure below). To prevent con
-
densation from entering the probe or Draft Switch when installed on a horizontal stack, the probe must be
installed above the centerline of the stack. For fireplace installations, the stack probe should be installed as
close to the exhaust fan as possible.
BL_ST_INSTL_RevB_4.08.19
