Troubleshooting guide

Vent Termination Restrictor Usage for 40,000 Btu Power Vent Models
This bulletin will simplify vent termination restrictor usage for the 40,000 Btu power vent models and
allowable venting distances.
Power vent models, 40,000 Btu, manufactured prior to November 2004 (serial number K04) are
shipped with a vent kit that includes a 2" restrictor (1 ¾” inside opening) and 2” tee. These kits are
used for 2’ vent installations up to 33 equivalent (not to exceed 33 feet) feet of vent pipe (2” restrictor
is not needed if the vent run is longer than 33 equivalent feet) and a 3” restrictor and 45 degree elbow
for 3" vent installations of any vent length (up to the maximum distance of 38 equivalent feet). These
restrictors are to be installed in the vent termination tee or elbow if the vent is less than distances
listed above.
In November 2004 (serial number L04), the 2” restrictor (in the old vent kit) was replaced with a new
2" restrictor (1 ¼” inside opening) and the 3” restrictor was dropped from the kit. The venting distance
requiring the use of the restrictor was reduced to 20 feet or less with this change. This means that if
the vent distance is greater than 20 feet the restrictor is not needed. The series numbers (100 &
101) did not change with the revision to these kits. However, the termination tee that we have been
buying/using, since November 2004 has the 2” restrictor installed in the tee. If the vent length is more
than 20 feet the 2” restrictor in not needed and the restrictor must be removed from the tee or the
pressure switch will not make and the heater will not operate.
The restrictor’s affect is resistance or restriction and on short vent runs this helps maintain energy
factors. If used on longer vent runs (2” pipe over 20 feet), it adds too much restriction and the
pressure switch will not let the heater operate.
With all of that said, we are about to switch to a new series of power vent models (series 102 & 103)
that will not use a restrictor in the vent termination. You should start seeing this new series of powe
r
vent models by month end, as inventory levels begin to diminish. The new heaters will have different
blower, baffle and burner assembly (no NOx screen on the burner).
No.: ARGPN0305N
Date: March 18, 2005