Fulton Pulse DWH (PDWH) Domestic Water Heater - Manual (Page 19)

Installation
17-PDWH
Exhaust Vent Piping
Installation
Preparation
NOTE: A Fulton PDWH water heater
should not be connected to a common
venting system with other types of gas
appliances.
The water heater is equipped with an
exhaust vent connection located at the
rear of the water heater. (Figure 6) For
Models PDWH750 & PDWH1000 the
connections are 4" NPT threaded
female fittings.
The exhaust line must be sloped
down toward the unit with a pitch
of at least
1 / 4 " per foot. Failure to
do so can result in a condensate
pocket which can result in an
inoperative water heater. There must
be no low spots in the exhaust pipe, as
this can also result in a condensate
pocket. A high spot is acceptable,
provided the pitch from the high spot is
maintained back to the water heater to
the outside point of the exhaust. In
supporting piping, or routing it
through a rafter or wall, always use
vibration eliminating hangers around
the piping to prevent transmission of
pulsations. Always avoid rigid
connections between piping and
structural members of the building. Flue
exhaust pipes and fittings for all models
shall be stainless steel. The stainless
steel shall be UL temperature rated at
minimum air clearance to combustibles.
At 480° F temperature rating, a 5"
minimum air space clearance to
combustibles is required. Fulton pulse
combustion hydronic heating water
heaters require a special venting
system. Applicable Federal Codes are
NFPA 54/ANSI Z223.1 National Fuel
Gas Code and NFPA/ANSI 211
Chimneys, Fireplaces, Vents, and Solid
Fuel Burning Appliances. In Canada
refer to the venting section of CAN/CGA
B149.1 and .2. These codes contain
information on special gas vents. The
gas vent installer should be familiar with
these Federal Codes as well as local
codes and regulations.
The procedure for adhesive joining
stainless steel pipe and fittings follows:
Step 1
Do not mix stainless steel pipe with
galvanized or other alternatives for the
entire length of the system.
Step 2
All joints between sections of the vent
connector and the vertical conduit must
be sealed with a high temperature
sealant to prevent any possible leakage
of flue gas.
Step 3
Apply a bead of sealant, about
1 / 4 inch in
diameter, completely around the male
(without tabs) end of each conduit
section or elbow, between
1 /
4
and 3 /
8
inch from the end of the section. Also
run a similar sized bead down the seam
weld of each section, from the edge of
the pipe to the top of the bulge.
Step 4
Fully insert the male end of the section
into the female fitting of the section
below. Spread any sealant that squeezes
out around the circumference of the
joint. Attach the sections together
with the locking ring and tabs. Again
spread any extruded sealant around the
joint. Inspect the joint to ensure that flue
gases will not escape. If necessary,
apply additional sealant to any voids.
Allow the sealant 24 hours to cure
before operating the water heater.
Step 5
All pipes, elbows, and fittings used in
condensate piping from liquid drain to
floor drain shall be high temperature
plastic or stainless steel.
Exhaust Muffler
Installation
Follow steps 1-5 above to join the fittings.
For muffler drain installation:
1. For mufflers installed in the vertical
configuration the drain can be plugged.
2. For mufflers installed in the horizontal
configuration, the drain should be piped
to the drain line between the water heater
and the liquid drainer.
For best noise attenuation, the muffler
should be installed as close to the water
heater as possible.