Heater Removal From A Common Vent System - Heat Transfer MODCON VWH 300 LP Installation & Maintenance

PART 6: VENTING, COMBUSTION AIR & CONDENSATE REMOVAL
vent pipe. If the exhaust pipe must be piped
around an obstacle that results in the creation
of a low point, condensate will collect in this
low point and form a blockage. This
condensate must be drained away using a
field-installed condensate drain assembly. All
vent pipes must be glued, properly
supported and the exhaust must be pitched
a minimum of ¼" per foot back to the boiler
to allow drainage of condensate. The
condensate drain piping should be a
minimum of ¾" PVC Rigid Piping, pitched at
a minimum of ¼" per foot away from the
boiler. (See Fig. 6-1, 6-2)
5. All piping must be fully supported. Use pipe
hangers at a minimum of 4 foot intervals to
prevent sagging of the pipe where
condensate may form. When placing support
brackets on vent piping, the first bracket must
be within 1 foot of the appliance and the
balance at 4 foot intervals on the vent pipe.
The boiler venting must be readily accessible
for visual inspection for the first three feet of
the boiler.
6. Do not use the boiler to support any piping.
7. A screened straight coupling is provided with
the boiler for use as an outside exhaust
termination.
8. A screened inlet air tee is provided with the
boiler to be used as an outside intake
termination.
H. HEATER REMOVAL FROM A COMMON
VENT SYSTEM
At the time of removal of an existing heater, the
following steps shall be followed with each
appliance remaining connected to the common
venting system placed in operation, while the
other appliances remaining connected to com-
mon venting system are not operating.
1. Seal any unused openings in the common
venting system.
2. Visually inspect the venting system for proper
size and horizontal pitch to determine if there
35
GAS-FIRED HOT WATER SUPPLY BOILER
is blockage, leakage, corrosion or other defi-
ciencies that could cause an unsafe condition.
3. If practical, close all building doors, windows
and all doors between the space in which the
appliance remains connected to the common
venting system located and other spaces in
the building. Turn on clothes dryers and any
appliances not connected to the common
venting system. Turn on any exhaust fans,
such as range hoods and bathroom exhausts,
at maximum speed. Do not operate a summer
exhaust fan. Close all fireplace dampers.
4. Place in operation the appliance being
inspected. Follow the lighting instructions.
Adjust the thermostat so the appliance will
operate continuously.
5. Test for spillage at the draft hood relief
opening after 5 minutes of main burner
operation. Use the flame of a match or candle
or smoke from a cigarette.
6. After it has been determined that each
appliance remaining connected to common
venting system properly vents when tested as
outlined, return doors, windows, exhaust fans,
fireplace dampers and any other gas burning
appliance to their previous condition of use.
7. Any improper operation of the common
venting system should be corrected so the
installation conforms with the National Fuel
Gas Code, ANSI Z223.1. When resizing any
portion of the common venting system, the
common venting system should be resized to
approach the minimum size as determined
using the appropriate tables in Appendix G in
the National Fuel Gas Code, ANSI Z 223.1
Note: For Canadian Installations, it is required
that Non Metallic Vent Installations conform to
ULC S636. Where plastic venting is not allowed,
HTP recommends AL294C Stainless Steel
Venting be used for Exhaust venting installa-
tions and "B" vent for intake air.
Please refer to 6-7 for U.L. Approved Stainless
Steel Vent Adapters.
Boiler Manual
(CONTINUED)