Combustion Air And Vent Pipe - Dunkirk 90-50 Installation, Operation & Maintenance Manual

Chilled Water piping
The boiler, when used in connection with a refrigeration system,
must be installed so the chiller medium is piped in parallel with the
boiler with appropriate valves to prevent the chilled medium from
entering the boiler.
Connections and Termination
Provisions for combustion and ventilation air must be in accordance
with section, Air For Combustion and Ventilation, of the National
Fuel Gas Code,ANSI 2223.1/NFPA54, or Sections 8.2, 8.3 or 8.4 of
National Gas and Propane Installation Code, CAN/CGA-B 149.1 , or
applicable provisions of the local building code.
These boilers require a dedicated direct vent system. All air for com-
bustion is taken directly from outdoors through the combustion air
intake pipe. All flue products are discharged to the outdoors through
the vent pipe.
Refer to Combustion Air And Vent Pipe section that follows,
1.
also see Figures 9 & 10 for combustion air and vent pipe
roof and sidewall termination. (Roof termination is preferred)
Combustion air and vent pipes must terminate together in same
atmo spheric pressure zone as shown. Construction through
which vent and air intake pipes may be installed is a maximum
24 inches, minimum ¼" thickness.
Combustion air and vent pipe fittings must conform to
2.
American National Standards Institute (ANSI) standards and
American Society for Testing and Materials (ASTM) standards
D1784 (schedule-40 CPVC), D1785 (schedule-40 PVC), D2665
(PVC-DWV), D2241 (SDR-21 and SDR-26 PVC), D2661 (ABS-
DWV), or F628 (schedule-40 ABS). Pipe cement and primer
must conform to ASTM standards D2564 (PVC) or D2235
(ABS).
In Canada construct all combustion air and vent pipes for this unit
of CSA or ULC certified schedule-40 CPVC, schedule-40 PVC,
PVC-DWV or ABS-DWV pipe and pipe cement. SDR pipe is NOT
approved in Canada.
Combustion air and vent piping connections on boiler are sized
3.
for 2" pipe. Any pipe size change (to 3") must be made outside
of the boiler casing in a vertical run of pipe to allow for proper
drainage of vent condensate. Due to potential for flue gas tem-
peratures over 155°F, the first five (5) feet of vent pipe must be
CPVC, the remaining vent pipe can be PVC. If any elbows are
employed within the first 5 feet of vent, they must be CPVC too.
Two (2) - 30" pieces of 2" CPVC pipe are furnished with the
boiler.
near boiler piping
The boiler piping system of a hot water boiler connected to heat-
ing coils is located in air handling units where they may be exposed
to refrigerated air circulation must be equipped with flow control
valves or other automatic means to prevent gravity circulation of the
boiler water during cooling cycle.

CombusTion air and VenT pipe

OF TyPICAL NON-METALLIC VENT MATERIAL
Material
PVC
CPVC
ABS
Radel -
A200
* Allowable temperatures based on Classifications covered in ASTM
D4396 [Deflection Temperatures under Load (264 psi) (1819KPa)].
** Allowable temperatures based on Classifications covered in ASTM D1784
[Deflection Temperatures under Load (264 psi) (1819KPa)].
*** Allowable temperatures based on Classifications covered in ASTM D3965
[Deflection Temperatures under Load (264 psi) (1819KPa)].
19
NOTICE
The transition from 2" pipe to 3" pipe must be
made in a vertical run.
MAxIMUM ALLOwABLE TEMPERATURES
HDT
°F °C °F
158 70
210 100
180 82
414 212
RTI
Standard
°C
ASTM F891 *
ASTM D2665 **
– –
ASTM D1785 **
ASTM D2241 **
ASTM D2846 **
– – ASTM F441 **
ASTM F442 **
ASTM D2661 ***
– –
ASTM F628 ***
UL-1738
– –
ULC S636