Patterson-Kelley MOD-04 ユーザーズマニュアル

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 Modu-Fire
® 
Gas-Fired Boiler 
Installation 
 
 
 11 
3.7.1  Gas Supply Piping by Installer 
The boiler and all gas piping connections should be 
pressure-tested and must be checked for leaks be-
fore being placed into service.  Test with com-
pressed air or inert gas if possible. 
The boiler must be disconnected at the boiler man-
ual shut-off valve (located at the end of the supplied 
gas train) from the gas supply piping system during 
any pressure testing of the system at pressures in 
excess of 1/2 psig (14 inch w.c.). 
During any pressure testing of the gas supply piping 
system at pressures equal to or less than 1/2 psig (14 
inch w.c.), the boiler should be isolated from the gas 
supply piping system by closing the manual shut-
off. 
Some leak test solutions, including soap and water, 
may cause corrosion.  These solutions should be 
rinsed-off with water after testing. 
 
3.7.2  Gas Bleeds and Vents by Installer 
If your unit is equipped with a diaphragm gas valve, 
the bleed vents on the diaphragm gas valves have 
been factory-piped to terminate at the burner, as re-
quired by ANSI Z21.13.  This feature provides com-
bustion of any gas which leaks past a ruptured dia-
phragm during operation.  Gas vents to outdoor air 
must be provided for the main pressure regulator.  
The pilot regulator is equipped with a vent limiting 
device and does not require external venting! 
•  When installing per ASME CSD-1, discon-
nect factory piped bleed vents and vent the 
diaphragm gas valves to outdoor air (field 
piping.) 
If a N.O. (normally open) vent valve is provided, it 
must be vented independently of any other bleeds 
and vents.  Discharge of vent lines should be pro-
tected by an insect screen. 
The air gas ratio control valve is equipped with a 
“reference chamber vent filter” which does not re-
quire any additional venting.  This connection is 
labeled COMBUSTION / ATMOSPHERE.  
If local conditions require venting to outdoors, the 
vent line connection must be piped by the installer 
in accordance with the National Fuel Gas Code 
(NFPA 54), ANSI Z223.1, which states: 
“In the case of vents leading outdoors, means shall 
be employed to prevent water from entering this 
piping and also to prevent blockage of vents by in-
sects and foreign matter.” 
 
The National Fuel Gas Code Handbook goes on to 
say that “Insects, insect nests, ice, or freezing rain 
can block outdoor vents....” 
 
The pilot regulator is equipped with a vent limiting 
device and does not require external venting!   
Gas Vents by Installer 
Note:  Provide a drip leg in all vent/bleed lines.  
All vent lines should be pitched up at all times to 
prevent building a trap into the vent line. 
“Vent limiters” are NOT to be installed on this 
boiler. 
The air gas ratio control valve is equipped with a 
“reference chamber vent filter” which does not re-
quire any additional venting.   
 
3.8
  
B
OILER 
W
ATER 
P
IPING
 
 
3.8.1  Piping Design 
 
Water Flow in System 
Ideal operation of the P-K MODU-FIRE
®
 Boiler 
would consist of a 20º F temperature differential 
across the heat exchanger at High fire.  Insufficient 
flow may result in excessive short cycling of the 
boiler and eventual damage or premature failure of 
the equipment. 
Minimum Return Water Temperature should be 
greater than 130º F to avoid problems of condensa-
tion on the outside of the heat exchanger or in the 
flue passages. 
Proper flow rates and return water temperature may 
be achieved through a combination of primary and 
secondary flow loops. Multiple zones and pumps 
may result in different flow rates at different times.