Dunkirk Q90-200 Series II - Manual (Page 21)

21
Check Gas Supply
• Gas pipe to boiler must be correct size for length of
run and total Btuh input of all gas utilization equipment
connected to it.
• See Tables 9 and 10 for proper size. Refer to NFPA54
for additional tables.
• Verify your gas line complies with local codes and gas
company requirements.
Table 8 - Gas Supply Pressure
Pressure Natural Gas Propane Gas
Minimum 4” w.c. 10” w.c.
Maximum 10” w.c. 14” w.c.
Please check line pressure while unit is running.
Table 9 - Natural Gas Piping Sizes
Pipe Length
Pipe Capacity - BTU/Hr. Input (1)
½” ¾” 1” 1¼”
20’ 92,000 190,000 350,000 625,000
40’ 63,000 130,000 245,000 445,000
60’ 50,000 105,000 195,000 365,000
Table 10 - Propane Gas Piping Sizes
Pipe
Length
Pipe Capacity - BTU/Hr. Input (1)
Copper Tubing (2) Iron Pipe
⅝”
¾” ½” ¾”
20’ 131,000 216,000 189,000 393,000
40’ 90,000 145,000 129,000 267,000
60’ 72,000 121,000 103,000 217,000
(1) Includes Fittings (2) Outside Diameter
Connecting Gas Piping
Refer to Figure 14 for general layout at boiler. Gas line
enters boiler through left side panel.
Boiler is equipped with ½” NPT connection on gas valve for
supply piping and ½” NPT ball valve for manual shut off.
Following rules apply:
1.
Use only those piping materials and joining methods
listed as acceptable by the authority having jurisdiction,
or in the absence of such requirements, National Fuel
Gas Code, ANSI Z223.1/NFPA 54.
2.
Use pipe joint compound suitable for liquefied
petroleum gas on male threads only.
3.
Use ground joint unions.
4.
Install sediment trap upstream of gas controls.
5.
Use two pipe wrenches when making connection to gas
valve to keep it from turning.
6.
Install manual main shutoff valve in vertical pipe about
5 feet (1.5m) above floor outside boiler jacket.
7.
Tighten all joints securely.
8.
Propane gas connections made by licensed propane
installer.
9.
Two stage regulation used by licensed propane
installer.
10.
Propane installer to verify Propane gas piping.
11.
Recommend use ½” union suitable for natural and
propane gas after ball valve to facilitate service on unit.
Leak Check Gas Piping
Pressure test boiler and gas connection before placing
boiler in operation.
• Pressure test over 1/2 psig (3.5 kPa). Disconnect boiler
and its individual gas shutoff valve from gas supply
system.
• Pressure test at 1/2 psig (3.5 kPa) or less. Isolate boiler
from gas supply system by closing manual gas shutoff
valve.
• Locate leakage using gas detector, noncorrosive
detection fluid, or other leak detection method
acceptable to authority having jurisdiction. Do not
use matches, candles, open flames, or other methods
providing ignition source.
• Correct leaks immediately and retest.
8 - GAS SUPPLY PIPING
Figure 15 - Gas Piping
Length of pipe or tubing should be measured from gas
meter or propane second stage regulator.