Gas Supply Piping - Dunkirk Q90-125 Installation, Operation & Maintenance Manual

Check Gas Supply
Table 5 - Gas Supply Pressure
Pressure
Minimum
Maximum
Please check line pressure while unit is running.
• 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 6 and 7 for proper size.
• Verify your gas line complies with local codes and gas
company requirements.
Connecting Gas Piping
Table 6 - Natural Gas Piping Sizes
Pipe Capacity - BTU/Hr. Input
Pipe Length
½"
20' 92,000
40' 63,000
60' 50,000
Table 7 - Propane Gas Piping Sizes
Pipe Capacity - BTU/Hr. Input
Pipe
Copper Tubing
Length
⅝"
20' 131,000
40' 90,000
60' 72,000
(1)
Includes Fittings
Length of pipe or tubing should be measured from gas
meter or propane second stage regulator.
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 liquefi ed
petroleum gas on male threads only.
3. Use ground joint unions.
4. Install sediment trap upstream of gas controls.

7 - GAS SUPPLY PIPING

Natural Gas Propane Gas
4" w.c. 10" w.c.
10" w.c. 14" w.c.
(1)
¾" 1"
190,000 350,000
130,000 245,000
105,000 195,000
(1)
(2) Iron Pipe
¾" ½"
216,000 189,000
145,000 129,000
121,000 103,000
(2)
Outside Diameter
5. Use two pipe wrenches when making connection to
gas valve to keep it from turning.
Install manual main shutoff valve in vertical pipe
6.
about 5 feet (1.5m) above fl oor 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
Figure 14
1¼"
625,000
445,000
365,000
¾"
393,000
267,000
217,000
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 fl uid, or other leak detection method
acceptable to authority having jurisdiction. Do not
use matches, candles, open fl ames, or other methods
providing ignition source.
• Correct leaks immediately and retest.
15
- Gas Piping