Dunkirk 90-50 Installation, Operation & Maintenance Manual page 25

Checking The gas piping
The boiler and its gas connection must be leak tested before placing
the boiler in operation. Open the manual shutoff valve. Test for leaks
by applying soap suds (or a liquid detergent) to each joint. Bubbles
forming indicate leak. CORRECT EVEN THE SMALLEST LEAK
AT ONCE.
Length of
Pipe - Ft.
20
40
60
Length of
Pipe - Ft.
20
40
60
* Outside diameter
figure 12 - gas piping
gas supply piping
TABLE #3 – GAS PIPE SIzES
NATURAL GAS
Pipe Capacity - BTU Per Hour Input Includes Fittings
1/2" 3/4"
92,000 190,000
63,000 130,000
50,000 105,000
PROPANE GAS
Pipe Capacity - BTU Per Hour Input Includes Fittings
Copper Tubing*
5/8" 3/4"
131,000 216,000
90,000 145,000
72,000 121,000
!
Never use a match or open flame to test for
leaks.
1"
350,000
245,000
195,000
1/2"
189,000
129,000
103,000
25
WARNING
1 1/4"
625,000
445,000
365,000
Iron Pipe
3/4"
393,000
267,000
217,000