CHECKING GAS PIPING
CAUTION
To prevent personal injury or property damage due to fire, the following instructions must be performed regarding gas connections, pressure testing, location of shutoff valve and installation of gas piping.
Before placing in operation, leak test the unit and gas connections. To avoid the possibility of explosion or fire, never use a match or open flame to test for leaks. Never exceed specified pressures for testing. Higher pressure may damage the gas valve and cause overfiring, resulting in heat exchanger failure.
This unit and shutoff valve must be disconnected from the gas supply piping system before supply piping system pressure testing with test pressures in excess of 1/2 psig (3.48 kPa).
This unit must be isolated from the gas supply system by closing its manual shutoff valve before pressure testing of gas supply piping system with test pressures equal to or less than 1/2 psig (3.48 kPa).
For satisfactory operation, propane gas pressure must be 10 inch WC at the furnace manifold with all gas appliances in operation. Maintaining proper gas pressure depends on three main factors:
1.Vaporization rate, depending on temperature of the liquid, and “wetted surface” area of the container or containers.
2.Proper pressure regulation.
3.Pressure drop in lines between regulators, and be- tween second stage regulator and the appliance. Pipe size will depend on length of pipe run and total load of all appliances.
Complete information regarding tank sizing for vaporiza- tion, recommended regulator settings, and pipe sizing is available from most regulator manufacturers and propane gas suppliers.
Since propane gas will quickly dissolve white lead or most standard commercial compounds, special pipe dope must be used. Shellac base compounds resistant to the actions of liquefied petroleum gases such as Gasolac, Stalactic, Clyde’s or John Crane are satisfactory.
Refer to Figure 19 for typical propane gas installations.
TANKS AND PIPING - PROPANE GAS UNITS
WARNING
To prevent death, personal injury or property damage due to fire or explosion caused by a propane gas leak, install a gas detecting warning device. Since rust can reduce the level of odorant in propane gas, a gas detecting warning device is the only reliable way to detect a propane gas leak. Contact a local propane gas supplier about installing a gas detecting warning device.
WARNING
All metal inserts, screens or turbulators must be removed from the heat exchanger tubes when using propane gas. Failure to comply could cause serious personal injury or death. Failure to comply with this requirement will also void warranty coverage.
All propane gas equipment must conform to the safety standards of the National Board of Fire Underwriters (See NBFU Manual 58).
Figure 19
Propane Gas Installation (Typ.)
PROPANE GAS PIPING CHARTS
Sizing Between First and Second Stage Regulator
Maximum Propane Capacities listed are based on 2 psig pressure drop at 10 psig setting. Capacities in 1,000 BTU/hour.
Pipe or |
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| Nominal Pipe Size | |
Tubing |
| Tubing Size, O.D. Type L |
| Schedule 40 | |||
Length, | 3/8" | 1/2" | 5/8" | 3/4" | 7/8" | 1/2" | 3/4" |
Feet |
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10 | 730 | 1,700 | 3,200 | 5,300 | 8,300 | 3,200 | 7,500 |
20 | 500 | 1,100 | 2,200 | 3,700 | 5,800 | 2,200 | 4,200 |
30 | 400 | 920 | 2,000 | 2,900 | 4,700 | 1,800 | 4,000 |
40 | 370 | 850 | 1,700 | 2,700 | 4,100 | 1,600 | 3,700 |
50 | 330 | 770 | 1,500 | 2,400 | 3,700 | 1,500 | 3,400 |
60 | 300 | 700 | 1,300 | 2,200 | 3,300 | 1,300 | 3,100 |
80 | 260 | 610 | 1,200 | 1,900 | 2,900 | 1,200 | 2,600 |
100 | 220 | 540 | 1,000 | 1,700 | 2,600 | 1,000 | 2,300 |
125 | 200 | 490 | 900 | 1,400 | 2,300 | 900 | 2,100 |
150 | 190 | 430 | 830 | 1,300 | 2,100 | 830 | 1,900 |
175 | 170 | 400 | 780 | 1,200 | 1,900 | 770 | 1,700 |
200 | 160 | 380 | 730 | 1,100 | 1,800 | 720 | 1,500 |
To convert to capacities at 15 psig settings - multiply by 1.130
To convert to capacities at 5 psig settings - multiply by 0.879
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