TempMaster Omni Premier 25 Ton, Руководство по установке и обслуживанию

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Table 51: Staged and modulating gas heat
Staged and modulating gas heat
Staged
gas heat
Modulating
gas heat
Model
Gas input
capacity (MBH)
Maximum output
capacity (MBH)
Minimum
airflow (CFM)
Gas connection
size (in.)
Steps Turndown
250 202.5 5,000 0.75 2 10:1
500 405 5,000 1.00 2 20:1
25 ton
to 30 ton
750 607.5 5,000 1.00 4 30:1
500 405 8,000 1.00 2 20:1
750 607.5 8,000 1.00 4 30:1
40 ton
to 50 ton
1250 1012.5 8,000 1.25 6 50:1
500 405 12,000 1.00 2 10:1
1000 810 12,000 1.25 4 20:1 60 ton
1500 1215 12,000 1.50 6 30:1
500 405 14,000 1.00 2 10:1
1000 810 14,000 1.25 4 20:1
70 ton
to 80 ton
1500 1215 14,000 1.50 6 30:1
Note:
• For proper operation, the building supplied natural gas pressure should be 7 iwg to 14 iwg (liquid
propane pressure should be 12 iwg to 14 iwg).
• Temperature rise can be calculated where temperature rise = (gas input capacity (Btu) x 0.81) /
(CFM x 1.085).
• Maximum leaving air temperature cannot exceed 120.0°F (48.8°C).
Figure 34: Typical gas piping connection
Table 52: Sizing of inlet gas piping
Nominal iron pipe size
Length (ft)
1-1/4 in. 1-1/2 in. 2 in.
10 1,404 2,103 3,050
20 965 1,445 2,100
30 775 1,116 1,650
40 663 993 1,450
50 - 880 1,270
60 - 798 1,150
70 - 734 1,050
80 - 638 990
Note: Maximum capacity of pipe in cubic feet
of gas per hour (based upon a pressure drop of
0.5 iwg and 0.6 specific gravity gas).
Gas connection
• The gas supply line can enter the unit through
a bottom or side entry access hole.
• Run the gas supply line either inside the
building and penetrate the roof near the gas
inlet access, or install the line exposed on the
roof of the building.
• If gas supply line pressure is greater than 0.5
psig or 13.5 iwg, a properly sized regulator
must be installed.
• Refer to Figure 34 for typical gas piping
arrangement.
• Follow all local codes when installing the gas
supply line.
Gas piping recommendation
• A drip leg and a ground joint union must be
installed in the gas piping.
• When required by local codes, a manual shut-
off valve must be installed outside of the unit.
Tempmaster ® Omni™ Premier 25 Ton to 80 Ton Rooftop Units Installation and Maintenance Guide
77
Tempmaster