High Altitude
The manifold pressure, gas orifice and pressure switch may require adjustment or replacement to ensure proper operation at higher altitudes. Tables 24 through 27 shows
manifold pressure, pressures switch and gas conversion kits at all altitudes.
IMPORTANT
For safety, shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug.
TABLE 24
Manifold Pressure Settings
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| Manifold | Manifold | Manifold | Supply Line | |||||
Unit |
| Orifice Size | Orifice Size | Pressure in.wg. | Pressure in.wg. | Pressure in.wg. | Pressure | |||||
Gas | 7501 − | 0−4500 ft. | 4501−7500 ft. | 7501 − 10,000 ft.2 | in. w.g. | |||||||
Input | 0 − 7500 ft. | 10,000 ft.1 |
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| Low | High | Low | High | Low | High | Min | Max | ||||
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| Fire | Fire | Fire | Fire | Fire | Fire | |||
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| Natural | .063 | .055 | 1.7 | 3.5 | 1.6 | 3.4 | 1.7 | 3.5 | 4.5 | 13.0 | |
070 |
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LP/propane3 | .039 | .037 | 4.9 | 10.0 | 4.9 | 10.0 | 4.9 | 10.0 | 11.0 | 13.0 | ||
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| Natural | .063 | .055 | 1.7 | 3.5 | 1.5 | 3.0 | 1.7 | 3.5 | 4.5 | 13.0 | |
090 |
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LP/propane3 | .039 | .037 | 4.9 | 10.0 | 4.9 | 10.0 | 4.9 | 10.0 | 11.0 | 13.0 | ||
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| Natural | .063 | .055 | 1.7 | 3.5 | 1.5 | 3.2 | 1.7 | 3.5 | 4.5 | 13.0 | |
110 |
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LP/propane3 | .039 | .037 | 4.9 | 10.0 | 4.9 | 10.0 | 4.9 | 10.0 | 11.0 | 13.0 | ||
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1This is the only permissible derate for these units.
2Natural gas high altitude orifice kit required.
3A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion procedure.
NOTE − Units may be installed at altitudes up to 4500 ft. above sea level without modifications.
TABLE 25
High Altitude Pressure Switch Kits
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| High Altitude |
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Unit |
| Pressure Switch Kit | ||
Input |
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0 − 4500 ft. | 4501 − 7500 ft. | 7501 − 10,000 ft. | ||
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070 | No Change | No Change | 73W36 | |
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090 | No Change | 69W56 | 73W36 | |
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110 | No Change | 69W56 | 73W35 | |
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TABLE 26
Honeywell Gas Valve Conversion Kits
| High Altitude |
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| LP/Propane | |
| Natural Gas to | to | |||
| Natural Gas | ||||
| LP/ Propane Kit | Natural Gas | |||
Unit | Orifice Kit | ||||
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| Kit | |||
Input |
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| 7501 − | 0 − 7500 ft. | 7501 − | 0 − 7500 ft. | |
| 10,000 ft. | 10,000 ft. | |||
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070 | 73W37 | 51W02 | 73W38 | 69W79 | |
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090 | 73W37 | 51W02 | 73W38 | 69W79 | |
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110 | 73W37 | 51W02 | 73W38 | 69W79 | |
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TABLE 27
White Rodgers Gas Valve Conversion Kits
| High Altitude |
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| LP/Propane | |
| Natural Gas to | to | |||
| Natural Gas | ||||
| LP/ Propane Kit | Natural Gas | |||
Unit | Orifice Kit | ||||
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| Kit | |||
Input |
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| 7501 − | 0 − 7500 ft. | 7501 − | 0 − 7500 ft. | |
| 10,000 ft. | 10,000 ft. | |||
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070 | 77W05 | 77W07 | 77W11 | 77W09 | |
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090 | 77W05 | 77W07 | 77W11 | 77W09 | |
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110 | 77W05 | 77W07 | 77W11 | 77W09 | |
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Page 41
