Raypak 992B manual Low Water Cut-OffOptional, High and Low Gas Pressure Switches

sheets supplied with your heater paperwork. See the General Safety Section for safety precautions con- cerning domestic hot water applications.

gas pressure switch automatically shuts down the heater if gas manifold pressure rises above the recom- mended setting of 5.0 in. WC for natural gas, and 11.5 in. WC for propane gas.

Fig. 35: Operating Control

Low Water Cut-Off (Optional)

The low water cut-off automatically shuts down the burner whenever water level drops below the level of the sensing probe. A 5-second time delay prevents premature lockout due to temporary conditions such as power fluctuations or air pockets.

Fig. 36: Low Water Cut-Off

High and Low Gas Pressure Switches

The low gas pressure switch (standard) connection mounts upstream of the gas valve to ensure that suffi- cient gas pressure is present for proper regulator performance. The low gas pressure switch automati- cally shuts down the heater if gas supply drops below the factory setting of 5.0 in. WC for natural gas, and 10.0 in. WC for propane gas.

The high gas pressure switch (optional) connection mounts down-stream of the stage-1 gas valve. If the gas pressure regulator fails, the high gas pressure switch automatically shuts down the burner. The high

Fig. 37: High/Low Gas Pressure Switch

Fig. 38: Fan-Proving Switch

Fig. 39: Blocked Vent Switch

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