Raypak 399B-2339B 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.

switch automatically shuts down the burner. The high 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.

NOTE: Some jurisdictions may require two high gas pressure switches on models 1529B–2339B due to two ignition modules.

Fig. 31: 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. 32: Low Water Cut-Off

High and Low Gas Pressure Switches

The low gas pressure switch (standard on models 989B–2339B, optional on models 399B–899B) con- nection mounts upstream of the gas valve to ensure that sufficient gas pressure is present for proper regu- lator performance. The low gas pressure switch automatically shuts down the heater if gas supply drops below the factory setting of 5.0 in. WC for natu- ral 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

Fig. 33: High/Low Gas Pressure Switch

Fig. 34: Fan-Proving Switch

Fig. 35: Blocked Vent Switch

NOTE: The wiring diagrams in this manual show all standard options. Refer to the large wiring diagram provided with your heater for options installed on your specific unit(s).

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