Raypak 503-2003 manual High Limit-AutoReset Optional, Modulating Temperature Control, Flow Switch

Fig. 38: High Limit (Manual Reset)

High Limit—Auto Reset (Optional)

This heater may be equipped with an optional adjust- able auto reset high limit temperature device.

The optional adjustable auto reset high limit is located inside the heater junction box. Adjust the setting to approx. 20°F (10°C) above desired outlet temperature.

Fig. 39: Adjustable High Limit (Auto Reset)

Modulating Temperature Control

This heater is equipped with a Raypak modulating temperature control. Refer to information starting on page 30 for information on the setting and use of this control.

Fig. 41: Modulating Temperature Control

Low Water Cut-Off (Optional)

The optional 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 pre- vents premature lockout due to temporary conditions such as power fluctuations or air pockets.

Flow Switch

This standard, dual-purpose control, mounted and wired in series with the main gas valve, shuts off heater in case of pump failure or low water flow.

Fig. 42: Low Water Cut-Off

High & Low Gas Pressure Switches (Optional)

The optional low gas pressure switch connection mounts upstream of the gas valve (on the inlet flange to the gas valve) and is accessible through the remov- able access panels on the rear of the heater to reset the gas pressure switch, as necessary. It is used to ensure that sufficient gas pressure is present for prop- er valve/regulator performance. The low gas pressure switch automatically shuts down the heater if gas sup-

Fig. 40: Flow Switchply drops below the factory setting of 3.0 in. WC for 37 natural gas or propane gas.