Suburban ST-42 On-Demand Water Heater

The Suburban ST-42 On-Demand Water Heater provides an endless supply of controlled outlet water temperature when hot water is requested by the user. This occurs when the user opens a hot water faucet or other plumbing fixture. The water heater senses the flow of water and initiates startup. The combustion air fan turns on and proper flow of airis detected by the control unit. The combustion chamber purges, and the burner will ignite. Successful burner ignition is proven by the flame sense electrode. The time required for proper burner ignition is approximately 7 seconds after the user turns on a faucet or other plumbing fixture. Several attempts for ignition may be required to purge air from the gas line.

After ignition the water heater will begin to control outlet water temperature but may take several seconds to reach the user due to cold water in the hot water line. Burners will modulate to accurately control the outlet water temperature. Under low flow conditions, a high BTU stage will disengage and operate at a very low BTU, saving the user unnecessary propane usage and further improving temperature control characteristics.

Flame Out Protection – Should the flame be extinguished inadvertently due to low propane gas pressure or burner malfunction, the gas supply immediately turns off.

Low Voltage / High Voltage Protection – If the voltage supplied to the water heater drops below 10VDC or rises above 17VDC, the appliance will not operate.

Overcurrent Protection – If there is a short circuit in the appliance (>10A), an internal fuse is activated and the appliance turns off. If this occurs the fuse will needreplaced.

Flue Fan Monitoring – If there is a malfunction in the airflow of the combustion air fan, the gas supplied to the burner immediately turns off.

Hot Water Temperature Protection – A water high-temperature switch prevents excessively hot water in case of a malfunction.

Active Freeze Protection –Protects the unit from freezing temperatures so long as power and gas are provided to the unit.

High Pressure Protection – A built-in pressure relief valve protects the unit from surges of high water pressure.

Specifications
Model: ST-42
Max Heat Input: 42,000 BTU
Min Heat Input: 8,000 BTU
Orifice Size: 0.037"
Max Inlet Gas Pressure: 14 in-wc
Min Inlet Gas Pressure: 10.5 in-wc
Rated Gas Inlet Pressure: 11 in-wc
Total Amp Draw: <10
Max Water Pressure: 125 PSI
Min Flow Rate: 0.7 GPM
Gas Connection: 3/8" male flare
Hot and Cold Water Connection: 1/2" male NPT
Nominal Input Voltage: 12V DC
Dimensions: 12-1/2"H x 12-3/4"W x 13"D
Weight (Unit Only): 19 lbs.
Weight (With Door): 23.5 lbs.