Control system for electric water heater with heat pump external heat source

Patent · Tue Sep 10 04:00:00 EDT 1985

OSTI ID:5829536

Shaffer, Jr, J E; Picarello, J F

A control system for an electric water heater operatively associated with an external heat source, such as a heat pump. The water heater includes a water storage tank provided with an electric tank heating unit having a tank thermostat which closes in response to water temperature in the tank, allowing a flow of current through the tank heating unit so as to turn it on to heat the water, and which opens when the tank thermostat has been satisfied, interrupting the current flow so as to turn the tank heating unit off. The control system as responsive to the initial current surge through the tank heating unit when the tank thermostat closes to interrupt the current flow to the tank heating unit so as to maintain the heating unit off and to turn on the external heat source and maintain it on until the tank thermostat opens. The initial current surge cleans the contacts of the tank thermostat by burning off any insulating oxide residues which may have formed on them. The control system includes means responsive to abnormal conditions which would prevent the external heat source from heating water effectively for turning off the external heat source and turning on the tank heating unit and maintaining the external heat source off and the tank heating unit on until the tank thermostat is satisfied.

• Assignee: Borg-Warner Corporation
• Patent Number(s): US 4540874
• OSTI ID: 5829536
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
320100* -- Energy Conservation
Consumption
& Utilization-- Buildings
APPLIANCES
CONTAINERS
CONTROL
CONTROL EQUIPMENT
CONTROL SYSTEMS
DESIGN
ELECTRIC HEATING
ELECTRICAL EQUIPMENT
ELECTRONIC CIRCUITS
EQUIPMENT
HEAT PUMPS
HEAT SOURCES
HEATERS
HEATING
OPERATION
RELAYS
STORAGE
TANKS
TEMPERATURE CONTROL
THERMOSTATS
TIMING CIRCUITS
WATER HEATERS