American Water Heater HPE10280H045DV manual Operational Overview, Heat Pump Water Heater Operation

Operational Overview

Heat Pump Water Heater Operation:

Heat pump water heaters remove heat from surrounding air and use that heat to heat water. By doing so, heat pump water heaters can operate much more efficiently and at significantly lower costs compared to standard electric water heaters.

This heat pump water heater has four (4) operating modes for maximum flexibility in meeting hot water needs under a variety of conditions. Available modes are: Efficiency, Hybrid, Electric and Vacation.

Operating Mode Descriptions:

Efficiency Mode provides the highest efficiency and lowest cost operation by using only the heat pump to heat water. Recovery time and efficiency will vary with ambient temperature and relative humidity. Efficiency will be greatest when both are high and recovery time will be shortest. At lower temperatures and relative humidity levels, efficiency will be lower and recovery will take longer. Heat pump operation is allowed from 45°F to 109°F ambient temperature. At ambient temperatures lower that 45°F and greater than 109°F the heat pump will not operate. Similarly, if the water temperature in the tank is less than 59°F, the heat pump will not operate. The unit will operate in electric mode until ambient and water temperatures return to the safe operating range of the heat pump.

Hybrid mode provides the best combination of energy efficiency and hot water delivery. The heat pump will be used to heat water after moderate hot water use. When a large quantity of hot water is used, the upper electric heating element will heat water in order to speed up recovery. Once the upper portion of the tank reaches set point, the element will shut off and the heat pump will heat water until the average tank temperature reaches set point. Hybrid mode provides the highest first hour hot water delivery with excellent economy.

Electric mode allows operation like a standard electric water heater, using the upper and lower heating elements to heat water. The heat pump is not used in this mode. The key advantage of using this mode is that it eliminates the cool air exhausted from the heat pump. During cold weather months, this may be desirable. Hot water delivery and operating costs are comparable to a standard electric water heater with similar tank capacity.

Vacation mode should be used when hot water will not be needed for a period of time greater than three

(3)days. In vacation mode electric elements are used to heat water and set point is a non-adjustable 60°F. Minimal electricity will be used and maintaining 60°F minimizes the risk of the water heater freezing in cold weather.

User Interface Module Overview:

The User Interface Module (UIM) is used to control the heat pump water heater. It displays useful information about the operating status of the water heater, the selected mode of operation and the set point temperature. Fault information will be displayed should a malfunction occur with one of the components or sub-systems. The UIM also is used to set the water heater to the desired set point temperature, mode of operation, temperature units (°F or °C) and to check the operating condition of the heat pump through the maintenance display, see “Accessing the Maintenance Display”(p. 21).

Initial Start Up:

When powered up for the first time (or when power is re-applied after a power outage or service work is performed), the control will run the dry fire check to establish that the tank is completely filled with water, see “Dry Fire Element Protection” (p.8). The UIM will display “Dry Fire” during this operation, which will take about four (4) minutes. After eight (8) minutes have elapsed, the fan should come on; after an aditional thirty (30) seconds, the heat pump compressor should turn on. Note that during the initial start up, the heat pump will come on regardless of operation mode selected. This is intended to allow for evaluation of the heat pump to ensure that it is operating properly. The heat pump will heat water until the set point temperature is reached in the tank; it will then shut off. After this initial start up is complete, the water heater will operate per operational mode setting, ambient air and tank water tamperatures, and set point temperature.

12