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Many geothermal units installed in homes have an optional feature called a hot water generator or desuperheater.
This component consists of a refrigerant-to-water heat exchanger installed at the discharge of the compressor. The
hot gas at this point is in a “superheated” condition. In the desuperheater, the refrigerant releases some of the heat
into the cooler water through the copper wall of the desuperheater heat exchanger. A small circulator moves the
water from the water heater to the heat pump and back to the water heater.
This excess hot gas is available in both the heating and cooling modes. However, there is a greater hot water
benefi t during cooling because some of the heat that is extracted from the air ends up in the superheat, and is trans-
ferred to the water. When operating in second stage heating, some units disable the circulator so that all the heat
energy is devoted to the air.
It is important to note that the Hot Water Assist function simply
assists
in
preheating
water. The temperature rise
through the unit is generally 5 -10º F.
The amount of hot water generated is a function of the model and run time of the unit. On very hot days and cold
days, the desuperheater could generate more hot water required for the home due to the long run times of the unit.
On milder days when the unit has short duty cycles, the electric elements in the water heater will maintain the de-
sired temperature so there will always be enough hot water for the homeowner.
Some installations use a single tank for storage of hot water. Other installations use two tanks to provide extra hot
water capacity with added effi ciency.
A safety device (sensor) shuts off the circulator for the desuperheater in the event that the water temperature
reaches 130
°
F
(54° C). The yellow status light will be illuminated. At this time your unit’s hot water pump will be de-
energized to prevent excessive temperatures. Don’t worry; hot water operation will automatically resume when the
tank cools off. This is not a fault condition, and the unit does not require resetting.
A switch located below the status lights, enables you to manually turn off the internal desuperheater pump. When
this switch is off, your unit’s hot water pump is manually disabled, and DHW OFF status light will be lit. This switch
may be used when the water heater is being serviced or replaced. This switch must be turned off when water fl ow
from the water heater to the unit is turned off or disconnected. Damage to the pump may otherwise occur.
Optional Hot Water Assist
PRODUCT INFORMATION FOR UNITS, OPTIONS & ACCESSORIES
