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ENVISION SERIES INSTALLATION MANUAL
Figure 11: Desuperheater Installation in Preheat TankFigure 10: Typical Desuperheater Installation
Drain Valve
In
P/T Relief
Valve
Cold
Water In
Hot
Water Out
DHW
Water In
DHW
Water Out
Venting Waste Valve
or Vent Coupling
3/4˝ x 3/4˝ x 1/2˝ tee
Drain Valve Drain Valve
In
P/T Relief
Valve
Venting Waste Valve
or Vent Coupling
DHW
DHW
3/4˝ x 3/4˝ x 1/2˝ tee
Water In
Hot
Water Out
Cold
Water In
Water Out
P/T Relief
Valve
Desuperheater Connections
To maximize the benets of the desuperheater a minimum 50-gallon water heater is recommended. For higher
demand applications, use an 80-gallon water heater or two 50-gallon water heaters connected in a series as shown
below. Electric water heaters are recommended. Make sure all local electrical and plumbing codes are followed when
installing a desuperheater.
Residential units with desuperheaters contain an internal circulator and ttings.
Note: Under certain conditions, Envision dual capacity units operate with very low refrigerant discharge temperatures,
producing little or no water heating capability. This scenario occurs when the unit is operating with cold entering source
water (loop or well). Allowing the desuperheater pump to operate during these conditions actually removes heat from the
DHW circulating through the unit. To overcome this, Envision unit microprocessors have been programmed to disengage
the desuperheater pump during such conditions. (During low capacity cooling operation, the pump will operate only if
the DHW temperature entering the unit is less than the liquid line temperature plus 35º F. During high capacity cooling
operation, the pump will operate only if the DHW temperature is less than the liquid line temperature plus 60º F.) Using
a preheat tank, as shown in Figure 11, will maximize desuperheater capabilities.
CAUTION: Elements will burn out if energized dry.
Water Tank Preparation
To install a unit with desuperheater, follow these installation guidelines.
Turn off the power to the water heater.
Attach a water hose to the water tank drain connection and run the other end of the hose to an open drain or
outdoors.
Close the cold water inlet valve to the water heater tank.
Drain the tank by opening the valve on the bottom of the tank, then open the pressure relief valve or hot water
faucet.
Flush the tank by opening the cold water inlet valve to the water heater to free the tank of sediments. Close when
draining water is clear.
Disconnect the garden hose and remove the drain valve from the water heater.
Refer to Plumbing Installation and Desuperheater Startup on page 14.
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