13
NSZ/NDZ INSTALLATION MANUAL
Figure 11: Hot Water Generator Installation
in Preheat Tank
Figure 10: Typical Hot Water Generator 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
To maximize the benefits of the hot water generator 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 hot water generator. Residential
units with hot water generators contain an internal
circulator and fittings. A water softener is recommended
for hard water applications (greater than 10 grains or 170
ppm total hardness).
NOTE:
Under certain conditions, Envision dual capacity
units operate with very low refrigerant discharge
temperatures, producing little or no water heating
CAUTION: Elements will burn out if energized dry.
Water Tank Preparation
To install a unit with hot water generator, follow these
installation guidelines.
Turn off the power to the water heater.
1.
Attach a water hose to the water tank drain connection
2.
and run the other end of the hose to an open drain or
outdoors.
Close the cold water inlet valve to the water heater
3.
tank.
Drain the tank by opening the valve on the bottom
4.
of the tank, then open the pressure relief valve or hot
water faucet.
Hot Water Generator Connections
capability. This scenario occurs when the unit is operating
with cold entering source water (loop or well). Allowing
the hot water generator 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
hot water generator 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 35° F. During high capacity
cooling operation, the pump will operate only if the DHW
temperature is less than the liquid line temperature plus
60°F.) Using a preheat tank, as shown in Figure 11, will
maximize hot water generator capabilities.
Flush the tank by opening the cold water inlet valve to
5.
the water heater to free the tank of sediments. Close
when draining water is clear.
Disconnect the garden hose and remove the drain
6.
valve from the water heater.
Refer to Plumbing Installation and Hot Water Generator
7.
Startup.
