Options
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19
Revised 08/14
8 733 914 818 (2014/08)
SV Heat Pump Series
OPTIONS
Extended Range Option
SV heat pumps are supplied standard with
capillary style expansion device tuned to typical
boiler/tower system operating conditions. For
applications that will experience more extreme
fluid flow rates or temperatures (heating fluid
temperatures below 50°F and/or cooling fluid
temperatures below 60°F or above 100°F), an
extended range option is required.
The extended range option on the SV consists of a
bi-flow, balanced port thermal expansion valve and
an insulated water-to-refrigerant heat exchanger.
With the extended range option installed SV units
can provide heating with fluid temperatures as low
as 40°F and as high as 120°F and cooling with fluid
temperatures as low as 20°F and as high as 90°F.
Unit Mounted Non-Fused Disconnect
Switch
SV heat pumps can be supplied with an optional
unit mounted disconnect switch mounted to the
electrical corner post of the unit.
Field electrical wiring is connected to the switch
and the switch then routes power to the heat
pump electrical box. When the switch is in the
“OFF” position, the heat pump electrical box is
completely de-energized.
Hot Gas Reheat
(Available on size 015 and larger)
SV series heat pumps size 015 and larger can be
provided with hot gas reheat for active
dehumidification. In operation hot gas reheat
dehumidifies space by cooling the air and
removing moisture and then reheating the air back
to a neutral temperature using waste heat from the
compressor. The net effect is to decrease the
relative humidity of the space without changing
the sensible temperature.
The major components of the hot gas reheat
option are the hot gas reheat coil, the reheat
solenoid valve and the control circuit. When the
control circuit energizes the heat pump in reheat
mode, the heat pump will operate in the cooling
mode. The hot gas solenoid valve diverts the
compressor discharge gas to the reheat coil which
is mounted downstream of the unit evaporator.
This hot gas re-heats the cooled air coming off of
the evaporator.
To function, heat pumps with hot gas reheat must
be controlled by both a thermostat and a
humidistat (or a combination thermostat/
humidistat). The humidistat must provide a dry
contact closure on a rise in humidity above set
point.
At water temperatures of 85° F, the reheat coil can
recover 95% to 100% of the sensible capacity of
the evaporator. At water temperatures below 60°F,
the reheat coil can only recover 5% to 25% of the
sensible capacity of the evaporator.
Refer to the unit wiring diagram for control circuit
details.
DDC Controls
F
actory mounted DDC controls are available as an
option on SV series heat pumps. Please refer to the
DDC control manuals and literature for details on
this option.
Internal 2-Way Water Valve
In many applications, including variable pumping
and well water installations, a motorized water
valve is required on the heat pump water circuit.
On the SV series this water valve can be factory
mounted and wired internally to the unit.
The SV series internal water valve option features
a 24VAC motorized water valve rated to 450 psig
working pressure. This valve is wired to open on a
thermostat call for compressor operation (heating
or cooling) and will remain open as long as the
thermostat calls. The valve can remain seated with
up to 20 psi of back pressure on all sizes.
The valve consists of two main parts: the valve
body and the actuator. The valve body is brazed
into the leaving water line of the heat pump and is
a permanent part of the unit. The valve actuator
can be easily removed from the valve body for
service.
Refer to the water side pressure drop table in the
troubleshooting section of this manual to
determine the appropriate pressure drop across
the heat pump with and without the water valve
option.
Note that the ability of the reheat coil to reheat
cooled air back to a neutral temperature is
affected by the water temperature of the system.
Note that the 2-Way Water Valve option will add
additional pressure drop between the water in
and water out connections of the heat pump.
Note that this water valve cannot be used as an
isolation valve.
