Trane GEH 006 Manual page 38

Using Water Regulating Valves
The function of the water regulating
valve assembly is to minimize the
amount of water which flows through
the water-source heat pump. These
valves are most often used in systems
where the water is wasted, but may
also be used in boiler/cooling tower in-
volving variable speed pumping. In a
variable speed application, the valves
are used to meter desirable water flow
through the unit when the unit is run-
ning, and to stop water flow when the
unit is not running (but may not in-
clude a 100% shut-off).
The water regulating valve assembly
consists of two valves piped in paral-
lel. When the water-source heat
pump's compressor is de-energized,
both valves are closed, allowing no
water to flow through the unit. But,
when the unit compressor is ener-
gized, one of the valves is closed and
the other valve will allow water flow
through the unit.
In cooling mode, the valve control-
ling the water flow is referred to as a
direct acting valve. As the spring ten-
sion increases, the head pressure will
also increase. This is due to the de-
crease in water flow through the unit.
Note, the valve is being controlled by
the head pressure. As the head pres-
sure increases, the water flow increas-
es, and vice versa. The valve is
controlled by two pressures. The re-
frigerant pressure in the high side of
the system, and the spring pressure,
acting on the opposite side of the
valve.
Note: The spring tension on the direct
38
Application
Considerations
acting valve may be adjusted to main-
tain a desired head pressure.
When the unit is OFF, or is in the heat-
ing mode, the valve closes. This is be-
cause the pressure acting on the valve
is out of the spring set-range.
In the heating mode, the valve con-
trolling the water flow is referred to a a
reverse acting valve. As the spring ten-
sion increases, the suction pressure
will increase. This is due to the in-
crease in water flow through the unit.
Note, the valve is being controlled by
the suction pressure. As the suction
pressure decreases, the water flow in-
creases, and vice versa. The valve is
controlled by two pressures. The re-
frigerant pressure in the low side of
the system, and the spring pressure,
acting on the opposite side of the
valve.
Note: The spring tension on the re-
verse acting valve may be adjusted to
maintain a desired suction pressure.
When the unit is OFF, or is in the cool-
ing mode, the valve closes. This is be-
cause the pressure acting on the valve
is out of the spring set-range.
Both the direct acting and the reverse
acting valves should be tapped into
the same refrigerant line via a schraed-
er connection. This line must be a high
pressure line when the unit is in the
cooling mode, and a low pressure line
when the unit is in the heating mode.
The only line that will accommodate
this condition is the vapor line running
between the reversing valve and the
water-to-refrigerant heat exchanger.
Note: In many applications, a water
regulating valve may be used to meter
water flow to the equipment instead of
metering refrigerant flow to the equip-
ment. This is typically applied when
the equipment does not contain a ther-
mal expansion refrigerant metering
device. Trane places a thermal expan-
sion valve on all water-source and
ground-source heat pumps to provide
maximum performance of the equip-
ment. Capillary tube assemblies are
not used on Trane water-source or
ground-source heat pump equipment.
Therefore, a water regulating valve is
not required on most equipment appli-
cations.
WSHP-PRC001-EN