Bard GSVS242-A, Руководство по установке

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Manual 2100-317J
Page 21 of 39
OPEN LOOP
(WELL SYSTEM APPLICATIONS)
NOTE:
Unit shipped from factory with 27 PSIG low
pressure switch wired into control circuit for
open loop applications.
WATER CONNECTIONS
It is very important that an adequate supply of clean,
noncorrosive water at the proper pressure be provided
before the installation is made. Insufficient water, in the
heating mode for example, will cause the low pressure
switch to trip, shutting down the heat pump. In
assessing the capacity of the water system, it is
advisable that the complete water system be evaluated
to prevent possible lack of water or water pressure at
various household fixtures whenever the heat pump
turns on. All plumbing to and from the unit is to be
installed in accordance with local plumbing codes. The
use of plastic pipe, where permissible, is recommended
to prevent electrolytic corrosion of the water pipe.
Because of the relatively cold temperatures encountered
with well water, it is strongly recommended that the
water lines connecting the unit be insulated to prevent
water droplets form condensing on the pipe surface.
Refer to piping, Figure 10. Slow closing
Solenoid
Valve (6)
with a 24 V coil provides on/off control of the
water flow to the unit. Refer to the wiring diagram for
correct hookup of the valve solenoid coil.
Constant Flow Valve (7)
provides correct flow of water
to the unit regardless of variations in water pressure.
Observe the water flow direction indicated by the arrow
on the side of the valve body. Following is a table
showing which valve is the be installed with which heat
pump.
Strainer (5) installed upstream of constant flow valve
(7) to collect foreign material which would clog the flow
valve orifice.
The figure shows the use of
shutoff valves (9)
and
(11)
,
on the in and out water lines to permit isolation of the
unit from the plumbing system should future service
work require this. Globe valves should not be used as
shutoff valves because of the excessive pressure drop
inherent in the valve design. Instead use gate or ball
valves as shutoffs, so as to minimize pressure drop.
Drain cock (8)
and
(10)
, and tees have been included to
permit acid cleaning the refrigerant-to-water coil should
such cleaning be required. See WATER CORROSION.
Drain cock (12) provides access to the system to check
water flow through the constant flow valve to insure
adequate water flow through the unit. A water meter is
used to check the water flow rate.
WELL PUMP SIZING
Strictly speaking, sizing the well pump is the
responsibility of the well drilling contractor. It is
important, however, that the HVAC contractor be
familiar with the factors that determine what size pump
will be required. Rule of thumb estimates will
invariably lead to under or oversized well pumps.
Undersizing the pump will result in inadequate water to
the whole plumbing system, but with especially bad
results to the heat pump – NO HEAT / NO COOL calls
will result. Oversized pumps will short cycle and could
cause premature pump motor or switch failures.
The well pump must be capable of supplying enough
water and at an adequate pressure to meet competing
demands of water fixtures. The well pump must be
sized in such a way that three requirements are met:
1. Adequate flow rate in GPM.
2. Adequate pressure at the fixture.
3. Able to meet the above from the depth of the
well-feet of lift.
TABLE 9
CONSTANT FLOW VALVES
(1) The pressure drop through the constant flow valve
will vary depending on the available pressure
ahead of the valve. Unless minimum of 15 psig
is available
immediately ahead of the valve, no
water will flow.
. o N t r a P
e l b a l i a v A . n i M
G I S P e r u s s e r P
e t a R w o l F
M P G
7 0 0 - 3 0 6 8 ) 1 ( 5 1 6
8 0 0 - 3 0 6 8 ) 1 ( 5 1 8
0 1 0 - 3 0 6 8 ) 1 ( 5 1 4
1 1 0 - 3 0 6 8 ) 1 ( 5 1 5
9 1 0 - 3 0 6 8 ) 1 ( 5 1 3