Bryant TSTATBBN2S01-C Manual de instalación descargar pdf (Pagina 9)

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Water Quality

Water quality should be plentiful and of good quality.

Table 4 shows recommended water quality guidelines.

The unit can be ordered with either a copper or cupro-

nickel water heat exchanger. Copper is recommended for

closed loop systems and open loop ground water systems

that are not high in mineral content or corrosiveness.

In conditions anticipating heavy scale formation or

in brackish water, a cupro-nickel heat exchanger is

recommended. In ground water situations where scaling

could be heavy or where biological growth such as

iron bacteria will be present, a closed loop system is

recommended. Heat exchanger coils may over time

lose heat exchange capabilities due to a build up of

mineral deposits inside. These can be cleaned only by a

qualiﬁ ed service mechanic as acid and special pumping

equipment are required. Note: Desuperheater coils can

likewise become scaled and possibly plugged. In areas

with extremely hard water, the home owner should

be informed that the heat exchanger may require

occasional acid ﬂ ushing.

Expansion Tank

Use a closed, bladder-type expansion tank to minimize

mineral formation due to air exposure. The expansion

tank should be sized to handle at least one minute run

time of the pump to prevent premature pump failure using

its drawdown capacity rating. The pump should be sized

to the homeʼs domestic water load (5-9 gpm) plus the

heat pump water load. Discharge water from the unit is

not contaminated in any manner and can be disposed of

in various ways, depending on local building codes, i.e.

recharge well, storm sewer, drain ﬁ eld, adjacent stream

or pond, etc. Most local codes forbid the use of sanitary

sewer for disposal. Consult your local building and zoning

department to assure compliance in your area.

OPEN LOOP - WELL WATER SYSTEMS

Water Control Valve

Note the placement of the water control valve. Always

maintain water pressure in the heat exchanger by placing

water control valves at the outlet of the unit to prevent

mineral precipitation. Pilot operated or slow closing

valveʼs solenoid valves are recommended to reduce water

hammer. If water hammer persists, a mini-expansion tank

can be mounted on the piping to help absorb the excess

hammer shock. Insure that the total "VA" draw of the

valve can be supplied by the unit transformer.

For instance

the slow closing valve can draw up to 35VA. This can

overload smaller 40 or 50 VA transformers depending

on the other controls employed. A typical pilot operated

solenoid valve draws approximately 15VA. Note the

wiring diagram in Figure 20.

Flow Regulation

Flow regulation can be accomplished by two methods.

Most water control valves have a ﬂ ow adjustment built

in. By measuring the pressure drop through the unit heat

exchanger ﬂ ow rate can be determined and compared

to Table 9. Since the pressure is constantly varying two

pressure gauges might be needed. Simply adjust the

water control valve until the desired ﬂ ow of 1.5 to 2 gpm

per ton is achieved. Secondly a ﬂ ow control device may

be installed. The devices are typically an oriﬁ ce that is

designed to allow a speciﬁ ed ﬂ ow rate. These are mounted

on the outlet of the water control valve. On occasion these

valves can produce a velocity noise that can be reduced

by applying some back pressure. This is accomplished

by slightly closing the leaving isolation valve of the well

water setup.

Freeze Protection Setting

CXM or DXM Control:

When well water is used, the FP1 jumper (JW3) should be

NOT be clipped, but should be left in the factory position

of water setting (30°F). See Freeze Protection Selection.

Figure 11. Typical Well Water/Open Loop System

1 2 3 4 5 6 7 8 9 10 11 12 13 14 ... 31 32

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