15
Flow Controller 3
R e v. : F e b u r a r y 9 , 2 0 1 6
Antifreeze Charging
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WARNING!
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WARNING!
Always dilute alcohols with water (at least
50% solution) before using. Alcohol fumes are flammable
and can cause serious injury or death if not handled
properly.
It his highly recommended to utilize premixed antifreeze fluid
where possible to alleviate many installation problems and
extra labor.
The following procedure is based upon pure methanol and can
be implemented during the Full Flush procedure with three
way valves in the Figure 10D - Valve Position D. If a premixed
methanol of 15°F [-9.4°C] freeze protection is used, the system
can be filled and flushed with the premix directly to prevent
handling pure methanol during the installation.
1) Flush loop until all air has been purged from system and
pressurize to check for leaks before adding
any antifreeze.
2) Run discharge line to a drain and hook up antifreeze
drum to suction side of pump (if not adding below
water level through approved container). Drain flush cart
reservoir down to pump suction inlet so reservoir can
accept the volume of antifreeze to be added.
3) Calculate the amount of antifreeze required by first
calculating the total fluid volume of the loop from Table 3.
Then calculate the amount of antifreeze needed using Table
4 for the appropriate freeze protection level. Many southern
applications require freeze protection because of exposed
piping and Flow Controller to ambient conditions.
4) Isolate unit and prepare to flush only through loop.
Start flush cart, and gradually introduce the required
amount of liquid to the flush cart tank (always introduce
alcohols under water or use suction of pump to draw
in directly to prevent fuming) until attaining the proper
antifreeze protection. The rise in flush reservoir level
indicates amount of antifreeze added (some carts are
marked with measurements in gallons or liters). A ten
inch [25.4 cm] diameter cylinder, 3 foot [91.4 cm] tall
holds approximately 8 gallons [30.3 liters] of fluid plus the
hoses (approx. 2 gallons, [7.6 liters], which equals about
10 gallons [37.9 liters] total. If more than one tankful is
required, the tank should be drained immediately by
opening the waste valve of the flush cart noting the
color of the discharge fluid. Adding food coloring to the
antifreeze can help indicate where the antifreeze is in the
circuit and prevents the dumping of antifreeze out the
waste port. Repeat if necessary.
5) Be careful when handling methanol (or any alcohol).
The fumes are flammable, and care should be taken
with all flammable liquids. Open flush valves to flush
through both the unit and the loop and flush until fluid is
homogenous and mixed. It is recommended to run the
unit in the heating and cooling mode for 15-20 minutes
each to ‘temper’ the fluid temperature and prepare it for
pressurization. Devoting this time to clean up can be
useful. This procedure helps prevent the periodic “flat”
loop condition.
6) Close the flush cart return valve; and immediately
thereafter, close the flush cart supply valve, leaving a
positive pressure in the loop of approximately 50 psi [345
kPa]. This is a good time to pressure check the system
as well. Check the freeze protection of the fluid with the
proper hydrometer to ensure that the correct amount of
antifreeze has been added to the system. The hydrometer
can be dropped into the flush reservoir and the reading
compared to Chart 1A for Methanol, 1B for Propylene
Glycol, and 1C for Ethanol to indicate the level of freeze
protection. Do not antifreeze more than a +10°F [-12.2°C]
freeze point. Specific gravity hydrometers are available
in the residential price list. Repeat after reopening and
flushing for a minute to ensure good second sample
of fluid. Inadequate antifreeze protection can cause
nuisance low temperature lockouts during cold weather.
7) Close the flush cart return valve; immediately thereafter,
close the flush cart supply valve, shut off the flush cart
leaving a positive pressure in the loop of approximately
50-75 psi [345-517 kPa]. Refer to Figure 10E for more
details.
Heat Pump Low Water Temperature Cutout Selection
The CXM control allows the field selection of low water
(or water-antifreeze solution) temperature limit by clipping
jumper JW3 - FP1, which changes the sensing temperature
associated with thermistor FP1. Note that the FP1 thermistor
is located on the refrigerant line between the coaxial heat
exchanger and expansion device (TXV). Therefore, FP1 is
sensing refrigerant temperature, not water temperature,
which is a better indication of how water flow rate/
temperature is affecting the refrigeration circuit.
NOTICE:
Always verify proper freeze protection level
BEFORE changing FP1 setting.
The factory setting for FP1 is for systems using water (30°F
[-1.1°C] refrigerant temperature). In low water temperature
(extended range) applications with antifreeze (most ground
loops), jumper JW3 - FP1 should be clipped as shown in
Figure 11 to change the setting to 10°F [-12.2°C] refrigerant
temperature, a more suitable temperature when using
an antifreeze solution. All residential units include water/
refrigerant circuit insulation to prevent internal condensation,
which is required when operating with entering water
temperatures below 59°F [15°C].
NOTICE
: Failure to clip jumper JW3 - FP1 will result in a
service call in heating season when the unit locks out on low
water temperature fault.
