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must not be allowed to damage the fill media.
Use of a mixing valve can help prevent this.
If the cooling water remains in the lines
during heat mode, ensure that any method of
isolating the cooling water for heat mode
operation does not cause a closed loop within the
unit itself. Otherwise, heating of the closed fluid
loop can cause water expansion pressure in the
loop to quickly build well beyond the pressure
limitations of the fluid circuit and can cause
catastrophic failure of the fluid loop. Such an
event results in immediate end-of-life condition
for the unit. Such failure will not be considered a
warranty event.
As with the chilled/hot water connections,
balance valve should be installed on the cooling
water inlet and a stop valve installed on the
cooling water outlet. Both valves should be in
close proximity to the chiller-heater. After
thoroughly testing for leaks, insulate the piping
circuit, ensuring an adequate vapor barrier is
obtained. Be sure to allow access to any valves,
wells, and ports that may be present. Also,
ensure the chiller-heater panels are not restricted
by the insulation.
Additionally, there should be flush and drain
valves installed between the machine and the
balance/stop valves so as to allow for chemical
cleaning of the absorber-condenser coils should it
ever become necessary.
FREEZE PROTECTION
When the chiller-heater and/or associated
piping are installed in a location that is subject to
freezing conditions, appropriate anti-freeze steps
must be taken. Many anti-freeze methods are
available including heat tape, but the most
common method in the USA is the use of glycol
in the fluid loop.
Glycol may be permitted for use in Yazaki
chiller-heaters with certain restrictions and
observations.
1. In the chilled/hot water circuit, it should
only be used during heating operation. It
is not recommended for use in the chilled
water circuit in cooling mode as the loss of
heat transfer performance could result in tube
failure under certain extreme conditions.
2. Glycol may be used in the cooling water
circuit in any operating mode.
3. Do not use automotive glycol
(Antifreeze)
since it contains chemical additives that are
inappropriate and potentially damaging to the
Yazaki chiller-heater. Use only glycol
appropriate for use with copper tubing.
4. Do not exceed a mixture of 50% by weight.
5. Be aware that loss of performance will result
when glycol is used. In higher
concentrations, the impact can be very
significant.
6. Propylene Glycol is preferred wherever
possible. It has very similar anti-freeze
characteristics to Ethylene Glycol, but is non-
toxic. It is also less viscous than Ethylene
Glycol, which reduces the required pump
power. Finally, it provides a heat transfer
performance closer to that of water than EG.
7. Use of glycol can cause the unit to operate at
a slightly higher internal temperature since
heat transfer is dampened. This may result
in depletion of inhibitor at a faster rate than
what may be perceived as normal.
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