Trane R Series Installation Operation & Maintenance page 38

38
Installation - Mechanical
Notes for Chart 3:
1. Solution freeze point is 2.2°C
below operating point saturation
temperature.
2. LRTC is 2.2°C below freeze point.
Procedure:
1. Is operating condition contained
within Chart? If not, see
"Specials" below.
2. For leaving-fluid temperatures
greater than 4.4°C, use settings
for 4.4°C.
3. Select operating conditions from
chart. For example: Standard
Unit, 3.3°C Delta T, 0°C leaving
water temperature.
4. Read off recommended % glycol,
for example 16%.
5. Go to Chart 3. From % glycol,
select low refrigerant temperature
cutout setting, for example -8.6°C.
CAUTION
1. Additional glycol beyond the
recommendations will adversely
effect unit performance. The unit
efficiency will be reduced and the
saturated evaporator temperature
will be reduced. For some
operating conditions this effect
can be significant.
2. If additional glycol is used, then
use the actual % glycol to
establish the low refrigerant
cutout set point.
3.The minimum low refrigerant
cutout set point allowed is -
20.6°C. This minimum is
established by the solubility
limits of the oil in the refrigerant.
CAUTION! The recommended flows
to achieve a negative temperature
are the low limit. In order to
guarantee the leaving water
temperature, do not allow for
temperatures below this limit.
Specials:
1. The following constitute a special
that must be calculated by
engineering:
• Freeze inhibitor other than
Ethylene Glycol or Propylene
Glycol.
• Fluid Delta T outside of the
range of 2°C to 6°C. Unit
configurations other than
Standard, Standard with extra
pass, and High Efficiency.
• % glycol greater than maximum
for a column in Charts 1 and 2.
For example: On the Standard
unit 6°C Delta T, Ethylene
Glycol, the maximum % glycol
is 34%.
2. Specials should be calculated by
engineering. The purpose of the
calculation is to make sure that
the design saturated temperature
is greater than -16.1°C.
Additionally, the calculation must
verify that the fluid freeze point is
a minimum of 2.2°C lower than
the design saturation
temperature. The low evaporator
temperature cutout will be -2.2°C
below the freeze point or -20.6°C,
whichever is greater.
RLC-SVX02G-E4