Technical data

Before filling the system, ensure that it is
free from foreign matter, sand, stones,
rust flakes, solder, slag or other materials
which could damage the evaporators.
It is advisable to by-pass the unit when flushing out
the lines.
Water used to fill the circuit may have to
be treated to ensure that the pH value is
correct.
Standard evaporators provided on YCWM/YCRM
units are designed to chill mixtures of water and
ethylene glycol with a corrosion-inhibiting additive
down to -10 °C (R22) and -5 °C (R407C).
The amount of ethylene glycol to be added is as
follows.
Amounts are shown as a percentage by weight of
the circuit design water content:
operation from + 5 to 0 °C : 20%
operation from 0 to -5 °C : 30%
operation from -5 to -10 °C : 40%
4.3 Condenser External Water System
The external water hydraulic circuit must
ensure constant water flow to the
condensers under all operating or
adjustment conditions.
For cooling of YCWM units, condensers are
usually piped in conjunction with a cooling tower,
although in some cases they can be cooled by well
water.
With water cooled units it is necessary to control
coolant flow and/or temperature into the condenser
to maintain refrigerant pressure constant to ensure
satisfactory operation.
For a cooling tower system the simplest forms of
control are to use fan cycling, fan speed control, or
air damper control, with the tower having a
thermostat in its sump.
If these methods are not available, or a cooling
tower is not the source of cooling water, then a
three way valve recirculation system can be used.
The external water system should consist of the
following:
n
A circulation pump providing sufficient flow
and hydraulic head.
n
The primary system water content should be
no less than 5 litres per kW of cooling capacity.
The water used for the condenser external water
system should have a hardness value within 10 to
15 °Fr.
In addition:
n
Install a filter/strainer on the inlet side of the
condenser(s).
n Install shutoff valves on the condenser(s) inlet
and outlet water lines.
n Install a valved by-pass around the
condenser(s).
n
Install air vent valves at the highest points of
the lines.
n
Provide suitable drainage points (with plugs,
cocks, etc.) at the lowest points of the lines.
Key
I Pressure R Drain tap
T Temperature F Strainer
S Gate valves F1 Flow switch
S1 By-pass valve
4-2 035B40022-000
S
SS
Condenser
External Water System
T
T
I
I
S1
R
R
F1
F
S