JOHNSON CONTROLS
10
FORM 150.68-EG1 (0212)
INSTALLATION OF VIBRATION ISOLATORS
An optional set of vibration isolators can be supplied loose
with each unit.
PIPEWORK CONNECTION
The following piping recommendations are intended to
ensure satisfactory operation of the unit. Failure to follow
these recommendations could cause damage to the unit,
or loss of performance, and may invalidate the warranty.
A fl ow switch must be installed in the customer pipework
at the outlet of the heat exchanger as shown in the
arrangement diagrams, and wired back to the control
panel using screened cable. This is to prevent damage
to the heat exchanger caused by inadequate liquid fl ow.
To prevent turbulent fl ow, there must be straight pipework
either side of the fl ow switch equal in length to at least 5
times the diameter of the pipe.
The fl ow switches used must have gold plated contacts
for low voltage/current operation
Alternatively, a differential pressure switch fi tted across
an orifi ce plate may be used, preferably of the high/low
limit type.
The liquid pumps installed in the pipework systems should
discharge directly into the unit heat exchanger sections of
the system. The pumps require an auto-starter (by others)
to be wired to the control panel.
Pipework and fi ttings must be separately supported to
prevent any loading on the heat exchanger(s). Flexible
connections are recommended which will also minimize
transmission of vibrations to the building. Flexible
connections must be used if the unit is mounted on anti-
vibration mounts as some movement of the unit can be
expected in normal operation.
Pipework and fittings immediately next to the heat
exchanger(s) should be readily demountable to enable
cleaning prior to operation, and to facilitate visual
inspection of the exchanger nozzles.
Each heat exchanger must be protected by a strainer,
preferably of 20 mesh, fi tted as close as possible to the
liquid inlet connection, and provided with a means of local
isolation.
The heat exchanger(s) must not be exposed to fl ushing
velocities or debris released during flushing. It is
recommended that a suitably sized by-pass and valve
arrangement be installed to allow fl ushing of the pipework
system. The by-pass can be used during maintenance to
isolate the heat exchanger(s) without disrupting fl ow to
other units.
Thermometer and pressure gauge connections should
be provided on the inlet and outlet connections of each
heat exchanger.
Drain and air vent connections should be provided at all
low and high points in the pipework to permit drainage of
the system, and to vent any air in the pipes.
Liquid systems at risk of freezing, due to low ambient
temperatures, should be protected using insulation and
heater tape and/or a suitable glycol solution. The liquid
pumps must also be used to ensure liquid is circulated
when the ambient temperature approaches freezing
point. Insulation should also be installed around the heat
exchanger nozzles.
Heater tape under the insulation is recommended,
supplied independantly and controlled by an ambient
temperature thermostat set to switch on at approximately
4ºF above the freezing temperature of the chilled liquid.
The heat exchanger is protected by a heater mat placed
under the insulation, which are powered from the unit
control system power supply. During cold weather when
there is a risk of freezing, chiller power should be left
switched on to provide the freeze protection function
unless the liquid systems have been drained.
Application Data - continued
