Specifications

16
Figure 13 – Heat Medium Piping
CAUTION
1. DO NOT EXCEED 30 – 120% OF
STANDARD HEAT MEDIUM FLOW.
2. DO NOT EXCEED 85.3 PSI (588 kPa) IN THE
HEAT MEDIUM CIRCUIT AT THE
ABSORPTION CHILLER.
3. DO NOT INSTALL ANY VALVES IN THE
EXPANSION LINE.
The key device required for the proper
operation of the unit is a Heat Medium
Bypass Valve. When the unit requires heat
medium, it will send a signal to this valve to
open. When the unit does not require heat
medium, for whatever reason, this valve will
be commanded to move into bypass
position.
Figure 14 – Heat Medium Bypass
Valve (HMV) Installation
Valves and actuators are available in
accessory kits and those kit items are used
in the illustration in Figure 14. The fact that a
particular brand or type of valve and actuator
is used in the accessory kit should not be
taken as an endorsement or preference for
the brand of components used in the
accessory kit. Specific wiring instructions
are included in the accessory kit.
A balancing valve should be installed at
the heat medium outlet to facilitate flow rate
adjustments. An isolation valve should be
installed at the heat medium inlet and must
remain fully open at all times when the unit is
intended to operate.
A balancing valve, usually a ball valve,
should be used in the bypass line. This
valve should be used to set the pressure
drop through the bypass line to be equal to
the pressure drop through the heat medium
circuit of the unit.
AFTER LEAK TESTING, insulate the
piping to help prevent heat loss. Ensure that
all stop valves, balancing valves, and
thermowells are accessible.
FREEZE PROTECTION
When the chiller/chiller-heater and/or
associated piping are installed in a location
that may be subjected to freezing conditions,
appropriate freeze protection steps must be
taken. Many methods are available but the
most common method is the use of glycol.
Glycol may be permitted for use in Yazaki
chiller-heaters with certain precautions:
1. Do not use automotive glycol (Antifreeze) since
it may contain chemical additives that could be
inappropriate and potentially damaging to the
Yazaki chiller-heater. Use only glycol
appropriate for use with copper tubing and
brass fittings.
Exception: The heat medium circuit is
constructed of stainless steel so glycol used in
this circuit must not corrode that material.
There is no copper or brass in this circuit.
2. Do not exceed a mixture of 50% by weight.
3. Be aware that loss of performance will result
when glycol is used. The impact can become
very significant.
4. Propylene Glycol is preferred over Ethylene
Glycol. There is little difference in anti-freeze
characteristics, PG is non-toxic, and PG is
also less viscous than EG, reducing the
required pump power.
5. Use of glycol can cause the unit to operate at
higher internal temperatures. This may cause
faster depletion of inhibitor than what may be
perceived as normal.