System Description & Sequence of Operation
The Multiaqua MACH (Multiaqua Air Conditioning Heat Pump) is self-contained Reverse Cycle Chiller featuring dual
condenser fans, direct expansion outdoor coil (air side) and a brazed plate liquid solution heat exchanger (liquid side). The
outdoor coil acts as a condenser expelling heat from the refrigeration process in cooling and is an evaporator coil in the
reverse cycle heat pump mode. The MACH utilizes a SporlanTM thermostatic expansion valve (TXV) for the outdoor coil
and a piston type-metering device on the liquid solution heat exchanger. In the cooling mode the outdoor coil (condenser)
expansion/check valve is bypassing liquid refrigerant to the liquid solution heat exchanger (evaporator) metering
device. In the heating mode (reverse cycle) the outdoor coil (evaporator) expansion/check valve is receiving condensed
liquid refrigerant from the liquid solution heat exchanger (condenser) metering device. Integral safety features are included on
all models; including a low water flow control, a refrigerant high and low pressure switch and a five (5) minute delay on
break timer.
The system, depending on which mode has been selected (HEAT or COOL) will provide either a chilled or heated liquid
solution (water and Propylene Glycol mix). The solution temperature is controlled by the liquid solution temperature
control (DTC) which is factory set at 120°/44° (F). The liquid solution is circulated through the heat exchanger by an
internal stainless steel pump, which is protected with Silicon Carbide-Viton Seals, to the system supply piping and to
the airside fan coil/s.
The Pump will not self-prime. A full column of liquid solution is necessary for operation. Do not
attempt to operate the pump without a full charge of liquid solution or seal damage will occur.
If the external load is a series of fan coils, each one must contain an individual zone valve to control the liquid flow. The zone
valves are selected to provide the flow rate needed to achieve the proper capacity from the fan coil they control.
The temperature of the circulating liquid solution is controlled for either mode by a two (2) stage DTC (digital temperature
control) with adjustable set points for precision control. A system sequence of operation, individual control description,
troubleshooting information and a schematic are included in the controls section of this manual.
The liquid solution piping system suggested for new installations is a composite piping system. The composite system
delivers easy on installation, low-pressure drops and will not rust or corrode. Existing and new copper or ferrous piping
systems are adaptable to the Multiaqua system.
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