Pressure Monitoring System (PMS)
Cross Contamination Protection
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BA HERCS’ Pressure Monitoring System (PMS) is an alternate method to a double wall application, and is ideal in a facility which is serious about cross contamination. The PMS is a series of components used to secure the potable water system by isolating that side of the heat exchanger. The PMS can be used with either water to water or steam to water as long as there is at least a 40 psi (2.7 bar) difference between the primary and secondary sides of the heat exchanger. When pressure increases in the lower side of the heat exchanger the non-electric, self acting pressure valve closes off the inlet of the primary side, the control valve, and the inlet of the secondary side. On both outlets there is a tight closing check valve that will not allow fluid to back feed into the heat exchanger. On the lower connection of the low pressure side of the heat exchanger is a blow down valve set at 10 psi (0.7 bar) above the actual pressure. This will drain the heat exchanger. With the control valve closed and the heat exchanger draining, there will be no heat transfer and the DHW is isolated, therefore, no cross contamination will occur. This also produces cold water at the outlets causing the proper authority to be contacted so that the proper repairs can be made. List of components Pressure sensitive shut down actuator on the control valve. Pressure sensitive shut down valve on the cold water inlet. Tight close off check valves on both outlets. A pressure sensitive blow down valve is located on the outlet of the low pressure side. All components are non electric and self acting.
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