SmartPlate Installation, Operation & Maintenance Manual
CHAPTER 3
– FUNCTIONAL DESCRIPTION
OMM-0069_0H
• SP-100 • 1/30/2020 Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST Page
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FUNCTIONAL DESCRIPTION
3.1 INTRODUCTION
SmartPlate Water Heaters are equipped with a stainless steel plate heat exchanger, an ECS/SP
Electronic Control System, and an MXG-461 Control Valve. This design results in a highly
responsive system which provides virtually constant hot water flow at the selected setpoint
temperature.
Accessories included with SmartPlate Water Heaters include:
•
Boiler water and domestic water Y-strainers with blow-down valves
•
Relief Valve
•
Air Vent Valve
•
Isolation valves and domestic water drain valve
•
Boiler water differential pressure gauge
•
Domestic water air vent
•
Integral domestic water circulator pump
A simplified functional block diagram for the SmartPlate Water Heater is shown in Figure 3-1.
The following sections provide a top-level functional overview of system operation.
3.2 MECHANICAL OVERVIEW
The cold water enters heat exchanger through the inlet connection, strainer, and mixing box.
Cold water flows through the plate heat exchanger, where it is heated by hot boiler water, and
then discharged through the Domestic Hot Water (DHW) outlet connection. A portion of hot
water is pumped into the mixing box where it is mixed with the cold water entering the heater,
thereby providing a load sensing feed forward function.
Boiler water supplied to the heat exchanger passes through the inlet connection and strainer.
The boiler water heats the colder domestic water, and is then discharged through the boiler
water outlet connection. The boiler water flow is controlled by the 3-way MXG-461 Control
Valve which is located in the outlet path of the boiler water piping connection. If desired, the
Control Valve configuration can be changed to a 2-Way Valve by closing the Ball Valve located
between the boiler water inlet connection and port B of the Valve (see Figure 3-1). However if
this 2-Way configuration is used, ensure that a by-pass line is installed in the boiler water piping
(outside the unit) to avoid dead-heading the boiler water pump.
For SmartPlate models with Double-Wall heat exchangers, heat transfer plates are positioned
together to form one assembly with an air space between them. This protects against leakage of
boiler water into the domestic water. If one of the plates should develop a leak (boiler water or
domestic water, whichever is leaking), the water will enter the air space and exit to the
atmosphere. It will flow out through leak detection channels alerting an operator that a leak has
occurred.
