SmartPlate EV Installation, Operation and Maintenance Manual
CHAPTER 3
– FUNCTIONAL DESCRIPTION
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FUNCTIONAL DESCRIPTION
3.1 INTRODUCTION
SmartPlate EV Water Heaters are equipped with a double-wall, stainless steel brazed plate heat
exchanger, an ECS II Electronic Control System, and a 3-Way 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 EV Water Heaters include:
•
Boiler water and domestic water Y-strainers with blow-down valves
•
Relief Valve
•
Isolation valves
A simplified functional block diagram for the SmartPlate EV Water Heater is shown in Figure
3.4, below. 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 Flow Meter.
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. The flow meter
measures the flow rate of the incoming water, 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 Control Valve, located
in the inlet path of the boiler water piping connection. If desired, the Control Valve configuration
can be changed to a 2-Way Valve by capping off the return to the boiler side of the 3-Way Valve
(see Figure 3.4. 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).
The brazed plate heat exchanger
’s 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.
3.3 ELECTRONIC CONTROL OVERVIEW
The primary control mechanism for the ECS II is a Temperature Controller which is installed in
the Control Box. The Controller utilizes feed forward and PID (Proportional Integral Derivative)
algorithms to provide precise control of the
unit’s outlet temperature. Outlet temperature control
is accomplished by modulating the open/closed position of the 3-Way Control Valve Actuator.
