AERCO C-More Controls Manual June 2010 - Manual (Page 92)

C-More Controller for Benchmark, Innovation & KC
USER MANUAL
Page 92 of 162 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 04/22/14
GF-112 Phone: 800-526-0288 OMM-0032_0E
8.3 WHM PRINCIPLES OF OPERATION
The WHM system communicates with the plant water heaters via a RS485 network utilizing
Modbus RTU protocol (8 bit, 9600 baud, no parity). All Modbus networks are implemented using
a Master/Slave scenario where only one device, the Master, can initiate a communication
sequence. All other C-More equipped units on the network are called Slaves. However, since
the WHM software code resides in each C-More that is part of the system, any one of the C-
Mores can be selected to control the system.
The controlling Master monitors the Air/Fuel Valve position (VP) of all enabled units. When this
valve position (% open) exceeds a user-selectable limit (WHM Nxt On VP), the WHM will open
the sequencing valve of another water heater in the system. Conversely, when the valve
positions of all enabled units have dropped below a different user-selectable limit (WHM Nxt Off
VP) threshold, the WHM will close the sequencing valve on a unit. The philosophy behind this
approach is to maintain the fire rates (Air/Fuel Valve % open) at a level that maximizes heater
efficiency.
In addition to collecting Air/Fuel Valve position data, the controlling Master also monitors the
total accumulated operating time for each unit on the system and attempts to balance the
system so that all units operate for approximately the same number of hours.
8.4 WHM MENU
The WHM Menu in each C-More can only be viewed when the Unit Type option in the
Configuration Menu is set to Innovation WH. The WHM Menu items are protected by Password
Levels 1 and 2. Level 1 protects user menu items and Level 2 protects menu items used by
Factory-Trained personnel. The WHM Menu options are listed in Table 2-4. Descriptions for
each of these menu items are included in Section.3, Table 3-1.
8.5 HARDWARE INSTALLATION & SET-UP INSTRUCTIONS
The following paragraphs provide the basic installation and set-up instructions for implementing
a Water Heater Management System (WHM) to control up to eight (8) AERCO Innovation Water
Heaters. Some of the descriptions and procedures included in Chapter 2 may be repeated here
to avoid unnecessary referencing.
8.5.1 Hardware Installation
All Innovation Water Heaters which will be controlled by a WHM master must be equipped with
an actuator-controlled sequencing valve (part no. 92093). This valve is installed on the cold
water inlet as shown in Figure 8-2.