Table of Contents
Advertisement
SECTION 6 STANDALONE MODES OF OPERATION
To enable the Direct Drive mode:
Main Menu → Advanced Setup → Unit →Application
1.
Go to:
2. Press SH Operating Mode parameter and choose Direct Drive.
3. The Remote Signal parameter now appears. It can be set to one of six options: 4-20mA, 1-5V, BAS,
0-20mA, Network, or 0-5V.
If Network was selected in the previous step, the Unit Address parameter appears. Enter a valid Comm
address. Refer to the Edge Controller Communication Manual (OMM-0140) for information.
6.5 Combination Control System (CCS)
NOTE: The ACS can be utilized for a Combination Control System.
A Combination Control System (CCS) is one that uses multiple boilers to cover both space-heating and
domestic hot water needs. The theory behind this type of system is that the maximum space-heating
load and the maximum domestic hot water load do not occur simultaneously. Therefore, boilers used
for domestic hot water are capable of switching between constant setpoint and ACS control.
For a typical CCS, an adequate number of boilers are installed to cover the space-heating load on the
design-day. However, one or more units are used for the domestic hot water load as well. These boilers
are the combination units and are referred to as the combo boilers. The combo boilers heat water to a
constant setpoint temperature. That water is then circulated through a heat exchanger in a domestic
hot water storage tank.
Only the AERCO Control System (ACS) is necessary to configure this system if only a single valve is used
to switch from space heating to domestic hot water. However, the ACS Relay Panel is required in
combination with the ACS when there are up to two isolation valves, boiler interlocks, and/or a
Domestic Hot Water (DHW) pump in a Combination heating plant where AERCO boilers are being used
for both Building Heat and Domestic Hot Water heating.
The following two options are available for using a combination system; one that uses only the ACS, and
one that requires the optional ACS Relay Box:
•
OPTION 1 - This option is selected when the ACS controls a boiler plant containing up to eight
combination boilers that are Domestic Hot Water Priority (DHW PRIORITY) boilers, along with
building heat (BLDG HEAT) boilers, and one hydronic isolation valve in the main header between the
BLDG HEAT boilers and the DHW PRIORITY boilers.
•
OPTION 2 – When this option is selected, the ACS Relay Panel must be used in conjunction with the
ACS. For this option, the ACS controls a boiler plant containing up to eight combination boilers that
are divided up into Building Priority (BLDG PRIORITY) boilers and Domestic Hot Water Priority (DHW
PRIORITY) boilers, along with building heat (BLDG HEAT) boilers, and using two hydronic isolation
valves in the main header, one between the BLDG HEAT and BLDG PRIORITY boilers, and the other
between the BLDG PRIORITY and the DHW PRIORITY boilers.
In Option 2, when the space-heating load is such that when all the space-heating boilers are at the 100%
valve position, the ACS will then ask the ACS Relay Box for the domestic boilers to become space-heating
boilers. Provided the domestic hot water load is satisfied, the combo (hot water) boilers will then
become space-heating boilers. If the domestic hot water load is not satisfied, the combo boiler(s)
remain on the domestic hot water load. If the combo boilers switch over to space heating, but there is a
call for domestic hot water, the ACS Relay Box switches the combo units back to the domestic load. The
ACS in combination with the ACS Relay Box will ask the BLDG PRIORITY boilers to help with domestic hot
water heating if the DHW PRIORITY boilers are not able to satisfy the domestic hot water demand.
•
Configuration.
•
•
Advertisement
Table of Contents
