GF-135
Esteem 399 Low NOx Boiler
Chapter 18
OMM-0089_0A
Installation, Operation & Maintenance Manual Controller Operation
Page
162
of
188
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0089_0A
MC1 06/19/14
Ph.: 800-526-0288
NOTE
Stable cascade operation requires that all boilers in a cascade
System be the same size. Mixing boiler sizes in a cascade System
could lead to temperature fluctuations and erratic cascade
operation.
18.9.8 CH or DHW Boilers (Default: 0)
The CH or DHW Boilers setting specifies how many boilers in a Split Cascade System will
respond to a domestic hot water call. The CH or DHW Boilers always include the Master boiler.
The remaining boilers will only respond to central heating calls. This allows the Cascade System
to satisfy both central heating and domestic hot water calls at the same time. At the completion
of a domestic hot water call, the CH or DHW Boilers will again be available to respond to central
heating calls. Press the LEFT or RIGHT buttons to adjust the CH or DHW Boilers setting then
press the OK button to store the setting.
Figure 18-59: Maximum Firing Rate Menu
NOTE
Splitting the cascade System into CH only and CH or DHW boilers
requires the boilers to be piped as shown in Figure 18-48
.
The CH
or DHW boilers must be piped to both CH and DHW loads directly
for proper operation.
NOTE
DHW Priority must be set to Enabled in DHW Settings of the
cascade Master for proper operation.
NOTE
All CH or DHW Boilers will respond to a domestic hot water call. It
is important that the domestic load is capable of transferring all of
the heat generated to prevent excessive boiler cycling.
