OPTIONAL FEATURES
HeatNet Control REV 1.38-1
Page 11
Figure 3
Mixed Boilers: Example: Condensing/Non-Condensing
PRIORITY 1
Condensing (Set)
PRIORITY 2
Non-Condensing (Set)
>FIRING PRIORITY :1
BTU IN 2000,000
CONDENSING YES
MASS MEDIUM
>MODE MIXED
MIN RUNTIME: 10HRs
MIN OFF TIME:
0s
PREDICT START:
YES
FIRING MODE
menu
(master boiler only)
BOILER TYPE
menu
(all boilers in set)
>FIRING PRIORITY :2
BTU IN 2000,000
CONDENSING NO
OIL DIRECT FIRE XXX
BOILER TYPE
menu
(all boilers in set)
Master
In the example
Mixed Boilers: Condensing/Non-
Condensing
., condensing boilers and non-condensing
boilers are used, but other combinations may also be used.
Another example could use (2) small boilers and set them to
Priority 1 and then use (3) larger boilers and set them to
Priority 2. Using these priority settings (with the conditions
menu), the small boilers can run first during the shoulder
months (Spring and Fall) and the larger boilers can fire last
during the colder Winter season (base loading set).
Before the MIXED method can be used, the firing mode on
the Master boiler must be set to MIXED. ADVANCED
SETUP:FIRING MODE: MODE: MIXED. Pressing the
SELECT key when the cursor is pointing to MIXED will
enter the conditions menu. The
START
and
STOP
conditions for starting and stopping the priority boiler set
may be configured here. Temperatures are adjustable.
Once the conditions menu has been entered, the firing order
and stop order of the priority 1 boiler set can be selected
based on up to (3) conditions in the conditional settings
menu. All conditional settings apply to the priority 1 boiler
set. When the conditional settings do not apply to the
priority 1 set, the conditional settings will apply to the
priority 2 boiler set.
Start/Stop Priority Conditions
The following is an example using mixed
condensing and non condensing boilers:
FIRE FIRST
Condensing boilers may be configured to fire first (set to
PRIORITY 1) when:
1.
The Return water temperature is below 140F and
condensing occurs. (The Master’s return water sensor
would need to be moved to the header return.)
2.
The Outside Air Temperature is above a setpoint
determined by the system configuration. This setpoint
ensures that the more efficient condensing boilers run
first during shoulder months (Spring and Fall) when
minimal heating is required. Below this setpoint, larger
boilers should be brought on first to “base load” the
system.
3.
Greater efficiency is required.
STOP FIRST
Condensing boilers may be configured to
stop first
(set to
PRIORITY 1) when:
1.
The Return water temperature is above 140F and
condensing is minimized, thus leaving the larger lower
cost boilers running to carry the load.
S T A R T P R I O R I T Y 1
> S E T : F I R S T
S T O P P R I O R I T Y 1
S E T : O A T < 1 5 ° F
