HydroTherm HeaetNet V3 KN-10, User Information

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CONTROL METHODS HeatNet Control V3 2.x
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Not Preferred:
Example of having a larger Base Load boiler that is not of
the modulating type: If there is a 6 Million BTU Base Load
boiler running with (3) 2 million BTU HeatNet boilers, a
short cycling situation will arise when the (3) 2 million BTU
boilers are running @ 95% and the Base Load boiler is
called on. At this point there is a need for approximately 6
million BTUs. The (3) smaller boilers will then modulate
down to low fire. At this point, the (3) smaller boilers need
to shut off or the Base load boiler would need to shut off.
There is no overlap. A selection for stopping the boiler now
needs to be determined. Setting the Stop qualifier;
Modulation to 40% or a low fire rate will shut the Base
Load boiler off and allow the (3) smaller boilers to modulate
up again (short cycle of the Base Load boiler; Use the Delay
Timer and Min OFF timer). The Stop qualifier; OA T >
xxF may also be used if the system design temperature is
known. Then let the Base Load boiler cycle off of its limits,
whether a 2 stage, Hi/Lo, or modulating boiler. The default
setting is for the Base Load boiler to stop first once the
water temperature
exceeds the top of the heating band.
Figure 16 Base loading relay
Base Load RIB Relay
24 VAC
24 VAC Return, or
Chassis Ground
Enable Input on
Base Load Boiler
1. First ensure that the ADVANCED
SETUP:SYSTEM:OPTION: is set to BASE
LOAD. The Base Load Relay (K8) will not be
enabled/used unless this is selected.
2. Now, The ADVANCED SETUP:BASE
LOAD:BASE LOAD BOILERS: must be set to 1.
3. When the START condition in the BASE
LOAD BOILERS menu is met, the K8 relay will
close. But, only when the DELAY TIME under
the BASE LOAD BOILERS menu expires.
Base Load Relay