Instruction manual

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P/N HN-IOM-1 82-0331 Copyright 2009 Mestek, Inc.
Finned copper tube gas boilers & water heaters – Control manual
Menu item Under . . . Explanation
FIRMWARE VERSION
V X.XX
All boilers in a multiple boiler application should preferably have the same firmware version
to ensure consistency. If versions are different, they must all have the same first digit in the
version number (i.e., 3.x).
# OF BOILERS
BOILERS
Display only — shows the number of boilers detected on the network for a HeatNet network
only; displays the total number only on the Master boiler; displays “1” for MEMBER boilers or
for any boiler not on a HeatNet network.
The maximum number of boilers on a HeatNet network is 16.
LEAD BOILER #
BOILERS
Sets the boiler that starts first in multiple-boiler systems.
HEAT BAND
BOILERS
The heat band is the height of the modulating
band. When the water temperature is between
½ the heat band above or below the setpoint
temperature, boiler firing rate modulates.
Boilers are at minimum input at the upper end
of the band and maximum input at the lower
end of the band. Boilers come on only if the
water temperature is below the band. Boilers
stage off when the water temperature is above
the band.
HEATNET BOILERS
BOILERS
This line appears on the display only for a HeatNet Master boiler (boiler with a sensor
connected to the SYSTEM HEADER sensor input terminals). The line is blank on MEMBER
boilers.
If the number of boilers shown is less than the number of boilers on the HeatNet network,
check the yellow light on the HeatNet connection port of each boiler. The yellow light will be
ON if the communications port is successfully connected to the Master.
The address of each recognized MEMBER boilers (addresses 2 up to 16), and begins with “1,”
the address of the Master boiler.
LOCAL SETPT OR
SYSTEM SETPT
SETPOINTS
Setpoint temperature controlled by the HeatNet control.
Local setpoint refers to boiler supply temperature. System setpoint appears if there is a sensor
connected to the SYSTEM HEADER sensor terminals. System setpoint refers to the header
temperature.
NOTE: If the boiler is operated by a Master control or by a remote control (building
management system, 4-20ma control, etc.), this setpoint temperature only comes into play
when the HeatNet control is in override mode (such as by closing its Heat Demand, AA or T1,
T2 terminals; or by the 4-20mA Enable if 4-20mA is set to Highest Priority).
OPERATE LIMIT
SETPOINTS
This is for boilers regulating header temperature instead of boiler supply temperature, or
boilers operated by an external source, such as by a Master boiler on a HeatNet network or
by external 4-20mA signal or closure on T1,T2 or AA. OPERATE LIMIT is the temperature at
the boiler outlet that will cause the boiler control to shut down on high temperature limit. It
must be high enough above the upper end of the heat band to avoid nuisance cycling. For
boilers operating as stand-alone and regulating boiler supply temperature, this setting is not
necessary, because the boiler shuts off when the SUPPLY temperature exceeds the top of the
HEAT BAND.
The maximum setting is 220°F.
Example: If the boiler setpoint is 180°F, and the heat band is 30°F, the upper end of the heat
band is 180 + 30/2 = 195°F. The limit band (see below) must be set at 10°F so the OP LIMIT
setting can be: 195 + 10 = 205°F. The OP LIMIT cannot be higher than 220°F.
The operating limit setting (OPERATE LIMIT) always limits boiler outlet water temperature,
regardless of how the boiler is controlled (HeatNet member, 4-20ma control, stand-alone or
other).
The OP LIMIT BAND (see below) determines when the boiler begins to be forced to reduce
input as the outlet temperature rises toward the limit setting.
Setup menus — parameter explanationsTable 9
Control menus and adjustments (continued)
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