Staging Process; Service And Maintenance; Troubleshooting - Crown Boiler PHNTM080 Installation Instructions Manual

vi. Recovering – Boiler is attempting to return to the "Available" state (for example, this state is shown when
the slave is in post purge or powered down).
• Lead – Lead boiler is shown.
% - If the boiler is firing in response to a call from the Master, this is the percentage of maximum fan speed at
•
which the boiler is operating. Normally this value will wither be zero or equal to the Target System Rate.
d) Master Demands - Shows the current status of the thermostats connected to the Master. This screen also identifies
the source of the set point value currently in use by the Master.
e) Outdoor Reset Screens (only visible when outdoor reset has been enabled in Configuration Menu):
• Outdoor - Current temperature at outdoor sensor.
• Setpoint - Current CH set point obtained from outdoor reset curve (Figure 7.9).
• Supply (or Header) Temperature - The actual water temperature at the current set point location (either the
boiler supply or header, depending on the demand and what set point location was selected in the Configuration
Menu).
f) Outdoor Reset Graph - Shows all outdoor reset curve settings, the current outdoor temperature, and set point.
Note: this graph is for reference only and does not scale.
The Master uses the following basic rules to add, drop, and modulate Slaves:
1) If the header temperature is at least 5 degrees below set point, the Master will initiate a call for the lead boiler to fire. The
master will direct the lead boiler to operate at an input corresponding to 70% of maximum fan speed or less.
2) The Master decides when to add the next boiler based on a combination of time and the set point error (i.e. the difference
between current and set point temperature). In general, either of the following requirements must be met to add another
boiler:
• The error must be at least 5F below set point with all previous stage(s) operating at 70% of max input for at least 3
minutes. OR:
• The previous stage(s) has been operating at 70% of max fan speed continuously for 20 minutes.
Once the next stage has been added, the target input is divided evenly among all stages. For example, if one boiler is
operating at 70% of full input, and the next stage is added, the target rate of both boilers will be 35% immediately after
the second boiler is added.
3) The fan speed of each boiler is limited to 70% of maximum until all boilers are firing.
4) Once all boilers are firing, they are permitted to operate at higher fan speeds. All boilers operate at same fan speed with
this speed determined by the Master using a "PID" algorithm. This algorithm is similar to that used to control modulation
on a single boiler and is based on the size, duration, and rate of change of the set-point error.
5) If the output of all operating boilers exceeds the current heating load, they will modulate down together until either the
heating load is matched or the minimum fan speed is reached. Once all operating boilers are at their minimum fan speed,
the Master will drop one stage if either of the following is true:
• The header temperature has been at least 5F above the set point temperature for at least one minute. OR:
• All operating boilers have been at their minimum fan speed for 20 minutes.
6) Boilers are added in order of their address. For example, if the current lead boiler is 2, the next boiler to come on will be
3. If a boiler fails to respond to a demand from the Master after 2:45s, the Master will transfer the demand to the boiler at
the next higher address. Boilers are dropped in the reverse order.
7) The Master boiler is also a Slave and sends demands to itself using the same rules as it does for any other boiler. If the
Master enters a hard lockout, it will attempt to continue managing the multiple boiler system while keeping itself in the
disabled state.
Refer to Section XIII of the Phantom 080-180 installation manual provided with the boiler for service and maintenance
instructions.
Refer to Section XIV of the Phantom 080-180 installation manual provided with the boiler for troubleshooting instructions.
F. Staging Process
VIII Service and Maintenance
IX Troubleshooting
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