General Operation - Lochinvar Power-fin 502 Service Manual

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Service

General Operation

How the appliance operates
The Power-fin uses a copper-finned tube heat exchanger to
transfer heat from the flue products to the water. An electronic
control module monitors various inputs to initiate a call for
heat. The blower provides both primary and secondary air to
the burner and forces the flue products out of the combustion
chamber and into the vent system.
regulates the blower speed (on B9 and M9 models) to control
the firing rate of the appliance. The modulating gas valve
monitors the amount of combustion air being pulled into the
blower and regulates the amount of gas supplied, which then
mixes with the combustion air and is supplied to the burner.
How the control module operates
The Power-fin control module receives input from appliance
sensors. The control module activates and controls the blower
and gas valve to regulate heat input and switches heater, DHW
and system pumps on and off as needed. The user/installer
programs the module to meet system needs by adjusting control
parameters. These parameters set operating temperatures and
heater operating modes. Appliance operation can be based on
heater outlet water temperature, heater return water
temperature, system supply temperature, system return
temperature or tank temperature, depending on the parameter
setting.
Sequence of operation
Table 1A shows control module normal sequences of operation
for space heating and DHW operation.
operation sequence is for a typical application, programmed to
provide DHW priority.
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Access modes
User
The user can adjust space heating set point using the UP and
DOWN buttons at any time during normal operation. By
entering the USER code (0704), the user can also change
temperature units, time and date, and night setback settings. In
The control module
user mode, the following parameters can be viewed but not
changed: Heater outlet water temperature in DHW mode;
heater model number; software version; total operating hours,
and total cycles.
Installer
Most parameters are available only to the installer, accessible
only by entering the installer access code (5309).
Saving parameters
To save parameters and exit programming:
Press the ENTER/RESET button, then the MENU/EXIT button
3 times.
To keep parameter settings only for a current operating cycle:
Press the MENU/EXIT button 3 times after making all desired
parameter changes.
To enter a parameter and continue programming:
Press the MENU/EXIT button 1 time to return to the parameter
listings; press again to return to the menu listings. Remember to
The combined
press the ENTER/RESET button when finished programming in
order to save the changes made.
Service Manual