Crown Boiler PHNTM080 - XII Operation; Operation

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XII Operation
A. General Information
ThisboilerusesthemicroprocessorbasedHoneywellR7910B“boilercontrol”tomanageallboilerfunctionsincludingame
supervisionandmodulation.Twosetpointor“target”boilersupplytemperaturesarestoredinthecontrol’smemory;onefor
space heating (CH) and one for domestic hot water (DHW) production. If an outdoor temperature sensor is connected to the
boiler, and enabled, the space heating supply set point will automatically shift downward as the outdoor temperature increases.
For more information on this feature see the discussion on boiler water reset below.
The control modulates the boiler input by varying the fan speed. As the fan speed increases, so does the amount of gas drawn
into the blower. As a result, a fairly constant air-fuel ratio is maintained across all inputs. The control determines the input
needed by looking at both current and recent differences between the supply temperature and the set point temperature. As the
supply temperature approaches the set point temperature, the fan will slow down and the input will drop. The minimum input is
approximately 1/5 of maximum input.
Thisboilercontrolalsomonitorsboilerreturnanduetemperatures.Inaddition,allothersafetycontrolsareconnectedintothe
R7910B. The R7910B uses inputs from all of these controls to either shut down the boiler when an unsafe condition exists or, in
some cases, to correct the problem.
Finally, the basic boiler control manages up to three pumps:
• Boiler Loop Pump (built into boiler)
• DHW pump
• System pump
Refer to the Piping Section for the location of these pumps
The touch screen display on this boiler has three basic functions:
1) To allow the professional HVAC technician to set-up this boiler so that it will work properly in the system to which it is
connected.
2) To indicate the current status of the boiler and to provide information that will assist the professional HVAC technician in
solving problems with the boiler and/or system.
3) To advise the homeowner if there is a problem which requires professional service.
A map of the basic menu structure is shown in Figure 12.0. In order to prevent unauthorized or accidental adjustments, access
to menus, which change settings and boiler operation, is password protected. In general, if a menu is not touched for 255 seconds,
the display backs up to the previous menu. Once the Home Screen is returned to, the password must be reentered in order to
regain access to protected menus (this feature prevents the boiler from being permanently left in operation without password
protection).
B. Conguring the Control
UsetheCongurationMenutoprovidetheboilerwithbasicinformationaboutthetypeofsystemtowhichitisconnected.On a
newinstallationconguretheboilerrst,thengototheSettingsMenutosetparameterssuchastargetwatertemperatures. A map
oftheCongurationMenustructureisshowningure12.1.Toconguretheboiler:
1) From the Home Screen (shown in Figure 12.0) , press “MENU” to enter the Main Menu:
a) Press “CONFIGURE”
b) When prompted for a password, use the “+1” key to raise the password to “005”. Press SUBMIT, then NEXT (if you
accidently scroll past 005, press EXIT to return to the main menu and start over).
c) ReviewtheWarningandpressACCEPTtocontinuetotheCongurationMenu.