Raypak VERSA IC, Инструкция по установке и эксплуатации

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“Limp-Along” Operation
of PIM™
The VERSA IC
®
PIM™ is fully capable of “limp-along”
operation of the heater should anything happen to the
VERSA
®
Control board or the communications
between the PIM™ and VERSA
®
Control board.
The Operator Set-point potentiometer on the PIM™
(see Figure 41) is used to control the Operating
Setpoint at the outlet sensor during limp-along opera-
tion. This is the target outlet temperature used in the
firing rate calculations. The maximum target setpoint
will be limited to H models of XFyre 192°F, XPak-FT
192°F, MVB / XTherm 220°F. WH models of XFyre
160°F, MVB/XTherm 180°F regardless of the poten-
tiometer position.
The PIM™ calculates the required firing rate or stage
demand using the heater inlet and outlet sensor inputs
and the target setpoint from the operator potentiome-
ter setting. The algorithm uses the boiler mass and
other parameter settings to refine the firing rate for
optimal setpoint control. Full auto-differential capabil-
ity is retained when enabled using DIP switch #1 on
the PIM™.
The PIM™ will respond to a DHW call signal on the
field wiring terminals. The DHW pump is activated and
the temperature is controlled to the operating setpoint
of the potentiometer. The boiler pump will be activat-
ed whenever there is a Call For Heat to satisfy target
temperature.
Limitations During PIM™
“Limp-Along” Operation
1. Diagnostic information is limited to the alarm relay
and red LED flash codes on the PIM™, and will
only be displayed if the VERSA
®
board on the unit
has failed.
2. System Sensor operation is NOT supported.
3. DHW Sensor operation is NOT supported.
4. Outdoor Sensor and Outdoor Reset functions are
NOT supported.
NOTE: The PIM™ reverts to “limp-along” operation
whenever communication with the VERSA
®
Control
Board is lost for more than 30 seconds or if the
VERSA
®
Control is not found on the communications
bus during power up.
POTENTIOMETER
Fig. 43: PIM™ Potentiometer Location