Raypak MVB 503-2003 - Manual (Page 32)

32
MODULATING
*
Fig. 34: Mode 7 Primary/Secondary Piping with
External Target Temp
*Maximum 4 times the pipe diameter or 12”, whichever is less.
Mode 8 – This mode is for remote firing control of the
heater via an external sequencer such as the Raypak
TempTracker MOD+. The Boil Max setting is the
heater shutdown temperature (max temperature). The
heater is enabled via dry contact at the Enable/Disable
connection at the low voltage terminal strip, and the fir-
ing rate is controlled by a 0-10 VDC signal from the
external sequencer. A control signal of ≥0.5 VDC
equates to minimum fire, and a signal of 10 VDC
equates to 100% firing rate. See Fig. 35.
NOTE: For Modes 7 and 8, connect to pins 13 and
14 on the low-voltage panel. See page 21. Use these
modes for systems using an external signal.
*
RAYPAK
MODULATING
TEMP CONTROL
OUTDOOR AIR
SENSOR
*Maximum 4 times the pipe diameter or 12”, whichever is less.
Fig. 35: Mode 8 Primary/Secondary Piping with
External Direct Drive