Raypak MVB 503-2003 - Manual (Page 31)

31
Mode 3 – Dedicated DHW operation using UniTemp
80 piping. A call for heat is determined by the DHW
sensor and the DHW boiler target. The heater outlet
water is also controlled to the boiler target tempera-
ture. See Fig. 32.
Mode 4 (Not supported) – Outdoor reset using pri-
mary piping. The heater is operated as in Mode 1.
However, the target temperature is based on outdoor
reset.
MODULATING
*
Fig. 31: Mode 2 Primary/Secondary Piping
MODULATING
Fig. 32: Mode 3 Dedicated DHW
*Maximum 4 times the pipe diameter or 12”, whichever is less.
Mode 5 – Outdoor reset using primary/secondary pip-
ing. The heater is operated as in Mode 2. However, the
target temperature is based on outdoor reset. See Fig.
33.
Mode 6 (Not supported) – Designed for an external
input signal with primary piping. The external input sig-
nal can be provided from a BMS, an EMS or a
sequencing control. The external input signal changes
the boiler target according to a linear scale. The con-
trol operates the boiler burner to maintain the boiler
target at the boiler outlet sensor.
Mode 7 – Designed for an external input signal with
primary/secondary piping. The external input signal
can be provided from a BMS, an EMS or an external
control. The external input signal changes the boiler
target according to a linear scale, as shown in Tables
O and P. The control operates the boiler burner to
maintain the boiler target at the system sensor. See
Fig. 34
MODULATING
*
Fig. 33: Mode 5 Primary/Secondary Piping with
Outdoor Reset
*Maximum 4 times the pipe diameter or 12”, whichever is less.