Raypak MVB 503-2003 - Manual (Page 34)

34
Definitions
% OUT - Current percent modulation rate of heater.
BOIL DSGN - Design boiler water temperature used in
heat loss calculations.
BOIL MASS - This setting allows adjustment in the
field for high or low thermal masses; High thermal
mass (setting=3) provides slower reaction, lower ther-
mal mass (setting=1) provides faster reaction.
BOIL MAX - Highest outlet water temperature that the
control is allowed to use as a target temperature.
BOIL MIN - Lowest outlet water temperature that the
control is allowed to use as a target temperature.
BOIL ON - Accumulated runtime of heater (up to 999
hours, then resets to 0).
BOIL OUT - Actual heater outlet water temperature.
BOIL START - Starting boiler water temperature.
BOIL SUP - Actual system supply water temperature.
BOIL TARGET - Target temperature that the heater is
trying to maintain.
‘BURNER’ DELAY - Holds control output at ignition
setting from the start of the ignition sequence to the
specified burner delay time (0 to 3:00 min.).
DEM 1 - Indicates 24 VDC signal has been supplied to
the H+D terminal.
DEM 2 - Indicates 24 VDC Flame Proof signal is pres-
ent.
DIFF - The operating differential of the heater; The
heater outlet water temperature is allowed to rise
above the BOIL TARGET temperature by 1 ⁄
2
of this dif-
ferential before the heater shuts off. For example, if
the heater target temperature is set to 160°F (71°C)
and the differential is set to 10°F (5°C), on temperature
rise, the heater will shut off at 165°F (74°C). Once the
heater shuts off, it will not come on again until the tem-
perature falls to 155°F (68°C).
EXTERNAL INPUT SIGNAL – Selects external input
signal range (0-10VDC or 2-10VDC):
0-10VDC or 0-20 mA external input signal – When
the 0-10VDC signal is selected, an input voltage of 1
VDC corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 VDC corresponds
to a boiler target temperature of 220°F (104°C). As the
voltage varies between 1 VDC and 10 VDC, the boiler
target temperature varies linearly between 50°F
(10°C) and 220°F (104°C). If a voltage below 0.5 VDC
is received, the boiler target temperature is displayed
as “– – –” indicating that there is no longer an internal
call for heat. A 0-20 mA signal can be converted to a 0-
10 VDC signal by installing a 500 Ω resistor on the
external input signal device’s terminals.
2-10VDC or 4-20 mA external input signal – When
the 2-10VDC signal is selected, an input voltage of 2
VDC corresponds to a boiler target temperature of
50°F (10°C). An input voltage of 10 VDC corresponds
to a boiler target temperature of 220°F (104°C). As the
voltage varies between 2 VDC and 10 VDC, the boiler
target temperature varies linearly between 50°F
(10°C) and 220°F (104°C). If a voltage below 1.5 VDC
is received, the boiler target temperature is displayed
as “– – –” indicating that there is no longer an internal
call for heat. A 4-20 mA signal can be converted to a 2-
10 VDC signal by installing a 500 Ω resistor on the
external input signal device’s terminals.
FP - Flame proof warning.
MODE - Operating mode of the heater.
OFFSET - The Offset setting allows the boiler target
temperature to be fine tuned to the external input sig-
nal. The control reads the external input signal and
converts this to a boiler target temperature. The Offset
setting is then added to the boiler target temperature.
OUTDR - Outdoor air temperature.
OUTDR DESIGN - Design outdoor air temperature
used in the heat loss calculation.
OUTDR START - Starting outdoor air temperature.
PUMP DLY - Sets the operating time of the pump once
the CFH is satisfied.
TANK - Current DHW tank temperature (Mode 3).
TANK DIFF - Storage tank differential (Mode 3).
TANK TARGET - Target temperature in the DHW
storage tank (Mode 3).
UNITS - Selects the temperature units to be displayed
(°F or °C).
NOTE: The defined terms are not active in all
modes of control operation.