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 VAC signal has been supplied to
the H+D terminal.
DEM 2
- Indicates 24 VAC 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
heat demand. 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
heat demand. 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. Warns that the control did
not see burner flame within 5 min. of call for heat.
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).
NOTE:
The defined terms are not active in all
modes of control operation.
California Hot Water Supply, Inc.
(800) 249-7244
34
