Lochinvar 000 - 500 User Manual
5. Make sure good mechanical connections are made to
the sensor, any interconnecting wiring and the
controller.
controller.
6. Do not mount sensor with leadwire end pointing up in
an area where condensation can occur.
7. Use shielded wiring to connect the sensor to the control
when the possibility of an electrically noisy
environment exists. Shielded cable is recommended on
all cable runs of more than 25 feet in length.
environment exists. Shielded cable is recommended on
all cable runs of more than 25 feet in length.
Outdoor Air Reset Option
For boilers ordered with the Outdoor Air Reset option,
there is an additional control (FIG. 29). There are three
setting knobs for Shutdown, Outdoor Air Max., and Ratio.
There is also a switch to turn the outdoor air shutdown
feature On or Off. An O.A. Sensor is also included.
For boilers ordered with the Outdoor Air Reset option,
there is an additional control (FIG. 29). There are three
setting knobs for Shutdown, Outdoor Air Max., and Ratio.
There is also a switch to turn the outdoor air shutdown
feature On or Off. An O.A. Sensor is also included.
FIG. 29 Optional Outdoor Air Reset Control
Shutdown
The Shutdown knob specifies the outdoor air lockout
temperature at which the control would prevent the unit
from operating.
The Shutdown knob specifies the outdoor air lockout
temperature at which the control would prevent the unit
from operating.
Outdoor Air Max (O.A. Max)
The O.A. Max knob allows a reset up to the maximum
outdoor air temperature specified by this knob setting.
When the outdoor air temperature is above the specified
setting, the unit will not function in the O.A. Reset Mode,
but will continue to run at the selected set point
temperature.
The O.A. Max knob allows a reset up to the maximum
outdoor air temperature specified by this knob setting.
When the outdoor air temperature is above the specified
setting, the unit will not function in the O.A. Reset Mode,
but will continue to run at the selected set point
temperature.
Note that the set point knob will now indicate the
“minimum” boiler temperature. Target temperature is
determined by the ratio and outdoor air temperature below
the O.A. Max setting.
“minimum” boiler temperature. Target temperature is
determined by the ratio and outdoor air temperature below
the O.A. Max setting.
Ratio
The Ratio knob allows control over the reset ratio to be
used during Outdoor Air Reset. The allowable ratios are as
low as 0.5:1 or as high as 1.5:1.
used during Outdoor Air Reset. The allowable ratios are as
low as 0.5:1 or as high as 1.5:1.
Selecting the 0.5:1 ratio will increase the set point 0.5° for
every 1.0° drop in outdoor air temperature up to the
maximum set point temperature.
every 1.0° drop in outdoor air temperature up to the
maximum set point temperature.
Selecting the 1.5:1 ratio will increase the set point 1.5° for
every 1.0° drop in outdoor air temperature up to the
maximum set point temperature.
every 1.0° drop in outdoor air temperature up to the
maximum set point temperature.
If the outdoor design and boiler design temperatures are
known, the Ratio setting can be calculated using the
following formula:
known, the Ratio setting can be calculated using the
following formula:
Ratio = (boiler design temperature - operator set point)
(O.A. Max. setting - outdoor design temperature)
Note that the reset set point cannot exceed the maximum
set point of the boiler thermostat.
set point of the boiler thermostat.
These settings are illustrated graphically in Figure 30.
FIG. 30 Outdoor Air Control Example Chart
Outdoor Air Shutdown Enable/Disable Switch
The Outdoor Air Shutdown Enable/Disable switch turns
the outdoor air shutdown feature On and Off. Disabling the
Outdoor Air Shutdown feature allows the unit to operate
regardless of the outdoor air temperature. This is needed
for indirect domestic hot water systems for example.
The Outdoor Air Shutdown Enable/Disable switch turns
the outdoor air shutdown feature On and Off. Disabling the
Outdoor Air Shutdown feature allows the unit to operate
regardless of the outdoor air temperature. This is needed
for indirect domestic hot water systems for example.
High Water Temperature Limit Con trol
The appliance is supplied with a fixed setting, auto-reset
high water temperature limit control. The setting of this
control limits max i mum discharge water tem per a ture. If
water temperature exceeds the setting, the limit will
break the con trol circuit and shut down the appliance.
The limit control will only be reset after the water tem -
per a ture has cooled well below the setting of the limit.
The auto-reset high water temperature limit control is
mount ed in the outlet side of the front header.
The appliance is supplied with a fixed setting, auto-reset
high water temperature limit control. The setting of this
control limits max i mum discharge water tem per a ture. If
water temperature exceeds the setting, the limit will
break the con trol circuit and shut down the appliance.
The limit control will only be reset after the water tem -
per a ture has cooled well below the setting of the limit.
The auto-reset high water temperature limit control is
mount ed in the outlet side of the front header.
22
OUTDOOR AIR RESET OPTION
R4R
4
R6R
6
R8R
8
R16R
1
6
R15R
1
5
C7C
7
C9C
9
C10C
1
0
VR2
VR2
VR3
VR3
OJ1
OJ1
OJ2
OJ2
D4D
4
J4J
4
CN1
CN1
CN2
CN2
CN9
CN9
CN7
CN7
CN8
CN8
CN3
CN3
CN4
CN4
CN5
CN5
CN6
CN6
W1
W1
TST2314
TST2314
20
20
15
15
10
10
5
5
(F-)0
(F-)0
15
15
14
14
13
13
12
12
11
11
10
9
9
8
8
7
7
6
6
5
5
OFF
OFF
120
120
240
240
220
220
200
200
160
160
140
140
SETPOINT
SETPOINT
DIFFERENTIAL
DIFFERENTIAL
HIGH-FIRE
HIGH-FIRE
OFFSET
OFFSET
(c)2002 L.C.
(c)2002 L.C.
SHUTDOWN
45
50
45
1.3
O.A. MAX.
70
40
VR1
65
RATIO
VR2
0.6
0.5
0.7
1.4
1.5
W1
W2
W3
60
50
70
40
55
60
VR3
65
DISABLE
O.A. SHUTDOWN
1.0
0.9
0.8
1.2
1.1
O.A. SENSOR
ENABLE
ON
SW1
55
CN1
Ground the cable shield at the connection to the boiler
temperature control only. Do not ground the shielded
cable at the sensor end.
temperature control only. Do not ground the shielded
cable at the sensor end.
To maintain temperature accuracy, sensor wires should
be 18 AWG two conductor (18/2). Use shielded wire if
required.
be 18 AWG two conductor (18/2). Use shielded wire if
required.
NOTE:
ADDITIONAL TEMPERATURE
CONTROLS