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direct drive Input Signal
An external heater sequencer provides a positive 0-10
VDC input signal to the controller +V input (terminal
10). The negative VDC signal is applied to the Com/-
input (terminal 9).
The heater remains off while the direct drive input sig-
nal is between 0.0 to 0.5 VDC. An external input signal
of 1.0 VDC or 2.0 mA will energize the heater and then
the firing rate of the unit is based upon the input signal
as indicated in Table D below.
0-10 VDC
4-20 mA
0
1
2
3
4
5
6
7
8
9
10
Table D: 0-10 VDC or 4-20mA External Input (Mode 8)
PUMP OPERATION
The pump is turned on as soon as the direct drive input
signal reaches 0.5 VDC. Once the direct drive input
signal falls below 0.5 VDC, the pump continues to
operate until the Pump DLY purge expires, then the
pump shuts off.
BOILER OUTLET MAXIMUM
TEMPERATURE
The external sequencer is able to operate the heater
temperature. However, the BOIL OUT MAX setting lim-
its the highest temperature at the heater outlet sensor.
Should the heater outlet setting exceed the BOIL OUT
MAX setting, the stage contacts are opened to shut off
the heater. The heater remains off for the minimum off
time and the heater outlet temperature falls 2º F (1º C)
below the BOIL OUT MAX setting.
NOTE: BOILER OUT MAX is set using DIP Switch
"A": OFF = 235°F, ON = 200°F (see Fig. 23).
Heater Firing %
0
- - - (OFF)
2
Ignition & Min Fire
4
33%
6
42%
8
50%
10
58%
12
67%
14
75%
16
83%
18
91%
20
100%
INSTALLATION
The following describes field installation:
For field installation, this controller is shipped inside a
water-resistant enclosure (see Fig. 19).
includes an alarm relay and two terminal blocks
(labeled P1 and P2) with built-in decals describing the
various connections. See Fig. 23 for proper wiring.
CAUTION: The 24VAC connection must be applied
to Terminal Block P3 (pins 1 and 2).
Electrical Connections to the
Controller
The installer should test to confirm that no voltage is
present at any of the wires during installation.
Powered Input Connections
Pump Contact
The Pump terminals (pins 17 and 18 on P2) are an iso-
lated output in the controller. There is no power
available on these terminals from the controller. This
output is to be used as a switch to either make or
break power to the pump. Since this is an isolated con-
tact, it may switch voltage up to 120 VAC that does not
to exceed 5 amps. For larger pumps, a contactor must
be used.
Heater Contacts
The Stg terminals (11 and 12) are isolated outputs in
the Controller. There is no power available on these
terminals from the Controller. These terminals are to
be used as a switch to either make or break the heater
circuit. When the Controller requires the heater to fire,
it closes the contact between these terminals.
Alarm Contact
For field installations, terminals 19 and 20 provide dry
contacts for an alarm. The alarm contacts only pro-
vide notification of a controller fault.
13
This kit
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