Install Instructions

18
9. CHECK FOR GAS AND WATER LEAKS
GAS LEAKS may result in re or
explosion.
WATER LEAKS may cause extensive
property damage.
Refer to Appendix E – Filling the System and
Checking for Leaks
8. PROGRAM THE CONTROLS (continued)
Zone (tt2)
When there is no IWH the “DHW
Circulator” output may be congured to
control a second heating zone. This is
particularly helpful when the home uses
only two heating zones. The control
replaces the need for a two circulator
zone panel. When DHW Terminal
Function (dh_) is set to “tt2" the control’s
two circulator outputs are used to control
two independent heating zones. Refer
to Table 8c. A “TT” input causes a call
for heat and energizes the “System
Circulator” output to service heating zone
1 and a second zone's thermostat wired
to the “DHW” input causes a call for heat
and energizes heating zone 2 circulator
wired to the "DHW Circulator" output.
When there is a Second Heating Zone
(call for heat) the boiler is started and the
DHW Circulator terminal is energized.
When Second Heating Zone is de-
energized the call for heat is ended and
the Second Heating Zone Circulator is
de-energized. A Second Heating Zone
is detected by sensing a voltage on the
"DHW" terminal.
Using the IQ Option Panel
Table 8c: DHW Terminal Function (dh_)
Selection = Second Heating Zone,
(Parameter dh_ = tt2)
Call for Heat Circulator Status
T-T
Input
DHW
Input
System
Circulator
Output
(Zone 1)
DHW
Circulator
Output
(Zone 2)
off off off off
on off on off
on on on on
off on off on
IQ Option Cards are available from U.S. Boiler
Company distributors and are the simplest way
to add functionality, safety and efciency to your
heating system. The IQ Option Panel provides
an easy and convenient means to "plug-in" an
Auxiliary High Limit, Low Water Cut-off and/or
Outdoor Reset function.
For installation, programming, and troubleshooting
instructions, refer to the instructions supplied with
those cards.
Using the Optional LCD Display Kit
The LCD Display is an easy to use touch screen
type display that allows a technician to monitor and
adjust the control and connected IQ Option Cards.
All boiler settings, status and error codes are
displayed in full text. All Outdoor Reset IQ Option
Card parameters are adjustable with graphic and
help information screens. The LCD Display Kit
includes a mounting bracket and wiring harness
to allow mounting in the ESC plastic hood above
the front door. For installation, programming,
and troubleshooting instructions, refer to the
instructions supplied with the display.