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EI203
drive) furnace, see next section.
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Depending upon furnace manufacturer, the common may have various letter terminology –
C, B, X. “C” is 24-volt common for this product.
d.
Utility load control – extend the two blue wires to an appropriate set of wires or contact closure
within the power company control receiver. For electric energy operation (off-peak) the two blue
wires represent a contact closure as shipped.
Do not apply external voltage or external power to
the blue wires, they are simply looking for a closed contact during off-peak.
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Optional – where load management interrupt does not apply simply leave the two blue
wires tied together and wire nutted.
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If load control reverse logic is required, call factory.
4.
BLOWER CONTROL – this is handled within the 4 (or 5) wire connection between the DHC control board
bottom and the gas furnace hookup. The HeatChoice DHC control board allows the blower to turn off and
operate under the control of the gas furnace during standby or utility interrupt. During cooling the DHC
logic keeps the blower running during utility air conditioning interrupt to circulate summer air.
a.
Delay on/off – within the DHC logic, the blower turns on with an approximately 10 second
delay. At the end of the thermostat heat cycle, the blower must continue to operate for at least
30 seconds to cool off the HeatChoice metal rod electric elements.
b.
Purge cycles – effective version 2-03-05, there is a 1-minute delay before allowing a gas
furnace W input in order to allow the furnace blower to cool off the HeatChoice elements. Also
there is a built-in delay before turning on the electric elements after the gas furnace has been on.
c.
Thermostat “G” function – do not connect the thermostat G wire directly to the gas furnace G
screw. The thermostat G wire must pass through the HeatChoice DHC module from top point
to the bottom point.
5.
DOWNFLOW OR HORIZONTAL ONLY - HI-LIMIT PROBE EM5714 (shipped loose in control box
cabinet) – Install probe as close as possible below Electro-Mate on the right side, see drawing EA104.
Within the upper right portion of the main control box locate one of the two wire nuts that join a red wire
from the right hi-limit probe to a red/white wire from the DFC wire harness, see drawing ES201. Remove
wire nut, route, and connect in series to this additional hi-limit probe’s red wires.
POWER ON, STARTUP
1.
Use the airflow verification procedure within the attached warranty certification form. If you experience hi-
limit cycling or plenum temperatures greater than specified, this must be corrected before leaving the site.
Correction can include verification of proper placement within the plenum, plenum deflectors/baffles
(previous diagrams), increasing overall furnace airflow capacity, enlarging furnace blower,
or
disconnecting
lower elements to reduce the heating capacity. To disconnect elements, simply remove (starting with lower
left element) the element wire going to the hi-limit. Tape off and protect both the element end and the
removed wire.
2.
Using general heating and utility load control experience, cycle the HeatChoice with the roomstat and load
control receiver functions.
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The blower must come on within 30 seconds and the blower will continue approximately 1 minute
after termination of the heat cycle. The blower function from the HeatChoice will also terminate
during load control. It is expected the gas furnace will do its own blower control during standby.
3.
Check blower current, compare to nameplate reading and verify blower motor is not being overloaded.
4.
Complete the warranty certification form and return to Electro Industries, address or fax shown.
5.
Recheck all electrical connections and screws for tightness, including factory wiring.
