Electro Industries EM-WE1025H Installation Manual page 30

- HP – interrupts only the outdoor compressor unit, electric energy continues without
an OT temperature shut down reference
Note: "0" position does not disable outdoor sensor. This only disables the built-in heat
pump ODT function. With the dial switch "0" position the heat pump becomes a direct
function of the room thermostat and/or standby mode.
Standby (SB) – the WarmFlo control system has transferred the thermostat or heat active
function to the standby furnace via the appropriate Furnace Interface module (WF-EZ3, etc.).
These actions cause SB.
- SOT-S timeout – thermostat continuous run time.
- MU timeout.
- ODT dial switch value – EL to SB mode.
- A1 tab at 24 volts – any switching device which raises A1 tab to 24VAC.
In addition the Furnace Interface module (EZ3, EM3, etc.) sends a signal via J2-4 (blue, high DC)
- Load Control interrupt (open blues)
- Front panel switch
- Added remote switch, "SB" tab to common
Note: Electro-Helps V has additional troubleshooting conditions that will help evaluate
standby.
SB (Gas) 5-Minute Safety – when in the standby mode (see previous section) there is a 5-minute
timer which begins at each heat call. If after the 5 minutes the ST sensor is less than 80°, the
logic board itself goes into an automatic reset and restart. This simply means it attempts to begin
the heat cycle using electric in case the furnace did not ignite or "out of gas". However, if it is in
the SB mode because of Load Control it will still remain SB and try the gas furnace again. The
system will never go back to electric if Load Control is set for on-peak or A1 tab high.
- Typically this is disabled for boiler control applications.
- Analyzer or PC software can disable this function.
- As an added non-freeze safety feature, the program counts these 5-minute resets. If
the count reaches 40 (200 minutes) and each time the ST is still less than 80°, the
system will revert back to electric to bring up the temperature of the building, one
thermostat cycle only.
Delay, transfer from electric to standby – because there are a multitude of gas furnaces which
turn off the blower during their internal heat exchanger warm-up, there is a 1-minute delay before
the gas furnace receives the W input. During this 1-minute the gas furnace G function remains
high allowing the blower to purge out the heat on the Electro-Mate elements. After the 1-minute
the G function drops and the gas furnace W function goes high.
Delay, transfer from standby to electric – if the unit was operating in SB for more than 1
minute, the follow-up transfer back to electric engages a 2-minute delay before the HP
compressor relay is activated and any of the electric stages are activated. The blower will react to
the call for heat, but the elements will stay off for 2 minutes in order for the blower to cool down
the furnace heat exchanger. In addition the WarmFlo logic stages up from stage 1 through the
various temperature/delay staging sequences.
Blower operation – the air handler or fossil fuel furnace blower is operated from its own fan
center (G screw). The activation of this "G" input is either directly from a heat pump (total
electric system) roomstat "G" screw or in the case of dual heat from the Furnace Interface module
(WF-EZ3, LGR4, EM3, etc.). The Interface module and its wiring or association with the room
thermostat completely controls the blower. There is nothing on or within the WarmFlo control
board itself which has anything to do with the blower function.
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