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Status Code 25
MODEL SELECTION OR SETUP ERROR – If status code 25 only flashes 4 times on power-up the variable speed furnace
control is missing its model plug (PL4) and is defaulting to the model selection stored in memory.
If status code 25 flashes continuously it could indicate any of the following:
1. Model plug (PL4) is missing and there is no valid model stored in permanent memory. This will happen if you forget to
install the model plug (PL4) on a service replacement board.
2. Thermostat call with SW1-1 ON.
3. Thermostat call with SW1-6 ON.
4. SW1-1 and SW1-6 both ON together.
5. Two different furnace models twinned.
6. Board does not recognize 355BAV model plugs HK70EZ057 – 061. Furnace board date code 4106 or later required.
STEP ACTION YES
NO
GO
TO
1.
Turn power off, remove the blower access panel, and disconnect User Interface ABCD
connector (if used) or the R thermostat lead (if used) from the furnace control board.
2
2.
Turn power on and depress door switch. Use a piece of tape to hold switch closed.
3
3.
Does status code 25 flash only 4 times on power-up?
4
6
4.
The model plug is missing or invalid but the control will default to the model stored in
memory. The furnace will operate properly as if the model plug was installed. If you have the
APM program you can confirm the setting in memory.
5
5.
Go to page number indicated in Index for CLEANUP AND START-UP INSTRUCTIONS.
INDEX
6.
Is setup switch SW1-1 in the ON position?
7
8
7.
Put setup switch SW1-1 in the OFF position.
5
8.
Is setup switch SW1-6 in the ON position?
9
10
9.
Put setup switch SW1-6 in the OFF position.
5
10.
Is this a new service replacement control?
19
13
11.
You need to remove the model plug PL4 from the old control and install it on the new
replacement control. Once you install the model plug the power to the furnace needs to be
reset because the model plug is only read on power-up.
12
12.
If the model plug is not available from the old control, reference the model plug chart on the
wiring schematic for the correct part number. If absolutely necessary you can install two
resistors into the PL4 connection on the control board. R1 goes across the middle 2 pins and
R2 goes across the outer 2 pins. Reference the model plug chart on the schematic for the
correct resistance values. Resistors can be purchased at a nearby Radio Shack. The resistors
need to be within 10% of the stated value. Check with an ohm meter before installing.
5
13.
Is this furnace twinned with another furnace?
14
17
14.
Is the MAIN furnace flashing the status code?
15
17
15.
Do the furnaces have the same model number on the rating plate?
18
16
16.
Replace one of the furnaces because you cannot twin different size furnaces.
5
17.
Replace the variable speed furnace control.
5
18.
One of the model plugs is bad. Ohm out each one and replace the one that does not match the
model plug chart on the wiring schematic.
5
19.
Is the model plug PL4 from the old control installed?
20
11
20.
On 355BAV furnaces make sure you have installed a furnace control date code 4106 or later.
The date code is the last 4 digits printed after the board part number in the WHITE box near
the L2 terminals on the right side of the furnace control. Reference Figure 1 in Appendix A for
the location of the board date code.
5
Status Code 31
HIGH-HEAT PRESSURE SWITCH OR RELAY DID NOT CLOSE OR REOPENED - This status code can occur under the
scenarios shown below. Keep in mind that whenever the variable speed furnace control shuts unit down, gas remains off or
shuts off immediately, inducer continues running for 15 seconds, and if the blower is running, it remains running at low heat
airflow or reduces to low heat airflow for the selected off-delay. A miswired gas valve can cause this problem so make sure the
BLUE wire goes to the gas valve M terminal and the GREEN/YELLOW wire goes to the gas valve C terminal
.
- LOW HEAT
1. PREPURGE OR STEADY-STATE - If the high heat pressure switch input turns ON the variable speed begins flashing status code 31 and
transitions to high heat. After the call for heat is satisfied and the blower off-delay is completed the control will stop displaying status code
31.
