Brand:Frigidaire
Model Number:FDPH431LAF OA,
Main Symptom:no water
What happens & when:
Seems to do entire cycle but no water enters. Bench tested water valve and float valve—both OK. Put back in and it worked for fine twice (three days apart) then same problem. Could a high-heat switch might cause this? Or no voltage to switch? Problem with board?
For your Frigidaire FDPH431LAF0A, I would not suspect a high-limit/high-heat switch for a no-fill problem. The high-limit thermostat is mainly part of the heating circuit and normally will not prevent the dishwasher from filling.
Since you bench-tested the water inlet valve and float switch, reinstalled them, and the dishwasher worked twice before failing again, this sounds more like an intermittent electrical/control problem than a bad valve.
1. Start a Normal cycle and listen carefully.
The dishwasher should usually run the drain pump briefly at the beginning and then attempt to fill.
When it reaches the point where it should be filling:
This is the most useful test.
LIVE POWER WARNING: This measurement is made with the dishwasher powered and running. Keep your meter probes and hands away from the chassis and other terminals.
Set the meter to AC volts, preferably the 200/600 VAC range.
Leave the valve connected and carefully back-probe the two valve wires.
Start a cycle and watch the meter when the machine should fill.
You should see approximately:
120 VAC across the two inlet-valve wires during fill.
| Reading during attempted fill | What it means |
|---|---|
| ~120 VAC but no water | Valve isn’t opening under actual conditions, restricted supply, plugged valve screen, or plumbing problem |
| 0 VAC | Control isn’t energizing valve — continue below |
| Voltage appears briefly then disappears | Control is terminating fill because of another input/sensing issue |
Even though it bench-tested correctly, don’t rule it out yet.
The important question is whether the switch and its wiring are actually completing the circuit when installed.
Unplug the dishwasher.
Operate the float by hand while checking the switch with the meter on continuity/Ω.
With the float in the normal down/no-overfill position, you should have continuity through the appropriate fill-enable contacts. Raising the float should change the switch state.
Also wiggle the wiring harness while measuring it. An intermittent connector or broken wire can easily explain:
Worked twice after I disturbed/reinstalled everything, then quit again.
That detail makes me particularly suspicious of a connection or harness issue.
I would inspect this as well, although it’s somewhat less likely if the dishwasher proceeds normally through the rest of the cycle.
Look for:
If there’s 0 VAC at the valve during the fill portion, unplug the dishwasher and inspect the harness between:
Control → float/overfill circuit → inlet valve
Pay special attention to connectors you disturbed when you removed the valve and float components.
Look for a terminal that has backed partially out of a connector. Sometimes it looks connected but loses contact once everything is pushed back into position.
Based on what you’ve already done, my order of suspicion would be:
1. Intermittent wiring/connector at the valve or float circuit
2. Float/overfill switch intermittently opening when installed
3. Main control not supplying the fill circuit
4. Inlet valve intermittently failing under actual water pressure
5. Water supply/restriction
I wouldn’t replace the control board yet.
The deciding test is very simple: measure AC voltage directly across the inlet valve while the dishwasher is supposed to be filling.
If you get 120 VAC and no water, stay on the valve/water-supply side.
If you get 0 VAC, then we work backward through the float circuit and wiring to determine whether the board isn’t sending power or something between the board and valve is interrupting it.