Wilbur Curtis G4 Brewer Message: Low Water Flow Warning
Low Water Flow Warning means the inlet valve stayed on longer than the set time during a brew cycle, and this happened twice in one cycle. Check the water supply flow and pressure and the inlet path. It clears on the next brew and returns if the low flow is still there.
Medium: a warning that the brewer keeps running, though the cause can lead to a Water Level Error.
- Code
- Low Water Flow Warning
- Maker
- Wilbur Curtis
- Equipment
- Coffee brewers
- Applies to
- G4 ThermoPro Twin (G4 Gemini family) display message
What does Wilbur Curtis Low Water Flow Warning mean?
During a brew cycle, the control opens the water inlet valve to refill the tank, and it times how long the valve stays on. If the valve is on longer than the set time, the supply is delivering less water than the control expects. When that happens twice in one cycle, the display shows Low Water Flow Warning. The manual calls it a warning, so the brew goes on. It clears on the next brew and returns if the low flow is still present. The troubleshooting guide refers this message to the Water Level Error procedure, so a technician follows those checks. The manual's action is to check the water supply flow and pressure and the inlet path. The thresholds in the manual table did not come through in the text we could read, so we do not quote any numbers. A partly closed supply valve, a clogged line filter or low building pressure are typical sources.
Affected models and control systems
Wilbur Curtis G4 ThermoPro 1.5 gallon brewers, models G4TP2T (twin) and G4TP2S (single). The warning relates to the inlet valve on time during a brew cycle.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Low Water Flow Warning on the display
- Brew continues
- Warning clears on a later brew and returns
- Brew takes longer to refill the tank
Possible causes
Listed in Wilbur Curtis's documentation
- Inlet valve on longer than the set time, twice in one brew
Other likely causes — what usually sits behind Low Water Flow Warning on this control. A technician confirms which one it is before any part is replaced.
- Supply shutoff valve partly closed
- Line filter or inlet screen clogged with scale
- Low building water pressure at busy times
- Inlet tubing kinked
Safe checks before calling for service
- Check that the water supply valve to the brewer is fully open.
- Look at the inlet line for kinks.
- Run another brew and see whether the warning clears.
- If it returns, note the time of day and call us.
How a technician diagnoses Low Water Flow Warning
- Read the display and confirm Low Water Flow Warning.
- Measure supply flow and pressure.
- Inspect the inlet valve, tubing and filter for blockage.
- Follow the Water Level Error checks.
- Replace the failing part.
- Flow and pressure checks need gauges and a flow measurement.
- Inlet valve tests involve line voltage at the control.
- The troubleshooting guide sends this warning to the Water Level Error procedure.
How Low Water Flow Warning differs from similar codes
Low Water Flow Warning is the early warning; Water Level Error is the stop condition.
Technical reference
- Maker documentation
- Wilbur Curtis owner support
- Edition
- F-10023; troubleshooting pages carry 122717A
- Models / control
- G4 ThermoPro Twin (G4 Gemini family) display message
- Section
- ERROR CODES, page EC1
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related Wilbur Curtis coffee brewer error codes
Will the brewer stop?
The manual calls it a warning, so brewing continues.
Why does it come and go?
It clears on the next brew and returns if the low flow is still there.
Is it the same as Water Level Error?
No, but the guide refers it to the same procedure.
Need help with Wilbur Curtis Low Water Flow Warning?
A technician confirms the cause on site and gives you the price in writing before any work starts.