Why is the Check Water light blinking on my Scotsman CU50 ice machine?

Short answer: No water sensed within fill time. If your Scotsman CU50 undercounter cuber is showing Check Water light blinking, the controller has logged a specific, documented condition. This page covers what it means, what causes it, what you can safely fix yourself, and when — and why — it takes a technician.

What exactly is the machine telling you?

If the water sensor cannot detect water after the inlet valve has been open for the maximum fill time (2.5 minutes), the controller stops and blinks the Check Water light, then retries the fill every 20 minutes.

Which machines show this?

the Scotsman CU50, a compact undercounter gourmet-cube machine common in bars, coffee shops, offices and break rooms. There's no code display on this one — it reports through a small set of indicator lights on the control panel, chiefly Check Water and Time To Clean, alongside the On/Off and Clean-Reset buttons. Because it lives under a counter, the usual suspects are the ones you can't see: a kinked line or a partly closed valve behind the cabinet, and scale from an overdue cleaning. The machine is patient by design — a failed water fill retries every 20 minutes on its own — so give it time after you fix the supply rather than power-cycling it repeatedly.

What causes it?

• The water shut-off valve to the unit not fully open
• Building water off, or a kinked line to the machine
• An overdue water filter, where one is installed
• A failing inlet solenoid valve or scaled water sensor probes — the technician-level causes

Can you fix it yourself?

Usually, yes. The controller couldn't sense water within the 2.5-minute fill window. Open the valve, check the line, swap an overdue filter — then just wait, because the unit retries the fill on its own every 20 minutes.

Step by step — what to try, in order:

1. Open the water shut-off valve to the unit fully
2. Confirm building water supply is on and the line to the machine isn't kinked
3. Replace the water filter if one is installed and overdue
4. Let the machine retry — it attempts a refill automatically every 20 minutes

When do you need a technician — and why?

If water is reaching the unit and the light keeps blinking, the inlet solenoid valve or the water sensor probes are at fault. Testing a solenoid and cleaning or replacing sensor probes means opening the unit and working at the control circuit — a technician's job on an undercounter machine.

If it does come to a service call and you're in Nashville, TN or Birmingham, AL, we maintain independently compiled lists of local companies that service commercial ice machines — real businesses with verified contact information, none of whom paid to be listed.

Related questions

What does Check Water light blinking mean on a Scotsman CU50 undercounter cuber?

No water sensed within fill time. If the water sensor cannot detect water after the inlet valve has been open for the maximum fill time (2.5 minutes), the controller stops and blinks the Check Water light, then retries the fill every 20 minutes.

Can I fix Check Water light blinking on a Scotsman CU50 undercounter cuber myself?

Usually, yes. The controller couldn't sense water within the 2.5-minute fill window. Open the valve, check the line, swap an overdue filter — then just wait, because the unit retries the fill on its own every 20 minutes.

When does Check Water light blinking on a Scotsman CU50 undercounter cuber need a technician?

If water is reaching the unit and the light keeps blinking, the inlet solenoid valve or the water sensor probes are at fault. Testing a solenoid and cleaning or replacing sensor probes means opening the unit and working at the control circuit — a technician's job on an undercounter machine. If water is reaching the unit but the light keeps blinking, call a technician to check the inlet solenoid valve and water sensor probes.

Source: cu50_service_man.pdf (scotsman-ice.com)