Kendall SCD 700 Series

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What This Guide Helps With

This guide provides a structured Clinical Engineering approach when a Kendall SCD 700 Series unit is alarming frequently or unnecessarily.

This may present as:

Repeated “Leak” alarms
Disconnection alarms when tubing appears connected
Pressure fault alarms during normal use
Intermittent alarms that clear and then return
Alarm sounds but sleeves appear to inflate normally

The focus is on logical, external, and easily verifiable causes before assuming an internal pressure sensor, valve, or control board failure.

Step-by-Step Troubleshooting

1. Ensure Patient Safety First

Before manipulating tubing or sleeves:
Confirm therapy can be safely paused.
If the device is actively in use on a patient, coordinate with clinical staff.
Do not troubleshoot aggressively while connected to a patient.
Patient safety comes first.

2. Identify the Exact Alarm Message

Read and document the exact alarm wording.
Determine whether the alarm is constant or intermittent.
Note which side (left/right) is indicated, if applicable.
Precise wording helps determine whether the issue is leak-related, pressure-related, or sensor-related.

3. Check All Tubing Connections

Disconnect and fully reseat all tubing connectors.
Ensure connectors are firmly inserted.
Gently tug to confirm secure seating.
Loose or partially seated connectors are the most common cause of nuisance alarms.

4. Inspect Tubing for Micro-Leaks or Kinks

Inspect the full length of tubing for:
Hairline cracks
Pinholes
Soft spots
Sharp bends or kinks
Compression under bed rails or wheels
Even very small leaks can cause repeated leak or pressure alarms.

5. Inspect Sleeves

Check sleeves for:
Torn seams
Worn or weak Velcro
Uneven wrapping
Incorrect size
Ensure sleeves are wrapped snugly and evenly. Improper application can create inconsistent pressure readings and false alarms.

6. Swap Sleeves and Tubing (Isolation Step)

If available, replace sleeves with a known-good set.
You may also:
Swap left and right sleeves.
Swap tubing sets.
Observe results:
If the alarm follows the sleeve/tubing → Accessory issue.
If the alarm stays on the same port → Possible internal valve or sensor issue.
This step helps isolate accessory versus device failure.

7. Observe Pump and Inflation Behavior

During operation, observe:
Does the pump sound smooth and consistent?
Do sleeves inflate and deflate fully?
When does the alarm trigger (inflation, hold, or deflation)?
Normal pump sound with full inflation often suggests minor leaks or sensor sensitivity rather than major pump failure.

8. Power Cycle the Unit

Turn the unit off.
Wait at least 10 seconds.
Restart therapy.
Temporary software or logic faults can occasionally cause nuisance alarms.

9. Evaluate the Environment

Confirm:
Tubing is not being repeatedly flexed or pulled.
The unit is positioned securely.
No condensation or fluid contamination is present at connectors.
The device is not located where tubing is constantly stressed.
Environmental factors can intermittently break the air seal and trigger alarms.

If Alarms Continue After These Checks

If the unit continues to alarm after completing all external checks, the likely cause is internal and not correctable at the bedside.

Possible internal causes include:

Pressure sensor drift
Valve manifold malfunction
Pump wear
Control board fault

Next Steps

Remove the unit from clinical service.
Clearly label it Out of Service.
Send to Clinical Engineering for bench evaluation.

Knowing when to escalate is proper troubleshooting. Continuing to use a device with persistent unexplained alarms can compromise patient safety and confidence in therapy.

Clinical Use Tip

Always move the patient to a properly functioning SCD unit before extended troubleshooting.

Do not attempt repeated resets or accessory manipulation while therapy is required for DVT prevention. Continuous, reliable compression therapy is critical for patient safety.

Work Order Documentation (CCR Method)

Complaint

What was reported by the clinical staff.

Example:

“Repeated leak alarm despite tubing appearing fully connected.”

Cause

What was observed during troubleshooting.

Example:

“Tubing reseated and sleeves swapped. Alarm persisted on right port. Suspected internal pressure sensor or valve issue.”
“Alarm followed sleeve when swapped. Leak identified at sleeve seam.”

Resolution

What action was taken.