Large Dome Lid Knob X9110

The Large Dome Lid Knob (part# X9110) is a genuine Tacony OEM replacement part from the recovery and solution tank assembly of the Tornado Marathon SE 900 self-contained carpet extractor. It is the hand knob that clamps the large recovery dome lid down onto its gasket.

What the Large Dome Lid Knob does

The Large Dome Lid Knob provides the clamping force that holds the big recovery dome against its gasket. That seal is what lets the machine hold vacuum. Without adequate clamp pressure the dome leaks air, and the machine loses lift at the wand even though the vacuum motor is running perfectly.

When to replace the Large Dome Lid Knob (X9110)

Replace it when the knob is cracked, when the thread has stripped so it spins without drawing down, or when the moulding has softened and flexes under hand pressure. The classic symptom is poor water pick-up that improves if you press down on the dome by hand while someone runs the wand.

Large Dome Lid X9110 — fitment and installation notes

Do not over-torque it: the knob is a hand-tight fitting and cranking it hard is what strips the thread and crushes the gasket. If you need extra force to hold vacuum, the gasket is the part at fault, not the knob. Tacony builds the Tornado Marathon SE 900 and the Powr-Flite Prowler PFX900S on a single machine platform, so this component carries across both brands rather than belonging to either one. It is a shared Tacony component and may fit additional models beyond those listed — call us and we will confirm against your serial number.

Compatible Models for the Large Dome Lid Knob

• Tornado Marathon SE 900 — Model 98170
• Powr-Flite Prowler PFX900S
• Powr-Flite PFX900SG

Twin City Vacuum has been selling and servicing commercial floor-care equipment since 1956 from 5415 West Broadway, Crystal, MN 55428. We stock genuine Tacony parts and ship nationwide. Browse the full Tornado 98170 parts catalogue, or see the manufacturer at tornadovac.com.

Frequently Asked Questions

What does the Large Dome Lid Knob do on the Tornado Marathon SE 900?

The Large Dome Lid Knob provides the clamping force that holds the big recovery dome against its gasket. That seal is what lets the machine hold vacuum. Without adequate clamp pressure the dome leaks air, and the machine loses lift at the wand even though the vacuum motor is running perfectly.

How do I know if my Large Dome Lid Knob needs replacing?

Replace it when the knob is cracked, when the thread has stripped so it spins without drawing down, or when the moulding has softened and flexes under hand pressure. The classic symptom is poor water pick-up that improves if you press down on the dome by hand while someone runs the wand.

What models is the Large Dome Lid Knob (part# X9110) compatible with?

The Tornado Marathon SE 900 (Model 98170), the Powr-Flite Prowler PFX900S and the PFX900SG. It is a shared Tacony part and may fit further models; call us to confirm.

How do I order the Large Dome Lid Knob (part# X9110) or get help?

You can add the Large Dome Lid Knob (part# X9110) directly to your cart on this page, or call us at 763-535-0770. Our staff at 5415 West Broadway, Crystal, MN 55428 has been servicing Tornado equipment since 1956 and can help confirm the right part for your machine.