Water, Wastewater & Pump Systems Manufacturing worked example

Seal Failure Warranty Reserve at 5.76% expected seal failure rate over warranty term: a worked example

Suppose expected seal failure rate over warranty term falls to 5.76%. This page works the full calculation at that level so you can see exactly which result moves and by how much. Estimate seal failure warranty reserve for water and wastewater pumps from installed population, replacement cost, expected failure rate, and fixed handling cost.

The inputs for this scenario

  • Pumps under seal warranty: 300 pumps (held at the documented default)
  • Mechanical seal replacement cost per pump: 650 $ / pump (held at the documented default)
  • Expected seal failure rate over warranty term: 5.76 % (the input this scenario stresses; the baseline uses 8)
  • Fixed claim administration cost: 5,000 $ (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Total seal warranty reserve = pumps under seal warranty x seal replacement cost per pump x expected seal failure rate + fixed claim handling cost.
  • Total seal failure warranty reserve cost works out to 16,232 $ at these inputs, and this is the headline figure for the scenario.
  • Seal failure warranty reserve cost per unit works out to 54.11 $ / piece at these inputs.
  • Variable seal failure warranty reserve cost works out to 11,232 $ at these inputs.
  • Fixed seal failure warranty reserve adder works out to 5,000 $ at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where expected seal failure rate over warranty term sits at 8% and the headline result is 20,600 $, this scenario comes in 21.2% below the baseline at 16,232 $.
  • It computes the total warranty reserve and per-pump reserve for expected mechanical seal failures across a pump fleet. When the numbers land here, the stressed input is the lever to work; the walkthrough above shows exactly how much each output recovers as it climbs back toward the baseline.

Results at a glance

  • Total seal failure warranty reserve cost: 16,232 $ (headline result)
  • Seal failure warranty reserve cost per unit: 54.11 $ / piece
  • Variable seal failure warranty reserve cost: 11,232 $
  • Fixed seal failure warranty reserve adder: 5,000 $

Run it with your numbers

  • To rerun this with your own numbers, open the live Seal Failure Warranty Reserve calculator, set expected seal failure rate over warranty term to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.