The short answer
This page covers the BlueStar BS-series dishwasher, the models whose number carries the BS prefix. A BlueStar dishwasher left standing with water in the bottom is nearly always blocked somewhere it can be reached. On a North American pro-style installation the countertop air gap is the part that blocks most often and the part nobody thinks of, followed by the filter in the tub and the disposer connection under the sink.
What you observe on these models
- Standing water above the filter at the end of the cycle — The tub did not empty. A film in the sump is normal; water over the filter is not. On the BS models this is the observation to trust first: it can be made from the front of the appliance without moving anything.
- Water spitting from the air gap fitting on the countertop — A blocked air gap, and a definitive one: it is the only symptom on this list that points at a single part.
- The pump runs but nothing leaves — A closed path somewhere between the sump and the sink: filter, hose or air gap.
- NEAR MISS - a thin film of water in the sump alone — Deliberate, and there to keep the seals wet.
Causes, most likely first on this family
- A blocked filter and sump — First. Everything the wash removes collects here, and a filter that has not been cleaned closes the path the pump needs.
- A blocked countertop air gap — Second on this kind of installation. It is a small chamber that collects food debris, it is outside the machine where nobody cleans it, and it stops the drain completely when it fills.
- The disposer connection, including a knockout plug never removed — Third, and the classic fault on a newly installed machine: the drain hose is connected to an inlet that was never opened.
- A kinked drain hose or a lost high loop — Fourth. Behind a built-in machine the hose is easily crushed when the unit is pushed back into its opening.
- The drain pump jammed or failed — Last. Glass and fruit stones do jam impellers, but the four causes above account for most standing-water calls and all of them are reachable.
- Where this ranking departs from the brand-generic page — The cause that moves is a blocked filter and sump: it leads here because the filter on these models is removed from inside the tub without tools, so the check you can complete while the machine stays where it is comes first.
Check in this order, and why
- Bail out the water, lift the filter and clear the sump — On these models the filter on these models is removed from inside the tub without tools, so the check you can complete while the machine stays where it is comes first, which is why this check leads. Gloves on for glass. This is the second place the path closes and the one inside the machine.
- Lift the cover off the air gap on the countertop and look inside — Debris in that chamber is a complete diagnosis.
- Check the disposer inlet and run the disposer for a moment — On a new installation, confirm the knockout plug was removed; on an old one, clear the inlet.
- Look behind and under for a kinked hose and the high loop — The loop stops the sink siphoning back into the machine; the kink stops the pump pushing anything out.
Before you open anything
Safety
Switch the machine off at its breaker before reaching into the sump - a capacitor can hold a charge after the power is off. Never put a hand into a disposer, and never run one while clearing the dishwasher connection. Assume broken glass in the filter.
When to call a technician
Call when the air gap, the filter, the disposer connection and the hose are all clear and the tub still holds water - at that point it is the pump, the check valve or the control, which means moving the machine with power and water connected. Call a plumber rather than an appliance technician if the sink itself is slow: the machine is only reporting the blockage.
Nearest pages of this class
Lead Appliance Repair Technician · 12 years experience
Experienced technician with 12 years specializing in washing machine and dryer repairs across all major brands.
