When your Sleep Number bed stops holding air or stops adjusting firmness, the repair usually comes down to one of two parts: the air chamber inside the mattress or the motor pump that inflates it. Both are sold separately as used parts, so the right choice depends on where the problem actually starts.
The Select Comfort Sleep Number 1/2 Air Bed Chamber for King Mattress S-815 E-King is the inflatable bladder that supports one side of a king mattress. The Sleep Number Select Comfort Motor Pump Inflator with Wired Remote, Hose EFCS-1 is the motor that pushes air into that bladder. Pick the wrong one, and you will still be sleeping on a flat or lopsided mattress.
Quick Verdict
If your mattress sags, collapses, or the chamber keeps losing air, replace the chamber. If the bed won't inflate at all, feels hard even at low settings, or the remote doesn't seem to do anything, the pump is the more likely problem. At $75, the pump is the lower-priced option, while the chamber is $124.99.
| Part | Price | What you get | Best for |
|---|---|---|---|
| Select Comfort Sleep Number 1/2 Air Bed Chamber for King Mattress S-815 E-King | USD 124.99 | Used beige single chamber with two air ports and two white caps | Replacing a leaking or sagging side of a king mattress |
| Sleep Number Select Comfort Motor Pump Inflator with Wired Remote, Hose EFCS-1 | USD 75.00 | Used gray motor pump with wired remote and single hose | Restoring inflation and firmness control when the pump fails |
Where Each Product Wins
The chamber wins if the air bladder itself is the weak point. This is the part that holds the air and supports your side of the bed. The seller says the chamber was tested and held air for multiple days with no leaks, which makes it a direct replacement for a chamber that won't hold its shape.
The pump wins if your issue is air movement and control. This is the motor that fills the chamber and adjusts firmness. It is a reasonable first step when you are not ready to replace the larger chamber.
Select Comfort Sleep Number 1/2 Air Bed Chamber for King Mattress S-815 E-King
This used chamber is the side of the bed that does the actual supporting. The seller notes it held air for multiple days with no leaks, so if your current chamber is the reason the mattress sags, this is the part to choose. It comes in beige and includes two white caps for the two air ports. Keep in mind that this is a used item, so expect normal wear such as minor discoloration, marks, and scuffs. Also, this is one chamber for a king mattress, so if both sides need replacing, you would need a second unit. It is the larger, more structural component in this pair.
Sleep Number Select Comfort Motor Pump Inflator with Wired Remote, Hose EFCS-1
This used pump is the motor side of the Sleep Number system. If your mattress stays flat no matter what the remote says, this is the part that gets air moving again. It comes with a wired remote and a single hose. The seller describes it as working well. The main limitation is that it is only the pump: you still need an intact air chamber for the bed to inflate. It is a used component. For troubleshooting a bed that will not inflate, the pump is a practical starting point because it is the component that actually creates the airflow.
Final Choice by Use Case
Choose the chamber when the mattress visibly sags, deflates during the night, or you can hear or suspect air escaping from the bladder. Choose the pump when the bed will not inflate at all, the remote feels unresponsive, or you want to start with the simpler repair. If you are not sure which side is failing, the pump is the safer first purchase because it is the active component that makes the adjustable sleep comfort system respond. If the pump runs and the mattress still does not hold air, the chamber is the part that needs attention.
