Pentair SMBW 4000 Series

Questions and Answers:

I
iduncanJul 27, 2025
Why is the pressure reading high on my Pentair Swimming Pool Filter gauge?
- D
  dominguezamyJul 27, 2025
  A high pressure reading on your Pentair Swimming Pool Filter gauge can be due to several reasons. There might be a restriction on the discharge side, so locate and correct any obstructions. Calcium deposits on the filter elements could be the cause; if so, remove and acid wash the elements. The pump horsepower may exceed the filter flow rate; establish the pump flow rate and compare it with the maximum filter flow rate requirement. If your system includes a heater, the flow valve on the heater may be stuck open, requiring adjustment or replacement. Lastly, the filter gauge itself may not be working properly, so inspect, repair, or replace it as needed.
S
Stacey CampbellAug 2, 2025
How to fix a leak at the lid of my Pentair SMBW 4000 Swimming Pool Filter?
- K
  kwashingtonAug 3, 2025
  A leak at the lid of your Pentair Swimming Pool Filter can stem from several issues. A damaged o-ring is a common cause, so replace it. The o-ring could also be contaminated; in this case, clean the o-ring and the inner lip of the lid and retainer band at the top of the tank. If the clamping band is too loose, tighten it. Finally, inspect for any cracks in the lid or tank body, and replace the cracked part if necessary.
A
Anna MunozAug 11, 2025
What to do if diatomaceous earth (D.E.) is going back to the pool from my Pentair Swimming Pool Filter?
- W
  washingtonrobertAug 11, 2025
  If diatomaceous earth is going back to your pool from your Pentair Swimming Pool Filter, it could be due to several reasons. Ensure internal parts are assembled correctly. A damaged manifold may be the cause, so replace it. Check for torn element fabric and repair or replace the element. Check for air leaks and repair as necessary. Air leaks can cause the system to drain down allowing D.E. back to the pool. Also, a missing vent cap can cause this issue, so replace the cap.
K
Kimberly EatonAug 17, 2025
Why does my Pentair Swimming Pool Filter have a short filter cycle?
- S
  Sandra PittsAug 18, 2025
  A short filter cycle in your Pentair Swimming Pool Filter could be due to a poor backwash procedure, so ensure you are using the correct backwash procedure. It could also be caused by using too little or too much D.E.; backwash and add the correct amount of D.E.

Pentair SMBW 4000 Series Specifications

General

Type	Sand Filter
Working Pressure	50 psi
Air Relief Valve	Yes
Tank Material	Fiberglass
Drain Connection	1.5 inches
Inlet/Outlet Connection	2 inches
Media Required	Sand
Pipe Size	2 inches