Hello all! I am trouble shooting an issue with my Hayward sand filter. Pool was installed in the fall. Opening from winter went smooth. Typical PSI is 10. All of a sudden filter pressure will drop from 10 to around 7. No clogs in skimmer, good suction from both side ( I close one side with the Jandy Valve and have no issues vacuuming from either side) good flow from the returns. SWG has no air bubbles. Pump basket has a few tiny air bubbles but is filled to the top. I have backwashed with the valve open and with each side turned off. No main drain. When I backwash pressure returns to 10 but slowly drops to 6-7. There are no visible leaks or bubbles anywhere. Water is clean and filtered. I did notice a small amount of sand under the pump basket today when I cleaned it out. I have also checked to make sure the impeller is not clogged. Any other ideas on what could be causing the low pressure??
Low filter pressure troubleshooting.
- Thread starter MFulks24
- Start date
- May 3, 2007
- 18,052
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
First, with a VS pump, most will start at a high RPM during a short priming phase and then step down to a lower RPM which will change the filter PSI. Make sure this is not what you are experiencing.
Also, when filter pressure is lower than normal at the same RPM it is usually due to a restriction on the suction side of the plumbing. Either something stuck in the impeller, pump basket, suction lines, or skimmer.
What is the pump RPM at 10 PSI?
Also, when filter pressure is lower than normal at the same RPM it is usually due to a restriction on the suction side of the plumbing. Either something stuck in the impeller, pump basket, suction lines, or skimmer.
What is the pump RPM at 10 PSI?
Historically 10 PSI it is 3,000. The installer set it up and we haven’t really moved it from initial setup. You are correct when the pump is priming pressure will be around 13. Usually it would drop to 10 and hold steady. Now it drops to 9 and after a few hours it holds steady at 7. No change in RPM we have left it at 3,000.
- May 3, 2007
- 18,052
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
You mentioned that you checked to see if the impeller was clear. Was that done through the pump basket or did you actually disassemble the wet end from the motor to directly inspect the impeller? The later is more definitive.
Also, have you tried back flushing the suction line from the pump toward the skimmer?
Also, have you tried back flushing the suction line from the pump toward the skimmer?
It was done from the pump basket.
I’m not sure I understand. I have backwashed with one skimmer closed and done both sides. How would I backflush the suction line?
I’m not sure I understand. I have backwashed with one skimmer closed and done both sides. How would I backflush the suction line?
- May 3, 2007
- 18,052
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
To back flush the suction line, open the pump basket lid, put a garden hose into the pump basket inlet, wrap a rag around the hose to seal and turn on the water full blast. This should force any debris out to the skimmer.
If that doesn't do anything, then you might consider taking the pump apart to inspect the impeller.
If that doesn't do anything, then you might consider taking the pump apart to inspect the impeller.
- May 3, 2007
- 18,052
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
No, there are no check valves in the plumbing. Backflushing the suction line corrected the issue. Thank you so much for your help!
