Loosing Pressure

[SPrater1270]

I have a 1.5 HP pump for a sand filter. It looses pressure after filtering for awhile. If I backwash then go back to filtering, the pressure goes back up - for a while. We changed the sand (it was 5 yr old) and it seemed to help - for a while. Now, it loses pressure again. We dried everything off and watched for leaks, but could not find any. However, I do see air bubbles in the little tub when filtering. (Sorry, I do not know all the technical terms.)

 

[duraleigh]

If the "little tub" is the front part of the pump, then it sounds like you have a suction side air leak.

That means that somewhere between your pump and the skimmer, air is being sucked into your system. Starting with the skimmer and making sure it's not gulping air, you need to work your way back to the pump and check all the joints, etc for a place where the air is getting in.

 

[SPrater1270]

Hmmm - there is only one tube from the skimmer to the tub, so could it have a pin-hole or something? And, the skimmer itself seems to be working normally.

 

[duraleigh]

Just to make sure, we're on the same page is the "tub" the front of the pump?

 

[SPrater1270]

Yes - from the skimmer there is a tube to the tub which is connected to the front of the pump. From there a tube goes into the multiport.

 

[duraleigh]

Check all the connections. Especially check to see that the 0-ring is seated correctly on top of the "tub". Air is leaking somewhere along that path I described above.

 

[SPrater1270]

I think this is like when you take your car in for repair and it stops doing whatever it was doing! It has not lost pressure all morning.... I guess it just had to 'recover' from changing the sand. I don't know if that's even possible, but I hope it lasts. I'm still going to check all that you said to, though. Thanks!