Air in Hayward EC-75 Pool Filter

fthrmulcahy

New member
Aug 1, 2021
3
New York
I am having a very frustrating problem...

I have a Hayward EC-75 filter that is becoming air-bound within minutes of starting the pump. The pump has no priming issues and there are no bubbles in the pump basket. However, there are usually significant bubbles coming out of the return after I bleed the filter. Then the bubbles stop and everything but within an hour the filter is airbound and I have to bleed significant air from the filter to get the water flowing again. Then in an hour it's repeat again. I have a Hayward in-line chlorinator next to the filter (not sure if this matters). I've checked the o-rings and seals around everything and I am at a loss where the leak is coming from...thanks in advance for any responses.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
Welcome to TFP :)

Do you have a VS pump? Sometimes running low rpm will not fill the filter completely with water and there will be air in them..

Does the water stop flowing to the pool after the hour?

What is the reason you keep bleeding the air out?
 

fthrmulcahy

New member
Aug 1, 2021
3
New York
Thanks for the welcome! I have a VS pump. It am only running it at high speed. When I start it the pump will prime without a problem and there’s no air in the pump basket. After about an hour the return to the pool is slowing to a crawl. I turn off the pump and open the air bleeder valve on the filter and air is hissing out. Then I start the pump again with the air valve open until water is shooting out and it’ll go for another hour.

Air seems to be building quickly in the filter from the moment I start the pump. If I stop the pump even after a couple of minutes and open the air valve there’s significant air coming out. I just have no clue where it’s coming from since there’s no sign of an air leak from the suction side.
 

Mike1162

Silver Supporter
Jun 13, 2015
1,078
N Tonawanda, NY
I turn off the pump and open the air bleeder valve on the filter and air is hissing out.
Not sure why you're opening the air bleed valve while the pump is off. Is this an inground or above ground pool? If inground you may be hearing air going into the filter.

When was the last time the filter was disassembled & the fingers/tubes hosed off?
Does bumping help?
What's the filter pressure after the air is out of the filter?
What's the filter pressure after an hour?

Turning off one of these filters allows DE to fall off the fingers and it gets redistributed after restarting. It's similar to bumping. From your description I'm 99% sure the filter just needs a good cleaning & recharging with 7lbs of DE.
 
Last edited:

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
When you turn the pump off and open the air valve you are hearing air go into the filter not coming out... Air will only come out when the pump is running...

The reason your water slows down is because your filter is clogged and doing its job.. DE filters collect the most debris.. Is the pool green or have algae? That would explain why your filter is getting clogged within an hour..
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
You are all over it, did not think about that :)

The only way air could get in the filter would be through the pump basket.. they said there was no air in the basket so it can not be that.... the pressure in that filter has to be high after the hour..

What is your PSI on the filter right when it starts up and after the hour?
 

fthrmulcahy

New member
Aug 1, 2021
3
New York
The pressure in the filter is about 10 after startup and 20 after the hour. I went away on vacation a couple of weeks ago and came back to an algae bloom for the first time...seem to have solved it but I didn't take apart and clean the filter afterwards.(I usually do that at the end of the year.) I had tried backwashing a couple of times but the pressure keeps coming back up within an hour after the backwash. I was opening the bleeder valve because I couldn't get the bump handle to move when the pressure was up. Like an idiot I was assuming air was coming out of the filter but cowboycasey was correct and I now see air is going in. So I am going to give the filter a thorough cleaning today. Thank you all for your responses...I've had the pool for years but I still feel like a novice at this.
 

cowboycasey

Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
8,648
Southern OK
Pool Size
15000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool SJ-40
No issue at all, knowing is half the battle... clean that filter and add DE back and you should be good to go... Watch it afterwards as the pressure may still go high... if your clean pressure is 10 psi you should backwash at 13 psi, 20 psi is way above 25% of clean psi.. :)
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
2,987
Spring Valley, NY
Did this few weeks back with EC50 as pressure was building to fast. This agp pool has clean psi of 14 and after backwash and new DE it could last several weeks and move only one psi. Just undid the clamp, pulled it out and hosed off fingers as I watched the greenish color change to almost white. You need to rotate well as it's hard to get to the inside ones. That did the trick and since it's purring along. You gotta do what you gotta do.
 

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