I have a Pentair Intellichem system with an acid pump for Ph control. The high level issue is that acid isn’t being delivered to the pool when I dose it. Everything seems to work right up to the check valve where the acid feeds into the return line. When I manually dose it, the pump works. I’ve removed the acid feed line from where it goes into the check valve and acid comes out when I dose it. When I put the feed line back into the check valve, the pump pumps but no acid comes out of the pool end of the check valve. I replaced the check valve with a new one and I get the same behavior. I know it’s possible I got a bad valve but it seems unlikely. Does anyone have any ideas what I can do to troubleshoot it? Thanks!
Pentair Acid Pump Not Dosing
- Thread starter Don E
- Start date
It’s a Pentair pump and it’s about 1 1/2 years old. I actually just replaced the siphon tube on it because it was eaten away. I checked the rollers and they weren’t corroded by the acid at all so I just went with the siphon tube. It gets a good flow of acid and dispenses the right amount when it doses so the pump seems to be working fine. I hate to spend the money for a new head just to see if that’s it. Do you know if the check valve needs high pressure to open? I tried pushing a rod gently into it to get it to move and it didn’t.
Post a picture of the injection pump.
Is it a Stenner pump?
What do you mean by "Siphon" tube? Is it the tube from the vessel to the pump inlet?
Is it a Stenner pump?
What do you mean by "Siphon" tube? Is it the tube from the vessel to the pump inlet?
It’s a Pentair pump. The siphon tube is inside the pump head. It runs on rollers to create suction to send acid to the pool return. They generally need to be replaced every year because they get eaten up by the acid.
tucsontico
LifeTime Supporter
What you're calling the "siphon tube" is actually the "peristaltic tube" or, simply, the "pump tube". The siphon tube runs from inside the tank to the pump. I'll bet the issue is the "duckbill" rubber check valve inside the Stenner black check valve assembly. If you remove the acid feed line from the black check valve assembly and you're getting acid flow when the pump is turned on, the duckbill is deformed/clogged. They should be replaced regularly. I get about 2-3 months out of one. Here's a link to Amazon for that item: Amazon.com : Stenner UCCVDBO Check Valve Duckbill Only, 2/pk : Novelty Lamps : Garden & Outdoor. Keep us posted on your progress.
That's actually a Stenner pump. They make them for Pentair.
The number one reason for the pump not pumping after a pump tube replacement is that the roller assembly doesn't get released completely. It will sound like it does and it will look like it does, but it doesn't.
I would collapse and expand the roller assembly a few times until you're positively sure that it clicks open and is compressing the tube completely.
The number one reason for the pump not pumping after a pump tube replacement is that the roller assembly doesn't get released completely. It will sound like it does and it will look like it does, but it doesn't.
I would collapse and expand the roller assembly a few times until you're positively sure that it clicks open and is compressing the tube completely.
This isn’t a Stenner pump - it’s Pentair. My check valve (in the picture I posted) is all one piece and doesn’t have the “duckbill” piece you referred to. If I understand what you’re recommending correctly, that’s what I’ve done already. I have that in my original post so now I’m trying to figure out where to go from there. If I’m not understanding it, let me know. Thanks.
OK, I’ll give that a try. Would it be pumping acid out the feed line if that were the problem, though?
Yes it can because it's compressing the tube some, it just won't overcome the back pressure at the injection point once you connect the tubing to the check valve.
tucsontico
LifeTime Supporter
OOPS, my bad! Thought that was a Stenner Injection Check Valve assembly. Agree with Bama Rambler. The pump tube may not be getting "squeezed" hard enough.
I found the issue. The pins that the nylon rollers are riding on inside the pump head had backed out about 1/8”, so the rollers were crooked and not putting enough pressure on the tube. Put them back in place and it works fine now. I’ll have to keep an eye on them going forward and replace the pump head if they keep doing it. Thanks to all of you for your help! 
Glad you figured it out. And thanks for coming back and letting us know what it was.
tucsontico
LifeTime Supporter
Thanks for keeping us updated. I'll have a look at my roller assembly today. BTW, I keep a spare roller assembly handy as I've had them corrode so badly they stopped working.
Just a tip. I fill my tank 2/3 acid 1/3 water. It does require re-filling more often but the equipment lasts long due to the diluted acid.