stenner check valve keeps going bad

march2012

LifeTime Supporter
Jan 21, 2012
472
TX
I have had the pump for 3 years and this is the second check valve to go bad. When it happens my bleach tank slowly fills up with pool water.

I saw references to the fact that the pump should prevent backflow and it probably does, but a little still probably backflows.

I saw references to cleaning the check valve, but couldnt find the instructions

How often are people's check valves failing and if they are failing this often, does anyone have a better source?
 

mikespoolfl

LifeTime Supporter
Mar 4, 2011
179
Florida
On the 45mhp10 the max pressure is 100 psi. That's a lot to over come to have back flow because it has to make it by 2 rollers and the duckbill also. How long has it been since you replaced the tube.
 

march2012

LifeTime Supporter
Jan 21, 2012
472
TX
On the 45mhp10 the max pressure is 100 psi. That's a lot to over come to have back flow because it has to make it by 2 rollers and the duckbill also. How long has it been since you replaced the tube.

Replaced the tubing about a year ago. Looks like the check valve isnt bad though. Poked around at the membrane with some pliers (there was some sediment caked in there) I took off the tubing and turned the pool filter pump on and no water came backwards through the check valve.

I had the stenner pump set to run all afternoon and it took a few gallons out of the tank this afternoon (mostly very dilute chlorine) so it might be ok.

Ill check the tubing on the stenner pump

If the check valve is good, but the tubing is going bad, how would pool water get into the bleach tank?
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
24,208
SouthWest Alabama
There's almost no way that pool water can flow backwards. It would have to flow back through the check valve and the pinch rollers before it would ever get to the tank. If the pump is working there's no way liquid can back up through the pump.

There are two ways for the pump tube to fail. One is to break or split, and the other is for the tube to lose it's elasticity and go flat. If it breaks, either the pump won't prime or it will leak fluid out of it. Depending on where the break is. If the tube goes flat, the pump won't pump anything.

If you're getting water in the drum I'd look at it being rain, etc..
 

march2012

LifeTime Supporter
Jan 21, 2012
472
TX
its definitely not rain and the pump is definitely pumping. I set it to run for 24 hours and it cleared the tank (I ended up doing this twice).

Filled the tank with bleach again it drained it about 1/4 and now is full again.

This is driving me nuts. I dont know where to start.
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
24,208
SouthWest Alabama
The rollers press against the tube using spring pressure. The only way for water to flow backward through the pump and into the tank is if one or more of the rollers lost it spring tension and is not pressing on the tube hard enough. Pull the pump out and remove the bottom cover and see if that's the case.

Also I missed answering about the duckbill (Check Valve). If you take the check valve housing apart in the middle you'll be able to see the duckbill. It's just a rubber piece with a tiny split in it and calcium buildup or a tiny bit of trash will cause it to leak. You can buy just the duckbill.
 

jamcha02

Well-known member
Jul 10, 2013
307
My check valves were failing every 3 months with acid injection. I just removed the check valve and inject directly into the duckbill. No issues with backflow and all is well
 

march2012

LifeTime Supporter
Jan 21, 2012
472
TX
I bet that's it I haven't oiled the mechanism either would surprise me if it is stiff

Sent from my SAMSUNG-SGH-I747
 

march2012

LifeTime Supporter
Jan 21, 2012
472
TX
Ok I think I found the problem. I bought new tubes, when I went to replace the tube I noticed that the old tube was a full inch longer than the new ones. At first I thought I bought the wrong tubes, but apparently they stretch and thus get narrower so they are not sealed all the way. They would still pump bleach when it was on, but when off they werent sealed. It still makes me wonder about the check valve, but ill see if this works.

The pool is 3 years old, but Im pretty sure I replaced the tubes once. Possibly not though :)
 
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