Help! Pool has little to no suction for all pool options(recirculate,backwash,etc)

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
27,155
Laughlin, NV
Sounds to me like there is an issue with the MPV or sand filter. I will let Pat jump back in as I do not have much experience with those.

Thank for doing the test for us.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
So let me say this, the water flows through the sand filter to the salt system but doesn’t have enough flow to keep a prime. So it trickles, is there a way to post a video? So you want me to loosen the Union and let water spray out and see if it keeps a prime that way?
That was the idea Ashley. Letting water spray-out from the back of the pump at the filter union fitting to confirm the pump could move water. So water does seem to flow through which is good for the pump.
When the pump is turned off the sand filter seems to be releasing air.
This indicates an air leak - air getting into the system. Perhaps not enough to cause this whole water flow problem, but it's there.
 

Ashley23!

Member
Apr 3, 2020
19
Alabama
That was the idea Ashley. Letting water spray-out from the back of the pump at the filter union fitting to confirm the pump could move water. So water does seem to flow through which is good for the pump.

This indicates an air leak - air getting into the system. Perhaps not enough to cause this whole water flow problem, but it's there.
So an air leak where?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
You know Ashley, this is a mind bender. IN it's most simple terms, you seem to have ruled-out the following:
- No suction clog by using a temp pipe directly to the pump
- Eliminated suction side air leak using temp pipe above and verifying basket o-ring/plugs
- Verified impeller spins from inside; no apparent debris from the inside of pump
- "Some" water flows, but not enough to maintain prime or provide any significant flow
- Pool was not closed last winter; MPV has not been opened

So there seem to be three "unknowns" to me at this point:
- Possible something is lodged inside the pump around the impeller you can't feel; requires separating the wet & dry ends to inspect
- Something went wrong with the MPV; would have to open to confirm; seems unlikely given the fact it is fairly new. But if the spider gasket failed and somehow got pinched inside, perhaps it is obstructing flow. Removing the 8 screws on top and lifting straight up to inspect would confirm.
- Something is obstructing flow inside the filter. This seems odd as well since the filter isn't that old. Did you ever add any pool store chemicals to the water? Ever use clarifiers or floc? Anything else besides bleach or acid? Did you install the new filter or someone else? An inspection of the inside may be necessary at this point.

Ashley, we always look for the obvious things first, and I think we've done that. Once those obvious things are eliminated, we did deeper. So now you're at the point where you only have about 3 things remaining to check. It's got to be one of those. I guess pick & choose your battle to see which one you want to try and eliminate each one as a potential problem.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
An air leak could be at a fitting, valve, or even the air relief valve. But your filter doesn't seem to have an air relief does it? Maybe at the pressure gauge? You don't appear to have any 3-ways, so perhaps there's a small leak at one of the unions.

I see you also have an auxiliary pump. Pressure cleaner perhaps? Air may be seeping-in from that end. Has that pump been off this while time?
 

Ashley23!

Member
Apr 3, 2020
19
Alabama
You know Ashley, this is a mind bender. IN it's most simple terms, you seem to have ruled-out the following:
- No suction clog by using a temp pipe directly to the pump
- Eliminated suction side air leak using temp pipe above and verifying basket o-ring/plugs
- Verified impeller spins from inside; no apparent debris from the inside of pump
- "Some" water flows, but not enough to maintain prime or provide any significant flow
- Pool was not closed last winter; MPV has not been opened

So there seem to be three "unknowns" to me at this point:
- Possible something is lodged inside the pump around the impeller you can't feel; requires separating the wet & dry ends to inspect
- Something went wrong with the MPV; would have to open to confirm; seems unlikely given the fact it is fairly new. But if the spider gasket failed and somehow got pinched inside, perhaps it is obstructing flow. Removing the 8 screws on top and lifting straight up to inspect would confirm.
- Something is obstructing flow inside the filter. This seems odd as well since the filter isn't that old. Did you ever add any pool store chemicals to the water? Ever use clarifiers or floc? Anything else besides bleach or acid? Did you install the new filter or someone else? An inspection of the inside may be necessary at this point.

Ashley, we always look for the obvious things first, and I think we've done that. Once those obvious things are eliminated, we did deeper. So now you're at the point where you only have about 3 things remaining to check. It's got to be one of those. I guess pick & choose your battle to see which one you want to try and eliminate each one as a potential problem.
Let me ask this, if the sand filter (the hull I will say) has an air leak how would you know? The mvp is new, the spider gasket I checked, only guess would be the hull or tank has a crack I cannot see and water isn’t coming out of 🤷🏼‍♀️

thanks for the help. I just felt like I’ve tried everything and was still just standing in the same place.
 

Ashley23!

Member
Apr 3, 2020
19
Alabama
An air leak could be at a fitting, valve, or even the air relief valve. But your filter doesn't seem to have an air relief does it? Maybe at the pressure gauge? You don't appear to have any 3-ways, so perhaps there's a small leak at one of the unions.

I see you also have an auxiliary pump. Pressure cleaner perhaps? Air may be seeping-in from that end. Has that pump been off this while time?
I was looking for an air relief valve but I don’t think it has one. It does have a gauge which I’ve checked too. The auxiliary pump was here when we bought the home 9 years ago and has never worked and I never replaced it. Should I cap it off?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
If the vessel of the filter had a crack, you would more than likely see water dripping. I don't see that as an issue at this time. In fact, your entire set-up is quite simple: Pump>MPV>Filter. If you have 100% ruled-out a blockage or poor suction (via the temp pipe test), then either the pump is unable to draw water strong enough to supply the system, or their is a blockage after the pump.

Can you tell me the make/model number of your pump please?
 

Ashley23!

Member
Apr 3, 2020
19
Alabama
If the vessel of the filter had a crack, you would more than likely see water dripping. I don't see that as an issue at this time. In fact, your entire set-up is quite simple: Pump>MPV>Filter. If you have 100% ruled-out a blockage or poor suction (via the temp pipe test), then either the pump is unable to draw water strong enough to supply the system, or their is a blockage after the pump.

Can you tell me the make/model number of your pump please?
Blue torrent 1.5hp pump
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
On THIS PAGE you can examples of BT's pump parts breakdown. It's pretty standard really. So can see the impeller and how there is more to it other than just the small part you can feel. I wanted you to see that in case you have doubts about the pump itself or if you decide to pull the wet & dry ends apart to inspect.

I know you did some temp line tests earlier, and you're probably exhausted with it all today. But there's either a restriction from the MPV and/or the filter somewhere, or the pump just isn't pulling water as it should Earlier with the temp suction line, I believe you loosened the union at the filter to see it squirt out. But if you really wanted to test the pump's output, instead of just loosening that union before the filter, actually separate it at the top before the filter and, if you have extra pipe, route it back to the pool. In essence, a circular pipe/path from: Pool > to Pump > to Pool. With nothing in the way, that temp return line should be a gusher. If it's not, you know there is something wrong with the pump. Just in case you decide to try something else tomorrow.
 

Ashley23!

Member
Apr 3, 2020
19
Alabama
On THIS PAGE you can examples of BT's pump parts breakdown. It's pretty standard really. So can see the impeller and how there is more to it other than just the small part you can feel. I wanted you to see that in case you have doubts about the pump itself or if you decide to pull the wet & dry ends apart to inspect.

I know you did some temp line tests earlier, and you're probably exhausted with it all today. But there's either a restriction from the MPV and/or the filter somewhere, or the pump just isn't pulling water as it should Earlier with the temp suction line, I believe you loosened the union at the filter to see it squirt out. But if you really wanted to test the pump's output, instead of just loosening that union before the filter, actually separate it at the top before the filter and, if you have extra pipe, route it back to the pool. In essence, a circular pipe/path from: Pool > to Pump > to Pool. With nothing in the way, that temp return line should be a gusher. If it's not, you know there is something wrong with the pump. Just in case you decide to try something else tomorrow.
Thanks a lot! I will give it a try!