Little to no filter tank pressure and poor suction

[mreidnz]

I have been having trouble recently with poor suction.

Symptoms:

• low suction. Not enough to drive pool cleaner (I have a Zodiac MX6 In-Ground Suction Side Pool Cleaner)
• Triton 2 sand filter not pressurizing. Pressure gauge less than 5 psi
• No apparent air in the strainer housing

Here are all of the things I have done recently.

• replaced all O-rings/seals on the pump and housing
• replaced the "Push-Pull" backwash valve for a side mount multiport valve
• used a hose and back washed the suction side pipes to make sure there was no blockage
• replaced the pool vacuum hose
• also replaced the tank pressure gauge
• replaced the pump impeller
• emptied old sand and cleaned inside of filter tank and replaced with filter balls

Everything was working well and the water was about the best it has ever been, but about two weeks later it seemed to lose suction.

If I backwash, the flow is powerful and this seems to get the pool cleaner moving nicely. However, the cleaner stops again after about 15-30 minutes.

Any assistance or advice will be much appreciated. Thanks in advance

 

[Texas Splash]

Welcome to TFP! Can you post some pics of your equipment pad from various angles?

 

[mreidnz]

Thanks Pat. I have attached some pictures of the equipment. I hope it is what you were asking for. Thanks again

 

[Texas Splash]

Well shoot. I was thinking (hoping) perhaps it was as simple as the lines going to the filter might be backwards, but that's not the case. How old is your pump?

 

[mreidnz]

The pump is quite old. Probably 15 years or more. However, when backwashing it is a powerful flow so I assumed it couldn't be the pump. When I return the multiport valve back to filter mode after backwashing (clear water by the way), the tank pressure increases to MAYBE 10 psi but then slowly reduces and the suction reduces again.

I don't see any air in the strainer housing, but I am wondering if I may have a suction side issue under the ground from the pool to the pump.

 

[Texas Splash]

From your notes above, was this happening before you changed to the new MPV, or did it start after the swap?

 

[mreidnz]

It was happening prior to the change as well. I had an old push-pull valve that was leaking and a bit of a mess which is why I decided to change to the multiport. When first changed, everything worked great and I thought the issues were solved. Sadly it all returned to the way it was before after a week or two...maybe worse because I never had any tank pressure issues in the past.

Thanks for giving it some thought.

 

[Texas Splash]

I'm going to tag @JamesW for a fresh look at this since you did so much noted in Post #1 already.

 

[JamesW]

The multiport says DE filter.

It's the wrong multiport.

 

[JamesW]

 

[JamesW]

This is correct for a sand filter.

Pentair 2" Threaded Multiport Valve for Sand and Quad D.E - 261055 - INYOPools.com

261055 - 2" Threaded Multiport Valve for Sand and D.E

www.inyopools.com

 

[mreidnz]

The multiport says DE filter.

It's the wrong multiport.

Hi and thanks James. That's interesting. I was told that the only difference was the max pressure it could handle but that this would do the job because it could manage up to 50 psi and my system never goes that high. Do you know what the difference is?

 

[Texas Splash]

It's the wrong multiport.

Right in front of our eyes. I knew it was time for a fresh look. Thanks James.

 

[Texas Splash]

It was happening prior to the change as well.

Now after changing the MPV we would be curious to know if that same issue continues.

 

[JamesW]

Do you know what the difference is?

The inlet and outlet are reversed.

You are pushing dirty water inside the laterals and clogging them up.

You are basically running in backwash mode.

 

[JamesW]

It was happening prior to the change as well.

Maybe that was plumbed backwards.

 

[JamesW]

The bodies of the valves are different that's why you can't just reverse the other parts.

DE on the left, sand on the right.

 

[mreidnz]

So if there were a way to plumb it the other way around could that work? Not saying I will, but I'm wanting to make sure I know all of the options. Thanks again

 

[JamesW]

Time for A New Filter?

Before spending $1,000 for a new filter (I'd do the installation), I thought I'd run it by the experts to see what you'd do. First, it's a Pentair Tr100 Triton II and is likely 25-30 years old. (Bought the house 6 years ago.) Second, I've been getting sand in the pool for the last couple of...

www.troublefreepool.com

 

[mreidnz]

So if there were a way to plumb it the other way around could that work? Not saying I will, but I'm wanting to make sure I know all of the options. Thanks again

The bodies of the valves are different that's why you can't just reverse the other parts.

DE on the left, sand on the right.

View attachment 446004

Ah...so it is an internal thing. I understand now. Thanks. So basically, whatever the issue, I will need to make that change to the correct multiport correct?