Plumbed 1.5" into a 2" system

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ParrishGuy

Member
Jun 15, 2022
11
Parrish, FL
So this is embarassing... I just realized after reading on this forum that there are union fittings(1.5" inside and 2" slip outside) that allow you to plumb a new pump into both a 1.5" system and a 2" system. Well.. after at least 4 years I realized I plumbed 1.5" into a 2" system. See attached pictures...

I recently added a Pentair Mastertemp heater and when I circulate through the heater I only get 4 of 6 jets blowing bubbles with good flow in the spa. This is what started me looking at restrictions in the system.

Is it worth buying new unions and coming strait out of the pump with 2" pipe? I'm guessing this could help with electrical bill and flow to the spa.

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Welcome to TFP! :wave: Before you go cutting, please post a couple more pics of the entire pad so we can see all the PVC runs. It may make a difference. I'll ask @mas985 to take a peek and see if those connection you made and the sole cause of your pressure loss and jet problems.

Pool Care Basics
 
Those short pieces of 1.5" plumbing have no negative effect on your system. Your pump is 1.5", so taking out an extra 6" won't help anything. It is done all the time.
Google "Bernoulli principle" for the science. Rest easy.
 
1poolman1 said:
Those short pieces of 1.5" plumbing have no negative effect on your system. Your pump is 1.5", so taking out an extra 6" won't help anything. It is done all the time.
Google "Bernoulli principle" for the science. Rest easy.
Click to expand...
Great news! Thank you.

I still have the flow issue once I route through the heater with 4 of 6 jets blowing good. Should I replace this return check valve with a flap style?
 

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An issue you have is all the 90's in the system. Is the valve after the filter a heater bypass? The check valve appears to be in use when the valve is turned the other way, which appears to be when you are heating your spa. (If it is broken, replace it with a repairable one) If that is the case, I count 16 - 20 elbows in the plumbing up to the pool/spa return diverter valve. That is just after the filter. There appear to be 9 from the pool/spa suction valve to the pump and filter not counting what is under ground. Let's call it 27 total above ground. Then add the restriction of a filter, heater, SWG cell and you have a lot of restriction to flow.
The Hayward Super Pump is one of the most popular pumps ever made, they are everywhere. But, they are a medium-head pump, designed to move a lot of water, but not against a lot of restriction or "head." You may be asking your old pump to do more that it is capable of doing. A high head pump may solve the problem.
 
1poolman1 said:
An issue you have is all the 90's in the system. Is the valve after the filter a heater bypass? The check valve appears to be in use when the valve is turned the other way, which appears to be when you are heating your spa. (If it is broken, replace it with a repairable one) If that is the case, I count 16 - 20 elbows in the plumbing up to the pool/spa return diverter valve. That is just after the filter. There appear to be 9 from the pool/spa suction valve to the pump and filter not counting what is under ground. Let's call it 27 total above ground. Then add the restriction of a filter, heater, SWG cell and you have a lot of restriction to flow.
The Hayward Super Pump is one of the most popular pumps ever made, they are everywhere. But, they are a medium-head pump, designed to move a lot of water, but not against a lot of restriction or "head." You may be asking your old pump to do more that it is capable of doing. A high head pump may solve the problem.
Click to expand...
Thank you for the reply...

Yes, the check valve is after the exit of the pentair heater so water doesn't backflow into it(obviously). The heater is bypassed when not in use. I have no automation and will manually change valves and turn on heater when using the spa only(no interested in heating the pool). My spa did heat up to 100 degrees within 30 minutes or so but the heater would kick on and off during the process. Would it help to not run all of the water throught the heater? I could leave the valve slightly open so some skips the heater.
 
Not running all the water through the heater may cause the pressure switch to "bounce" and not stay closed, exacerbating the issue. The heater "kicking on and off" may be a flow issue and you don't want to reduce it.
 
1poolman1 said:
Not running all the water through the heater may cause the pressure switch to "bounce" and not stay closed, exacerbating the issue. The heater "kicking on and off" may be a flow issue and you don't want to reduce it.
Click to expand...
Ok, thank you. How much of an effect would replacing that check valve with a new swing valve with the removable top? I can only reduce one 90 with the outlet from the heater if I rearrange everything.

I do plan to move to a VS pump within the next year just fyi.
 

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ParrishGuy said:
Ok, thank you. How much of an effect would replacing that check valve with a new swing valve with the removable top? I can only reduce one 90 with the outlet from the heater if I rearrange everything.

I do plan to move to a VS pump within the next year just fyi.
Click to expand...
The valve you have appears to be this:
www.wildwestpoolsupplies.com

Flo Control Swing Check, True Union 2"Sxs Clear | 1720C20

Get the 1720C20 Flo Control Swing Check, True Union 2"Sxs Clear here. Save on tons of great hot tub / spa products plus receive top-notch service with Wild West.
www.wildwestpoolsupplies.com www.wildwestpoolsupplies.com
You should be able to see the name somewhere on the body. Easier than a re-plumb.
 
1poolman1 said:
Not running all the water through the heater may cause the pressure switch to "bounce" and not stay closed, exacerbating the issue. The heater "kicking on and off" may be a flow issue and you don't want to reduce it.
Click to expand...
I'm going to route the water through the heater to heat the pool and run the heater to see if it shuts on and off. Maybe I can narrow it down to just restriction when routed to the spa.
 
1poolman1 said:
The valve you have appears to be this:
www.wildwestpoolsupplies.com

Flo Control Swing Check, True Union 2"Sxs Clear | 1720C20

Get the 1720C20 Flo Control Swing Check, True Union 2"Sxs Clear here. Save on tons of great hot tub / spa products plus receive top-notch service with Wild West.
www.wildwestpoolsupplies.com www.wildwestpoolsupplies.com
You should be able to see the name somewhere on the body. Easier than a re-plumb.
Click to expand...
So you think that would definitely increase flow compared to the spring loaded one I have that pushes open a poppit valve?
 
ParrishGuy said:
So you think that would definitely increase flow compared to the spring loaded one I have that pushes open a poppit valve?
Click to expand...
Can't increase, but less decrease if the check valve is the issue. You may find that the "gate" in the existing valve has broken loose. Most springs start at 1/2#. It takes far less than that to open a swing-check valve. Water pressure will keep it closed.
 
1poolman1 said:
Can't increase, but less decrease if the check valve is the issue. You may find that the "gate" in the existing valve has broken loose. Most springs start at 1/2#. It takes far less than that to open a swing-check valve. Water pressure will keep it closed.
Click to expand...

Ok, for $50 I'm definitely open to trying the new one. I have removed the current check valve and the spring is still there and I can push it forward to open and when I let go it closes shut but it's literally like a 1" hole when the valve is open.
 
ParrishGuy said:
I'm going to route the water through the heater to heat the pool and run the heater to see if it shuts on and off. Maybe I can narrow it down to just restriction when routed to the spa.
Click to expand...
I just went out and routed through the heater when circulating through the pool only(no spa) and pressure went from 10psi to 20psi and the heater kicked on and off maybe every 3 minutes just like it did with only the spa on. When routed to only the spa pressure goes to 23-25psi.
 
When your spa is "on," all the water is now restricted to the 4 to 6 jets (normally) that have 1/4" - 3/8" orifices in them. Its like putting your thumb over the end of a garden hose. The pressure in the hose increases, the flow from the hose decreases.
A 10# rise in pressure with the heater on indicates that there another issue going on, that's a 23.1' increase if head. Could be in the plumbing, could be in the heater. According to Pentair, the heater should only add about 7'.

Loose definition of a medium-head pump is a pump that has its flow drop off 20% or more on a 10# rise in the pressure indicated on the filter. (Sta-Rite Pool Hydraulics School, 1993) That rough definition hasn't changed. A Super Pump is a medium-head pump.
 
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1poolman1 said:
When your spa is "on," all the water is now restricted to the 4 to 6 jets (normally) that have 1/4" - 3/8" orifices in them. Its like putting your thumb over the end of a garden hose. The pressure in the hose increases, the flow from the hose decreases.
A 10# rise in pressure with the heater on indicates that there another issue going on, that's a 23.1' increase if head. Could be in the plumbing, could be in the heater. According to Pentair, the heater should only add about 7'.

Loose definition of a medium-head pump is a pump that has its flow drop off 20% or more on a 10# rise in the pressure indicated on the filter. (Sta-Rite Pool Hydraulics School, 1993) That rough definition hasn't changed. A Super Pump is a medium-head pump.
Click to expand...

So if there are no clogs or abnormal scenarios with the plumbing, I need a high head pump to solve the problem?
 
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth. - Sherlock Holmes.

I believe we have discussed most, if not all the possibilities. If you can rule out restrictions in the areas discussed, that's what's left, a different pump. If you can't change the plumbing, but can replace the check valve, its cheaper than a pump. If it doesn't work, it didn't cost a lot and you eliminated that as an issue. To give it a try, rip the innards from your existing check valve and try with just the body in place. You're going to replace it (and I doubt it is really needed). Best I can do from a keyboard.
Click to expand...
 

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