2" piping but 1.73" (inside) fitting

[masupilami]

Hi there,

I'm currently upgrading my (single speed) 1.5" pool pump to to a new 2" inch (variable speed), and all my current plumbing and pipes are 2", except the connection from the current pump to the remaining system. So my current pump goes via 1.5" pipe to the 2" of my high volume filter, and sucks water in from a 1.5" elbow (suboptimal already) and 1.5" ball valve that connects to 2" piping.

Because I want to have it all properly 2", I've planned to replace all those 1.5" elbows and piping with 2" flex (soft bend, because >3ft to both sides) PVC hose .. (different one than you have in the US.. way more rigid and pressure resistant here in Thailand). I'm going with the flex to get rid of the vibration noise in my house I've had in the past, since the pump is sitting on my basement concrete (no worries about leakage, it would drain out there, since I'm on a hillside).

I've just received the fittings I've ordered and noticed (and not thought about before), that while the threaded side is 2" inside, it narrows down to 1.73" on the side where the 2" hose slips on.. but that "narrow" part is just 2" long.

While it seems to be not ideal, is that something I should be concerned about? Would that actually cause a problem in the flow I should worry about? I have 4 of those fittings to connect the pump on both sides.

I would need to find a 2" fitting with a 2.5" slip on instead, and order a new 2.5" hose - which I couldn't find so far. Seems they only make those in 2-3-4... so I would need to use a 2" threaded fitting, go to 3" and connect a 3" hose and go back down to 2" on the other side.

PS: I tend to overthink/overengineer things.. so.. maybe same situation here

Thanks

 

[HermanTX]

You will find that a VS pump is much quieter and will cause less vibration. Also, you could place it on a door mat or similar material to reduce any vibration. However, if you are set on using flexible piping rather than just Sch 40 2” pipe, the minor reduction to 1.73 is still bigger than the ID of 1.5” PVC and will not affect the flow performance and most likely the use of flexible pipe avoids the need for 90 deg elbows which cause more flow disruption when using hard piping.
Good Luck.

 

[masupilami]

after 4 hours on google I've found the perfect fitting ..

in case somebody ends up at this post and is looking for something similar

SPEARS VALVES 1436-252 Reducer Male Adapter, MPT x Insert, 2 x 2-1/2 Size, PVC​

... unfortunately $25 per piece, plus very limited availability (shops)

since I would need four of those, plus shipping + customs from the US to Thailand (which would probably add another $150 on top) I'll stick with my 2" MPT to 2" hose for now.

If the new pump is as quiet as everybody keeps telling me (and I hope that's true, because that's the main reason for the upgrade), I'll probably switch back to hard 2" PVC at some point anyways.

 

[HermanTX]

You will need to find the best speed for your pool and plumbing. Vast majority of us with SWCGs will run in the 1200 to 1700 rpm range. You will need to find the minimum speed that activates your SWCG, then add 100-200rpm to that to account for variables such as dirty skimmers or filter. Good Luck with the plumbing and new equipment.

 

[masupilami]

I'm torn between going hard pipe or hose. I've just tested the fitment of my new fittings with the new hose (not installed) and noticed the fittings slip in and out of the hose super easy, so I have to tighten those hose clamps quite a bit - which results in mayor bending on the inside wall of those plastic fittings. I wouldn't have a good feeling using those, and since they are probably made in china there is no information to be found for what pressure they are supposed to be... but if I compare the thickness of the side slipping into the hose to the wall thickness of the PVC pipe they are super thin. Unfortunately they're the only ones I could find here in Thailand, except 304 stainless steel ones, which are probably a bad idea for salt water.



My thought is now, to probably go with 2" fixed pipe first
- upgraded from the current 1.5"
- no elbow right at pump inlet - at least 5x2" straight first
- replace the crappy spring check valve with proper flap one
- and of course the 3HP variable speed instead of 1HP single speed

... then see if the vibrations (buzzing) with the new intelliflo are noticeable in my living room again (which is right above the pump) and only if so, try to find better hose fittings. Worst case I gonna waste about $80 on the fixed pipe fittings / unions, if the hard pipe transfers noise again, but if there is no buzzing issue any more (why I bought the intelliflo vsf in the first place), it's definitely the better and safer way to go (long term). Looking at some YouTube videos there should be like zero vibration at 1200 rpm?

With the current 1HP Hayward Super II Pump the original installer had hard pipe, and when I've put the pump on 2" rubber-corc blocks before, it didn't change anything about the noise. The intense vibration kept going via the pump outlet into my huge sand filter, which is sitting on concrete and I could feel the strong vibrations when touching the filter (or any pipe anywhere). From there they went into the whole house, since that's all sitting in my basement and it's all concrete here.



Based on my request that "I want a flex hose there", a different guy (no pool installer, because qualified ones seem impossible to find here) then simply cut the 1.5" connection between the pump and the filter, and slipped a 2" rubber hose (without any rigid stabilization) on that 1.5" pipe endings and clamped it down. He did the same on the suction side of the pump, but since it has no stabilization, it of course collapsed at first and he decided to put a piece of 1.5" inside that hose - which made it way less effective and I have still a lot of vibration on the pipes connecting that side. The later also made me realize that this guy has not much clue what he's doing, and I should take matters in my own hand from now on.



Even it looks like "a bit of a hack", it was a huge success, because the buzzing in my living room went down by like 90%, and the buzzing when diving in the pool is completely gone (before you could hear the loud buzzing when underneath the water). Also the general noise of the pump in my basement went down by at least 50%.

I run it like that since mid 2020 - only the hoses went a bit foggy.



Opinions? Thoughts? Suggestions?

 

[HermanTX]

I believe the VS pump running at 1200 to 1700 rpm will help a lot to reduce the vibration. Also, you can put a mat under it to be a cushion between the pump and the cement floor to help soften it as well. One other item, looking at your equipment room. Can you add in foam insulation in the wall opening where your pipes go through the cinder block wall? Not sure if that is available in Thailand but again trying to reduce all possible areas where vibration may be transmitted.
From a safety standpoint, I like that you are going to Sch 40 PVC hard pipe.
Use unions on both sides of the VS pump.
Have 10 inches of straight pipe before the pump inlet and also before the SWCG. The recommendations is 5x the diameter of the pope.

 

[masupilami]

thanks for your input, I really appreciate it

Also, you can put a mat under it to be a cushion between the pump and the cement floor to help soften it as well

the pump is already sitting on 2" thick rubber cork blocks (made for that use case) and I'll definitely keep those.. main problem was/is, that the vibration is transferred via the pipe to the sand filter, which is too heavy to put any rubber underneath. But as you already mentioned, I expect (and hope) the InelliFlo to have way less vibration and friction in the first place, via the magnetic drive and the 2".

Can you add in foam insulation in the wall opening where your pipes go through the cinder block wall?

the pipes are bolted onto the concrete at some points, so the holes where the pipes go thru the bricks don't make any difference, but they're already filled with spray foam. Main source/connection/transferpoint is the sand filter.

Use unions on both sides of the VS pump.

definitely the plan. will get 4 unions, so if the hard piping does not work, I can easy switch it to a hose concept on both sides of the pump, without cutting anything.

 

[Julianl50]

Look into Eva vibration pads. I used some for my heat pump water heater. Very good isolation.

https://www.supplyhouse.com/DiversiTech-MP-2E-EVA-Anti-Vibration-Pad-2-x-2-x-7-8

You can find larger versions.

I imagine you could fashion a base for the sand filter. HDPE sheet with vibration pads in between.

 

[masupilami]

done.

that intelliflo is INSANELY quiet - why in the world would anybody ever install such a stupid Hayward Super II pump, which was a thousand times more nosy and burning electricity like crazy too.

Looking at the price, the intelliflo is only double of the heyward - but I guess that was probably different 6 years ago, when the original installer installed everything. But I've also learned that those pool experts here around my area only know one solution only and keep repeating it - most never heard of a variable speed pump.

The cork blocks were totally obsolete.. there is ZERO vibration or noise anyways.. but have to keep it like that now, due to the pipe length.

I'm glad I never messed with that stupid flex pipe Crud, and went hard pipe

 

[HermanTX]

The cork blocks were totally obsolete.. there is ZERO vibration or noise anyways.. but have to keep it like that now, due to the pipe length.

I'm glad I never messed with that stupid flex pipe Crud, and went hard pipe

Glad it all worked out and it all looks great the way it is set up.
Maybe you can be an advocate for use of VS pumps to pool builders in your area.

 

[masupilami]

Maybe you can be an advocate for use of VS pumps to pool builders in your area.

I'll definitely gonna do that. Still need to figure out the right RPM value(s) to have a working real world example on how much energy it saves, while keeping the same water quality or even improve it.