Plumbing does not reach new pump

[highendman2]

Hello,

I'm looking for the best solution to my problem.  I recently replaced my old pump with a new version of the same model. 4 HP Waterway Spa Pump: 2" in/out Side Discharge 56 Frame-240V .  The original was made by GE with the same specs, same dimensions and same model number.

The distance between the mounting holes and the pump intake on the new pump is about 3/8 of an inch shorter.  The plumbing barely reached the old motor and does not reach the new one to even get the threads started.

I've found a threaded pump union extender (1.5x.75") http://www.hotubparts.com/plumbing-union/threaded-pump-union-extender-1.5-x-.75/.  I asked a man who sells it and he informed me that the part would not work.  It looks like it would work, except for the flow restriction. With a 1.5" opening instead of a 2" opening, the intake flow would only be 3/4 or the original (assuming the part would work). 

What would be the easiest effective way to get this back together and working?  I'm a novice with hot tubs (our house came with the tub and we really enjoy it)

Thank you. 

[Tman122]

I don't think the guy is telling you it won't work. To me it seems like he doesn't want you to effect the longevity of the pump. Any reduction in suction or outlet flow will effect pump/motor longevity.

Any way to go back on the 2" suction line and cut out a 3-4" long piece. Then get a new piece 3/8" longer than the old one and a couple couplers and glue it in?

[Dr. Spa™ Ret.]

Are you saying that because of how the new pump bolts down to the plywood base, the plumbing wont reach?

MOVE the mounting bolts or simply add new ones.

[highendman2]

Thank you for the replies.

The mounting bolts are on the tub itself.  It does not seem practical to change those - I would have to work from underneath the tub.  I had thought about cutting them off and then attaching the plumbing and then gluing down the pump, but that seems impractical.

I have watched a video on plumbing alterations, but am not confident with it.  The plumbing used on our tub is different from what I've seen in the videos -- it's corrugated.

It seems by best option is to get the adapter and see how it affects the flow.  Unfortunately, it's not easy to access the pump because the previous owners of the house (who assembled the tub), put the motor up against the wall making it inaccessible.  I had to drain the tub, then get two guys to help me lift it  up onto the tiles and then slide it out from the wall in order to access the pump.  This also means that I have no easy way to check for leaks or proper functioning unless I leave the tub away from the walls and half up on the tiles, then drain it again when I want to move it against the wall.

I have pictures of the gap in the plumbing, but didn't see an easy way to attach it on my post.

Thanks again.

[BullFrogSpasMN]

That adapter won't work, nothing reduced down to 3/4" in size should be adapter or "plumbed" into a jet pump so the gentlemen you spoke with was correct...post some images of the pump and surrounding space and I could provide advice

[Tman122]

Thank you for the replies.

The mounting bolts are on the tub itself.  It does not seem practical to change those - I would have to work from underneath the tub.  I had thought about cutting them off and then attaching the plumbing and then gluing down the pump, but that seems impractical.

I have watched a video on plumbing alterations, but am not confident with it.  The plumbing used on our tub is different from what I've seen in the videos -- it's corrugated.

It seems by best option is to get the adapter and see how it affects the flow.  Unfortunately, it's not easy to access the pump because the previous owners of the house (who assembled the tub), put the motor up against the wall making it inaccessible.  I had to drain the tub, then get two guys to help me lift it  up onto the tiles and then slide it out from the wall in order to access the pump.  This also means that I have no easy way to check for leaks or proper functioning unless I leave the tub away from the walls and half up on the tiles, then drain it again when I want to move it against the wall.

I have pictures of the gap in the plumbing, but didn't see an easy way to attach it on my post.

Thanks again.

Google cutting and glueing flex tubing.

[highendman2]

Bullfrog, the adapter screws onto the 2" input and is 3/4" in length.  It's opening is only 1.5" for some reason.

What's the easiest way to post pictures here?

[Tman122]

The adapter is only 1.5 because you need some meat to create the threads that mate with the pump. If you look at it you will understand. Any reduction in flow will cause premature pump failure. Does that mean in a week or a month? No. But it could mean 3 years instead of 4 years, 4 years instead of 6 years or 6 years instead of 10.

I still say lengthening the input further back from the pump is your best bet. The pump is a little shorter. It's not an uncommon problem even if the skews were the same. That's why a lot of us are plumbers. That flex hose can be glued.

https://www.youtube.com/watch?v=z33Oh9uxV5Q

[bud16415]

I don’t know if that restriction would shorten pump life or not as the pump and motor are designed to pump against head pressure that is normally caused mostly at the jets. I would say it will most defiantly reduce the force of the jets. If there is the opportunity to shorten the output pipe and do the connection without the restriction as Tman122 suggests that would be a much better way to do it.   

[Tman122]

I don’t know if that restriction would shorten pump life or not as the pump and motor are designed to pump against head pressure that is normally caused mostly at the jets. I would say it will most defiantly reduce the force of the jets. If there is the opportunity to shorten the output pipe and do the connection without the restriction as Tman122 suggests that would be a much better way to do it.

You are correct however, head is different on the suction side. If there is just enough output head currently for the correct most effecient operating rpm, restricting the suction head will effect pump cavitation which is detrimental to longevity. Head pressure effects effort (leads to hotter operating temps) Cavitation can happen because of suction head restrictions which causes over revving (also causes overheating) The cooler you can run the pump the better for longevity. Most of the higher end manufacturers actually measure and optimize heads. And yes both effect jet feel one way or the other. I guess you could try the adapter and see what your pump says? Might be fine. Or it might not? You will hear it cavitating.

[highendman2]

Thanks for the replies guys.  I'm going to try to do it right, especially since it is difficult to correct once it's back together (involves a pump drain and moving the hot tub as well.)