Spa won't bubble / agitate after replacing Single-Speed with VS pump

[finding.nemo]

First post, thanks in advance for any help you can provide on this issue.

I replaced my 9 yr old single-speed 2HP pump with a new Pentair VS 3HP pump (11018).
I've got it hooked up to a Zodiac (Jandy) iAqualink kit and everything is working great.
That is everything except when I run the spa mode, even at max speed (3450 setting), the spa doesn't bubble like it did before, and the pressure coming out of the jets is unimpressive. The outlet jet covers are spinning like crazy, but no bubbles.
if I put my hand over one of the jets, a few of the jets start to mimic the bubbling/jet action I expect, but still not anywhere near what it was.

A couple other points.
1) I rebuilt much of the 2" piping to locate the new pump and relocate my booster pump in the same area, the design is pretty close to the original but is different from before.

2) My filter is the Pentair clean & clear 420 (with four cartridges)

3) With my old pump the needle on my filter pressure gauge would always register "1" on the gauge (out of 5), with the new VS pump at full rpm the gauge bumps up to a reading of "2", and the pressure from the filter relief valve on top is like a fire hose. So the pressure is certainly there and greater at the filter than ever before. When I dial down the variable speed, the water pressure on the filter gauge drops accordingly.

4) Between the filter and the spa the line goes through an old check-valve that I did not replace during the reconfiguration (reused that portion of the pipe) then it goes through the heater unit.

Finally, with water pressure in the filter being so strong at full speed, my only thoughts are that the check-valve went bad, something is clogging the pipes, or the difference between the old and new pump somehow makes a difference on the bubbling effect.

Looking for input on how to troubleshoot this effectively.
Thanks.

 

[jblizzle]

If you dial the new pump to measure the same thing on the filter pressure gauge (what the heck does 1-5 mean? usually they are in psi), the you should have almost identical flow to what the previous pump had (if the plumbing was the same). So .... something had to have gotten changed between the filter and the spa.

How is the flow in pool mode? You should be able to get the same and higher flow than you did with the old pump.

Can you post up some pictures of your equipment and plumbing? How To Post Pictures

 

[mas985]

The outlet jet covers are spinning like crazy, but no bubbles.

That points to a problem in the air vent. Was that plumbing changed at all? Do you have a blower and is it working?

 

[finding.nemo]

Yes, the gauge is odd, measured in kg/cm squared, must be replacement from previous owner.
Never gave it much attention as the old single-speed pump always was pegged at the 1 mark and ran great (just expensive)
Its a good gauge for "spinal tap" references (this one goes to 4.2).

Truth in advertising...Another item I just noticed is the constant quarter-sized air bubble in the pump's filter basket.
After reading a few posts about air bubbles, I'm concerned this is impacting the pump's performance and is related to my spa bubbling issue.
I'm going to try the shaving cream trick in a few places and also check the seals on the pump lid and plugs.

pics of pad with equipment coming soon. thx.

 

[mas985]

A quarter sized air bubble in the pump basket is not an issue.

 

[finding.nemo]

Interesting about the blower...I have one hooked up to my Aux-4 but never used it on the old single-speed pump because the spa action with the pump alone was quite enough. when I did run the blower it was way, way too much to the point of ridiculous...so we never used it (even my teenage kids thought so!). I'm certainly considering it now with my vs pump, but confused why new vs pump that can run at 3450 rpm doesn't come close to matching the spa bubbling action of my old single-speed pump that ran at 3450 rpm.

 

[JasonLion]

Have you tried turning down the new pump little by little to see what happens? The jets might be having problems because there is too much pressure.

 

[mas985]

During the installation of the VS, something might have gotten into spa plumbing. You mentioned that the VS has higher pressure which would indicate a partial blockage in the spa jets. You might try removing the nozzles which are deep within the spa wall. A long 9/16" socket wrench is usually required. Once removed, turn on the pump and flush out the lines.

 

[finding.nemo]

Yes, the 2" plumbing was rebuilt, but the design remains the same. I added a straight pipe to feed the intake (per pentair's priming requirements) as my old design was basically feeding the intake with a 45 degree elbow. I had to add a new 3-way jandy never lube valve in front of the pump for the pool and spa intake pipes. The previous setup offered no room to maneuver, no pipe to cut, so I had to start basically from the two pipes coming up into the pad.
Here's a pic of the setup, not thrilled having the 90 elbow in the mix but didn't have much choice with room available.



- - - Updated - - -

will try the line flush, thanks for the tips!

 

[finding.nemo]

Good news: problem solved!
Bad news: problem self-inflicted (guessing not so uncommon)

As I mentioned in an earlier post about my unnecessary Aux-4 blower, I wound up cutting it out for the time being to re-position my new vs pump and my old booster. While doing that i thought it would be a great idea to cap the the cut 2" pipe for the blower. Little did I realize that somehow that pipe (even though not being powered by the blower) still had a significant impact in providing air to create the spa bubbling action. The pipe is part of this unusually tall loop (see pic). If you notice the end of that loop it is now uncapped, which prior to this post I had fitted a 2" end cap on. Is there an official name for this setup? interesting effect.

Thanks to all that provided input and challenged me to examine everything a little closer...found it!

 

[mas985]

That is the air vent for the venturi's and the pipe is where the air comes from in order to make the bubbles at the spa jets and why I asked earlier if you had modified that plumbing. So yes, that needs to be open so air can enter into the pipe.