Need to replace 10 year old spa air blower

[pgershon]

I have a pool/spa where each has its own plumbing. The spa has its own filtration, but also 8 jets which are fed by 2 2-hp pumps. In addition, I have a GAST "regenerative" commercial air blower which is a large cast iron unit and I believe overkill for my application. The GAST blower did not work at the start of last season and was going to be replaced, but then it suddenly came back on. This year it did not start again, and as I was hoping it would get going, the motor blew out (I saw the smoke, and it now trips the breaker whenever I power on). So I need a new unit.

Replacing the GAST is very heavy and expensive, and as I said, I dont believe I need something that big. Spa blower gets used at most 20 mins a day, maybe 4 days a week in the summer - and on average much less than that. The commercial blower is designed for continuous use.

Any recommendation for a replacement? I am looking at the Air Supply of the Future Silencer (Air Supply Blower 2 HP 240V Silencer | 6320220) for less than $200, as opposed to the GAST which is over $1700. I believe my current unit is 230V 2.5 HP, although the label has worn off so I am not 100% sure if its size.

Silencer - https://www.airsupplyflorida.com/wp-content/uploads/2013/09/Silencer-Flyer.pdf​

Any thoughts on the Silencer or a different replacement?

I believe I would install the new blower 1-1.5 feet above grade piping PVC to an elbow attached to the existing check valve. Part of the issue with the existing blower is that it sits at grade and gets water and dirt inside, which cannot be good for it.

 

[kimkats]

I am not sure of the answer but here is a bump to get more eyes on it.

 

[1poolman1]

Residential air blowers should be installed to a vertical pipe (they are never glued) with a check valve installed after the blower. Some come with them and some have them as an internal part.
Each blower's instructions will tell you how far above water level the blower should be. There are also sizing requirements based on the number of jets or the bubbler you have.

 

[pgershon]

So if I have 8 jets powered by two 2HP pumps (4 jets per pump), how do I determine appropriate size of air blower. I have a commercial regenerative 1.5 HP GAST blower now. My former pool company was going to replace it with a 2 HP Silencer blower last year before the old one started working again.

 

[1poolman1]

2hp and 8 jets sounds right as long as it feeds all 8.

 

[pgershon]

So the install is just repiping to be vertical and moving the electric from old to new. Sounds relatively easy. I wish I could find a manual for the Silencer so I had a better idea of what I am dealing with.

 

[Turbo1Ton]

Here is the manual I found on the web for the silencer air blower, when my pool was built.

 

[pgershon]

Thank you. I guess I found that document too. I am not clear from it how the unit is supposed to mount, since its orientation is so different from my current. Does it mount on a wall or does it just sit at the top of vertical PVC pipe? I am wondering how it is kept stable. Might you have a photo of your set-up? Thanks very much.

 

[Turbo1Ton]

I believe they come with a bracket that can be mounted to the wall. My PB did not install it like that. It just sits on top of the 2" PVC pipe. I believe most of this type of blower just sit on top of the pipe.



You can see it to the right of the filter. It is near the wall but not mounted to it.

--Jeff

 

[1poolman1]

Sits on the pipe. You can support it if you want but not necessary. Many (most) are just sitting on the air pipe. Some have clamping screws through the collar.

 

[pgershon]

Got it. Thank you. I will post a photo when my unit arrives and is up and running.

 

[pgershon]

I got my new Silencer installed today. It worked for close to 10 minutes, then shut down. It seemed too work again tonight when I briefly tested, but it was too dark to really analyze. Any ideas why this air blower might shut down so quickly? Could it be one powered for my spa?

 

[Rancho Cost-a-Lotta]

Check out the wiki link below. It's possible your blower is overheating. You can install a tee and ball valve and experiment by bleeding off some of the outgoing pressure. It can be a bit loud, but if it works, there are options for muffling the sound. The fitting and ball valve should be less than $15.

Spa Air Blower - Further Reading

www.troublefreepool.com

 

[Rancho Cost-a-Lotta]

Side note. No reason to glue the fitting and ball valve. Just press fit them in place. If it doesn't work, you might be able to return them.

 

[pgershon]

Thanks for the suggestions. I am going to do more troubleshooting today. Two likely issues come to mind and perhaps a third, and I am not sure how to rule out one versus the others:

1) Could be too powerful motor, as you suggest. I can add a T and ball valve and see if it helps.
2) Could be air obstruction. The prior commercial blower blew horizontally and not vertically. As a result, the pipe came from the ground with a 90 degree turn to get to blower. I kept that in place and added another 90 degree turn to get my pipe vertical. I did this to get the unit by the wall of my pool house, but I could correct by removing the two 90 degree turns and just having one straight run (there are undoubtably other turns with the piping system underground that I cannot see.
3) When I cut the old blower off from the PVC, I could see lots of water in the lines that obviously should not be there. This water could be causing obstruction making the blower's job harder. From reading this side, I presume the Hartford loop above the water line and near the spa is supposed to help keep water out. I do not believe I have this. The spa is piped underground (and in concrete) and there is nowhere above ground or above the water where a loop could be. The pool equipment is about 25 feet from the spa which makes me think its borderline as to the need for a Hartford Loop. System ran as is for last 12 years with GAST blower.

 

[Turbo1Ton]

For what it's worth, I use my silencer blower to clear my main drain lines in when I winterize my water features. I think there is enough volume and pressure to clear any moisture from the line, but maybe not. And mine also elbows out of the ground at the edge of the equipment pad, and then runs ~2' and then elbows up to get it in its final location. I don't think the elbows are the issue.

--Jeff

 

[pgershon]

Tried a few things today and there is a problem in my system, though I think probably not with the air blower itself.

1) With air blower on without the jet pumps running, all 8 of my jets bubble, just as they did before.
2) With jet pumps alone, I get virtually no bubbling. Pretty much the same if silencer blower is connected or if I leave the unit off and pipe open.
3) When both units run together, sometime the jets blow like they should, but it shuts down quickly - the silencer is timing out - presumably some high temp failsafe kicks in.
4) I looked at the check valve to see if it was working. I took off silencer and pressed down on check valve as if air were coming from silencer, and lots of water came flying up the pipes (with jet pump running).

I am speculating that when the jet pump runs, it is causing water to back up into the piping for the blower. The blower cannot handle the load of fighting all the water and craps out. It would not surprise me if my old pump blew out fighting the same water pressure. But is this normal? And if not, how can I correct it? I have owned the house and pool since 2001 so the plumbing used to work, and nothing has been done to in since 2011.

I tried removing the jet heads and running the system without them in case there was a blockage. Pumps and blower ran fine on their own, but same issue when I run both together. I believe I need to determine cause of back pressure - water flowing up air pipe.

 

[ajw22]

What model is your jet pump that is pumping water into the spa jets with your blower?

 

[pgershon]

I have two Century 2 HP motors (Hayward housing - replaced last year). Each pump controls 4 jets, and one blower is for all 8.

Pumps are UST1202 C-Face 2HP Single Speed Up Rated 56J Pool Filter Motor

 

[ajw22]

Those are single speed pumps?

I think the 2HP pump for four jets gives too much water flow for the blower to overcome.

I have a 2HP spa jet pump and a 2HP air blower to eight jets that works well.

We have seen folks with your problem who have a VS pump turn down the pump flow until they find the right balance where the blower works with the water flow.

The air flow and water flow need to have a balance to merge properly at the venturi jet. Too much power in either over powers the jet and causes the types of problems you are seeing.