Blower Troubleshooting on Spa Jets

[alferz]

Hi all, I recently bought a home with a gunite pool/spa with a small spillway between the two. The pool is probably 1980’s vintage, but no one is quite sure how long its been there. One of the things Im trying to troubleshoot is the blower. It looks original and sounds like a jet engine, but the thing seems to be working fine. The spa its pumping air into is a half circle smaller spa. It has three wall jets, the center one seems to get most of the flow when the return valve is set to spa, but the other two get some water flow as well.

There are 6-10 floor bubblers and when the blower is on, a considerable amount of air comes out of them. The 3 wall jets dont have any air coming out of them however, just the return water pressure from the main filter pump. There is an upside down p-trap style air vent close to the blower, but nothing is coming into or out of this vent when the blower is on so Im not sure what its purpose is (see photo). The 3 spa jets are female threaded ports but dont currently have anything screwed into them. They have small orifices inside them and seem like some kind of venturi jet, but there are no venturi valves adjacent to the spa or anywhere at the pool pad. The spa is 15 or so feet from the equipment pad and no Hartford loop anywhere I can see. Most of the plumbing is completely encased under concrete. There is a small older sprinkler valve (see photo) an inch from the blower, but I am not sure what its purpose is either. Opening/closing the valve seems to do nothing whether the blower is on or off.

- How can I tell if the spa was designed to be a floor bubbler only or if there is supposed to be air coming out of the jets?

- Any things I can try to get the jets working if so?

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[mknauss]

I suspect you have two systems for the spa? Do you have two pumps that run for the spa? One would be for the system tied to the blower (likely the floor) and the other to the open P trap pipe, likely the wall jets. Those jets need venturi inserts to pull air in.

@mas985 might be best to assist you in sorting this out.

 

[mas985]

There are 6-10 floor bubblers and when the blower is on, a considerable amount of air comes out of them.
- How can I tell if the spa was designed to be a floor bubbler only or if there is supposed to be air coming out of the jets?

So does this mean that they stop bubbling when the blower is off? If so, I think that answers your question. Blowers can be used for many reasons but are necessary for floor bubblers.

There is an upside down p-trap style air vent close to the blower, but nothing is coming into or out of this vent when the blower is on so Im not sure what its purpose is (see photo).

Venturis can draw air in on their own as long as they have enough suction to clear the air line. But if you don't feel any suction with the pump on, then that pipe may have been abandoned or perhaps is clogged with debri.

Try putting a shop vac on the end of the open pipe to see if you draw any debris or water. This can let you know if it is connected to the spa.

 

[alferz]

Try putting a shop vac on the end of the open pipe to see if you draw any debris or water. This can let you know if it is connected to the spa.

Success! Thank you for that tip, I was able to draw water from the spa through the vent pipe, and blowing into the vent pipe with the shop vac I got plenty of air out of those 3 jets, so the line is open and clear. I think I just need 3 venturi attachments. I measured the inside threads at 1 3/4" and took the pic of the inside of the jet below. You can see the small air port at the top where air should be suctioned in when water is flowing out of them. Are the venturi nozzles universal, or does it depend on manufacturer?

 

[mas985]

They depend on the manufacturer. Not universal.

However, if you remove the nozzles with long socket wrench, you can flush the lines of remaining debris.

 

[alferz]

Thanks @mas985 for the tip, I used a 1/2" socket to remove the nozzle/orifice out of 1 jet and took out the part that looks like the photo below. The other two were very brittle and the hex actually broke so I drilled two holes in the PVC and turned them out with needlenose pliers. The orifice in the pic is 1" threaded with a 1/2" hex piece at the top, 1 5/8" long in total. The venturi jet attachment would screw into the wall ports with 1 3/4" threads. The attachment would go into the port about 2 1/8" total before hitting the orifice. I got a little debris out, couple of small rocks (no idea how they got in there). This pool is 1980's or possible older.

After much searching I have not been able to find the part in the picture below, or a replacement for the original venturi attachments which are long gone. Anybody have any tips on how I can figure out who made this jet system and how I can find the right parts to return it to working condition? Am I stuck with no air until I decide to rip up the pool deck and replace the whole system long in the future?

 

[mas985]

The important thing is to match the thread pitch and diameter. If you have those two values, you should be able to find something that will work.

Check with Inyo pool and they may be able to help.

 

[alferz]

Thanks again, will try Inyo. If worst comes to worst and I cant find the right fittings, what about plumbing my floor bubbler blower to the passive vent line for the wall jets and just blowing air to both sections at once? Any issues having both floor bubblers and wall jets on the same blower, do they have to be separate?

 

[mas985]

Without the nozzles, the jets are going to be useless. Very weak.

And yes, those are two very different functions so they may require separate blowers to work properly.