My spa jets have stopped putting out air bubbles

[gdo]

My spa doesn’t have a dedicated blower. Instead there seems to be an air intake pipe that emits gargling sounds when I set my system in spa mode. That pipe is near the pool equipment, which is about 30 feet from where the spa is.




When I turn on the spa mode, I hear the pump ramp up, and the valves are moving such that the flow is directed towards the spa. However, the flow seems very weak when I put my hands near any of the spa jets.
If I manually blow in the air pipe, I’m able to “unwedge” the system and bubbles start appearing, with jets coming in at what appears to be full force.

I’ve had 2 pool guys come and try to fix this problem, and they both disregarded my initial analysis and instead decided to follow their “standard debugging flow”, which consisted of first cleaning up the filters, then disassembling all jets to check for blockages… I mentioned to them that I could “prime the system” manually which made these 2 causes not very likely, but that did not change their mind, and about $1,000 later, I’m no better.

My hypothesis is that there is something wrong with the venturi tee that brings in air to mix with the flow of water. I don’t know where this tee is since the air pipe goes “underground” at the equipment area, so the tee could be right there, or somewhere along the way to the spa. I imagine it is close to the equipment because the alternative means the builder would have had to build a long air pipe towards the spa for the mixing to happen near the jets. I think what could be happening is that at rest, the water is coming back up the air pipe to level with the spa’s highest point, and when I turn on the flow, the venturi mixer is unable to flush that extra water from the air pipe for some reason.

I’ve thought about workarounds:
1) add a blower that does what I manually do - I’m reluctant to do that since it used to work 2 years ago without any extra equipment. I don’t like to complicate systems and would prefer to find the root cause.
2) add a check valve in the air pipe to prevent water from coming back up that pipe, so it’ll be easier for the venturi to “prime” the next time around, without having to flush a bunch of water out first

What is my next step? Should I dig down to follow the air pipe and figure out whether I hit the venturi mixer close-by? And if so, is there a test I can run to check whether it is clogged/defective?

Advice much appreciated!

Thanks in advance!

 

[mknauss]

So did the spa ever work without pushing air into the air inlet? =-=- Sorry - see you said it worked two years ago.

A couple items. Be sure the filter is clean. You need good water flow to the spa jets.

Is the air inlet covered in a screen? It is possible for debris/critters to get in there and plug them. You might take the jets out of the spa and then push water down the air inlet to flush it.

 

[gdo]

So did the spa ever work without pushing air into the air inlet? =-=- Sorry - see you said it worked two years ago.

Yes, it used to work, about 2 years ago.

A couple items. Be sure the filter is clean. You need good water flow to the spa jets.

Same problem happens after filters have been cleaned.
If there was a flow problem, I would assume I would not be able to "un-wedge" it by blowing in the air pipe? When I blow air into it, within about 20-30 seconds, the bubbles start appearing. At that point, I can stop blowing into that pipe, as it seems to have reached a steady state that is working.
That tells me that after an initial condition clears, the system is able to pull in the air normally, so I'm ruling out a clog or a flow/pressure problem. Please tell me if this reasoning is not sound.

Is the air inlet covered in a screen? It is possible for debris/critters to get in there and plug them. You might take the jets out of the spa and then push water down the air inlet to flush it.

The air inlet used to be a pipe that was straight up, with a cover that had some holes drilled into it. Because it didn't have the "umbrella" (reverse U) shape, it is possible that gravity got something into it: if unlucky, tree sap, bird poo, or some other debris. Now that it has been modified to look like the drawing I attached, gravity can't make things fall into it, but things can still crawl back into it somehow.

I'm not sure I understand what you mean by pushing water down the air inlet. You mean (a) run the spa water pump and simultaneously (b) force-feed water into the air pipe so only water gets combined into the venturi (instead of water and air), to somehow attempt to dislodge or flush some debris? Did I understand this correctly?

Thank you for your assistance!!!

 

[mknauss]

Did I understand this correctly?

Just trying something easy first. You first take the jets out of the spa. Have you done that before? Normally takes a 9/16" socket with long extension for most jet assemblies.
Once those are out, use a hose to push water from the air inlet out the jets. Just trying to be sure nothing is in there.

If the system was installed correctly, you do not need a check valve on the air line. A Hartford Loop would have been installed that would have kept water out of the air inlet line. Though it sounds like that may be the issue.

 

[gdo]

Just trying something easy first. You first take the jets out of the spa. Have you done that before? Normally takes a 9/16" socket with long extension for most jet assemblies.
Once those are out, use a hose to push water from the air inlet out the jets. Just trying to be sure nothing is in there.

One of the pool repair guys who came did this. He removed them all (he thought something could be wedged in it and clog the flow). He didn't find anything.
The other repair guy cleaned the filter. That didn't help either.

If the system was installed correctly, you do not need a check valve on the air line. A Hartford Loop would have been installed that would have kept water out of the air inlet line. Though it sounds like that may be the issue.

Isn't the Hartford Loop only necessary when you have a blower connected to the air line, to prevent water from reaching the air blower? In my case, the air line just pops out of the ground (as diagrammed), and there is no water coming out of it, so the level of water at rest as it equalizes is probably lower that the highest point in that umbrella shape. Still that could be some water that needs to be "flushed" through the venturi system before it actually starts pulling air in, and perhaps the process is just too slow to happen naturally, so it ends up happening when I manually blow into the pipe.
Once that threshold is crossed, the system works well, and I don't need to blow into the pipe anymore.

 

[mknauss]

You need a Hartford loop. If it worked before, you must have one. It is likely buried.

My system is exactly like yours. Except my air inlet is about 10 feet from the spa. The shorter that distance, the easier to initiate the air flow.

My next step would be to inspect the jets to be sure they are sealing such that the air is being pulled into the venturi correctly.

 

[gdo]

You need a Hartford loop. If it worked before, you must have one. It is likely buried.

My system is exactly like yours. Except my air inlet is about 10 feet from the spa. The shorter that distance, the easier to initiate the air flow.

My next step would be to inspect the jets to be sure they are sealing such that the air is being pulled into the venturi correctly.

I can't find any Hartford loop anywhere.

My hypothesis is that there isn't one because I can see water in the air pipe on the equipment side, and it seems to be level with the spa's highest level too.



If there was a HL near the spa, I think it would prevent the water from getting to the equipment side, as the water level would never reach high enough to flow towards the equipment (which is on the left side in the diagram).

Does what I'm saying make sense?

Perhaps the builder intended the HL to be what I see on the equipment side?
I can see water in that air pipe, and when I turn on the spa, that water recedes. To me that means the venturis are somewhat working, but my guess is that they aren't working well enough to pull and flush all the water on the spa side, where the air is supposed to go back up the pipe from the buried depth. When I manually blow, it flushes that water, and then the venturis don't have any issues keeping up.

I wish I could easily add a HL on the spa side, but it's a circular spa that spills over into the pool and everything is encased in masonry/tiles, and because it's a spillover design, no pipe within the circumference would be higher than the highest water level in the spa, so that HL would have to be somewhat away from the spa, in another spot of the yard that is higher.

So I'm looking for a workaround now. I know exactly where the water settles on the equipment side, and it's about a foot up from the ground, and about 1-2 feet down from the top of the pipe.
Is it a bad idea to just add a blower there, such as https://www.amazon.com/Air-Supply-Florida-Silencer-Horsepower/dp/B0037TSEUO for example? The water level won't ever reach it (nothing in the water body is higher than where the blower would sit).

Thoughts?

 

[JoyfulNoise]

The Hartford loop is likely buried in the wall of the spa. That's how almost all spa plumbing is constructed with an HL. It's just a loop of pipe above the water line to keep pool water from backing up into the air line. It's possible that debris could be in the air line and the restriction is causing enough resistance that the Venturi cannot start the air flow. With the open pipe straight up, you could have gotten a lot of rain water in the air line.

Try closing all the jets but one and see if it initiates on its own.

 

[gdo]

The Hartford loop is likely buried in the wall of the spa. That's how almost all spa plumbing is constructed with an HL. It's just a loop of pipe above the water line to keep pool water from backing up into the air line.

I don't think that's possible: it's a circular spa, with a spillover design where the water spills over the walls of the spa into the pool. That means that the walls of the spa are always lower than the spa's water line. That means that no plumbing within those walls can get above the water line.
I've looked in the vicinity of the spa as well (in the landscaping areas nearby) but can find no pipe sticking out.

I think that if there was a HL near the spa, I would not see water on the air intake pipe on the equipment side, as it would be blocked by the HL before being able to travel all the way back to where the equipment is.
Is this thinking incorrect?

Try closing all the jets but one and see if it initiates on its own.

None of my jets can be closed, I'm afraid. I can ask some assistance from family members to plug them with their hands as I'm running out of hands on my own.

 

[JoyfulNoise]

If your spa walls are raised, then the H/L can be buried in the wall somewhere even if it is a spillover spa. Perhaps if you post of picture we can see more clearly what you have.

In the case of a spa that is at pool level (no spillover), then a check valve will sometimes be used to keep water from backing up into the air line.

 

[1poolman1]

I can't find any Hartford loop anywhere.

My hypothesis is that there isn't one because I can see water in the air pipe on the equipment side, and it seems to be level with the spa's highest level too.

View attachment 487682

If there was a HL near the spa, I think it would prevent the water from getting to the equipment side, as the water level would never reach high enough to flow towards the equipment (which is on the left side in the diagram).

Does what I'm saying make sense?

Perhaps the builder intended the HL to be what I see on the equipment side?
I can see water in that air pipe, and when I turn on the spa, that water recedes. To me that means the venturis are somewhat working, but my guess is that they aren't working well enough to pull and flush all the water on the spa side, where the air is supposed to go back up the pipe from the buried depth. When I manually blow, it flushes that water, and then the venturis don't have any issues keeping up.

I wish I could easily add a HL on the spa side, but it's a circular spa that spills over into the pool and everything is encased in masonry/tiles, and because it's a spillover design, no pipe within the circumference would be higher than the highest water level in the spa, so that HL would have to be somewhat away from the spa, in another spot of the yard that is higher.

So I'm looking for a workaround now. I know exactly where the water settles on the equipment side, and it's about a foot up from the ground, and about 1-2 feet down from the top of the pipe.
Is it a bad idea to just add a blower there, such as https://www.amazon.com/Air-Supply-Florida-Silencer-Horsepower/dp/B0037TSEUO for example? The water level won't ever reach it (nothing in the water body is higher than where the blower would sit).

Thoughts?

I don't think that's possible: it's a circular spa, with a spillover design where the water spills over the walls of the spa into the pool. That means that the walls of the spa are always lower than the spa's water line. That means that no plumbing within those walls can get above the water line.
I've looked in the vicinity of the spa as well (in the landscaping areas nearby) but can find no pipe sticking out.

I think that if there was a HL near the spa, I would not see water on the air intake pipe on the equipment side, as it would be blocked by the HL before being able to travel all the way back to where the equipment is.
Is this thinking incorrect?



None of my jets can be closed, I'm afraid. I can ask some assistance from family members to plug them with their hands as I'm running out of hands on my own.

Don't plug them with your or their hand. That will only force water into the airline. Air and water mix right at each jet. While a Hartford loop may be the preferred way to plumb, my 40+ year old pool doesn't have one and the jets work just fine. Water will always flood the airline with the spa off. It takes a certain amount of flow to create the venturi effect needed to clear it. Are the jet orifices worn out/damaged. Even a slightly damaged orifice can disrupt the flow enough that the waterflow can't clear the air line. Can you drain the spa into the pool far enough below the jets to actually see the water coming out of them. It should be in a straight, almost laminar, stream. If even one is not, it can be forcing water into the airline and it takes that extra push from you, especially at 30', to get the line cleared. Then, they work until the next time.

That issue is usually caused by a waterflow problem. Just because the filter has been recently cleaned does not mean that full flow has been restored. Is this a cartridge filter? How old are the cartridges? They/it could be worn out. Have you tried taking a/the cartridge out of the tank and running the system? If it is DE, just remove the cluster and try. If the bubbles are restored you've found the problem. If not, adding an air blower certainly won't hurt.

Be sure to not oversize it thinking "bigger is better." Bigger will just burn up if there are not enough jets to accept all the airflow. All blowers come with a check valve of some sort, not to prevent water from entering the line, but to prevent the reverse surge of water from entering the blower. If you add a blower, they DO NOT get glued to the pipe. Some come with a "set-screw" some with a recommendation of how to prevent the blower from coming off the pipe.

 

[gdo]

If your spa walls are raised, then the H/L can be buried in the wall somewhere even if it is a spillover spa. Perhaps if you post of picture we can see more clearly what you have.

In the case of a spa that is at pool level (no spillover), then a check valve will sometimes be used to keep water from backing up into the air line.

Here's a picture of the (raised) spa:



I'm really surprised by your statement that a HL could be buried in the wall even if it's a spillover spa: I don't understand the physics that would prevent the loop from being flooded, since the loop would be lower than the highest level of water in the spa.

I admit I'm not the strongest in fluid dynamics, but I really thought that the HL had to be higher than the highest point in the spa. This explains it better than I could: Pool Patrol - The Pool and Spa Professionals

There's obviously something I'm missing in understanding how HLs work... What am I misunderstanding?

 

[1poolman1]

Here's a picture of the (raised) spa:

View attachment 487718

I'm really surprised by your statement that a HL could be buried in the wall even if it's a spillover spa: I don't understand the physics that would prevent the loop from being flooded, since the loop would be lower than the highest level of water in the spa.

I admit I'm not the strongest in fluid dynamics, but I really thought that the HL had to be higher than the highest point in the spa. This explains it better than I could: Pool Patrol - The Pool and Spa Professionals

There's obviously something I'm missing in understanding how HLs work... What am I misunderstanding?

Hartford loop MUST be above water level to work or it is just a bunch of extra pipe and fittings. And, it would have to be high enough that the back surge of water that would occur when the system shuts down would not be able to go over the top of the loop. So, it would have to be above ground in your case. There is none in that wall.
From a much earlier post:

Spa Blower Piping

When the plumbers set the equipment pad, they roughed the 2 inch PVC line that the spa blower line is attached to right in front of a kitchen window. I have a ton of space to reroute, but before I cut the line below ground to replumb I am curious if it is full of water or strictly an air line? I...

www.troublefreepool.com

 

[JoyfulNoise]

Here's a picture of the (raised) spa:

View attachment 487718

I'm really surprised by your statement that a HL could be buried in the wall even if it's a spillover spa: I don't understand the physics that would prevent the loop from being flooded, since the loop would be lower than the highest level of water in the spa.

I admit I'm not the strongest in fluid dynamics, but I really thought that the HL had to be higher than the highest point in the spa. This explains it better than I could: Pool Patrol - The Pool and Spa Professionals

There's obviously something I'm missing in understanding how HLs work... What am I misunderstanding?

Ah, I see your spa configuration now. From your original descriptionI couldn’t tell how far around the spill over went.

Do you have any photos from when the pool was constructed specifically showing the plumbing in the spa before the shotcrete work was done? That would be helpful in understanding your issues. Pool plumbers and builder can do all sorts of funny things and often times you don’t realize it until after they’ve collected their last check and are long gone, sadly.

Perhaps there’s a check valve in the air line somewhere that’s failing?

 

[gdo]

Don't plug them with your or their hand. That will only force water into the airline. Air and water mix right at each jet. While a Hartford loop may be the preferred way to plumb, my 40+ year old pool doesn't have one and the jets work just fine. Water will always flood the airline with the spa off.

I think this is what is happening to me. Once I "prime" the bubbles manually, it works, and then when I stop the spa pump, the water comes back up the air pipe near the equipment. I thought that meant there was neither a check valve or a HL near the spa.

It takes a certain amount of flow to create the venturi effect needed to clear it. Are the jet orifices worn out/damaged. Even a slightly damaged orifice can disrupt the flow enough that the waterflow can't clear the air line.

I haven't checked them personally. One of the pool techs who came disassembled all the jets to check for obstructions and I assume he took a look at them for signs of damage, but I'm not 100% sure.

Can you drain the spa into the pool far enough below the jets to actually see the water coming out of them. It should be in a straight, almost laminar, stream. If even one is not, it can be forcing water into the airline and it takes that extra push from you, especially at 30', to get the line cleared. Then, they work until the next time.

Yes, I guess I could run that experiment.

That issue is usually caused by a waterflow problem. Just because the filter has been recently cleaned does not mean that full flow has been restored. Is this a cartridge filter? How old are the cartridges? They/it could be worn out. Have you tried taking a/the cartridge out of the tank and running the system? If it is DE, just remove the cluster and try. If the bubbles are restored you've found the problem. If not, adding an air blower certainly won't hurt.

It's a cartridge filter (4 cartridges) and they have been cleaned recently by my pool guy. I asked him if they needed replacement and he said they were in good shape. I don't read any high pressure on the filter, so I'm assuming the flow is reasonably good. When I start the spa mode, I can clearly see the water receding down in the air pipe, and it really gets pulled fast: it's not struggling to disappear from the vertical segment where I stand. I just can't tell what happens after that first bend.

It seems to me that adding a blower is an easy (and relatively cheap) solution that will build some level of tolerance against "imperfect flow conditions". Is there a downside to it (I mean, other than having to install it, the electrical cost, and the noise)?

Be sure to not oversize it thinking "bigger is better." Bigger will just burn up if there are not enough jets to accept all the airflow. All blowers come with a check valve of some sort, not to prevent water from entering the line, but to prevent the reverse surge of water from entering the blower. If you add a blower, they DO NOT get glued to the pipe. Some come with a "set-screw" some with a recommendation of how to prevent the blower from coming off the pipe.

This might be the simplest solution. The blower at https://www.amazon.com/Air-Supply-Florida-Silencer-Horsepower/dp/B0037TSEUO should sit nicely on top of the air pipe, and when the pump turns off and the water comes back up that air pipe, there would still be one to two feet of air before water can even reach the check valve, simply due to the elevation at the top of the air pipe.

 

[gdo]

Ah, I see your spa configuration now. From your original descriptionI couldn’t tell how far around the spill over went.

Oh I think I see what you mean now: there are circular designs where the water level is lower that the topmost area, for example when there are notches for the water to spill through. In that case, it is possible to have some in-wall plumbing that is above the water line indeed. Thank you for sticking with me on this!

Do you have any photos from when the pool was constructed specifically showing the plumbing in the spa before the shotcrete work was done? That would be helpful in understanding your issues. Pool plumbers and builder can do all sorts of funny things and often times you don’t realize it until after they’ve collected their last check and are long gone, sadly.

Unfortunately, no. It was like this when I bought the house. I did get the plans from the city, but I remember going through them a while back and saw designs that ended up not being implemented, so it's a mix of "we wanted to do this, but scratch that, we ended up doing that instead", so I don't really know what I can trust from that.
I know this was remodeled not too long ago, and the spa was added to an existing pool (which was also modified during the remodel), so the spa is relatively recent (~5 years?).

Perhaps there’s a check valve in the air line somewhere that’s failing?

Would that check valve be buried/in-wall or would it be accessible for maintenance? There's no plumbing visible anywhere near the pool/spa: it all comes out on the other side with the equipment. There, there are quite a few check valves, but none in line with the air pipe.

 

[JoyfulNoise]

I know this was remodeled not too long ago, and the spa was added to an existing pool (which was also modified during the remodel), so the spa is relatively recent (~5 years?).


Would that check valve be buried/in-wall or would it be accessible for maintenance? There's no plumbing visible anywhere near the pool/spa: it all comes out on the other side with the equipment. There, there are quite a few check valves, but none in line with the air pipe.

Oh. Ok. That is a significant detail. So this spa was added to an already existing pool. That means the pool remodeler would have had to plumb the spa separately from any existing pool plumbing.

A check valve could be anywhere on the air line but, since you’ve said this was an addition, it makes more sense that they would just do the easiest thing which would be to have a flooded air line as opposed to trying to come up with a way of keeping the water out.

A flooded air line definitely makes it harder for the jets to get going on their own. There may not be enough suction force to clear the line. I think if that’s the case, then a blower is your only real option.

 

[gdo]

Oh. Ok. That is a significant detail. So this spa was added to an already existing pool. That means the pool remodeler would have had to plumb the spa separately from any existing pool plumbing.

A check valve could be anywhere on the air line but, since you’ve said this was an addition, it makes more sense that they would just do the easiest thing which would be to have a flooded air line as opposed to trying to come up with a way of keeping the water out.

A flooded air line definitely makes it harder for the jets to get going on their own. There may not be enough suction force to clear the line. I think if that’s the case, then a blower is your only real option.

Sounds good. I ordered one online. Should be here Friday. Will let you know how it goes!
Thanks again!

 

[gdo]

It got here a day early, so I just gave it a shot, and it works! The bubbles appear within just a few seconds of turning the blower on!

Will post more info at Easytouch 8 programming: Turning on the blower when in Spa mode