Home Purchase - Spa Pump / General Advice

[golfski]

I am under contract for a home with a pool and wanted to get some info before releasing contingencies. The pool has a spa with waterfall flow, but there is only a single VS pump that is serving as both the filter system and the spa jet pump. In my previous pool it had a jet pump for the spa bubbles and the VS pump for the filter flow. The jets were not very bubbly, they flowed and jetted water out, but the surface wasn't thrashing like I have had in previous pool. I have attached some pictures of the current pump and filter/switch setup. Would be curious if someone could given idea of what would be needed to add a jet pump or increase flow to get the desired spa effect. Is this a huge under taking or just more equipment and installation?

Other thing I noticed was that when the spa was on there was a vent pipe sticking out of the ground near by and it was making a rattling noise. Is there something I can do to fix that noise or reduce it or is it indicative of something? The home inspector said it was pulling in air for the system. Want to make sure it's fixable so to not have to always listen to that while relaxing in the hot tub. Here is a link to a vide of the noice I captured. filter_noise.MOV

Any information is appreciated!

 

[ajw22]

It is impractical to retrofit a dedicated spa jet pump into a single-pump spa system. Your pipe sizes are probably too small to increase flow much, and two pumps should not share the spa suction. Each pump should have its own suction from the spa.

If you buy the house you should plan on the spa being the way you see it until you do a major overhaul of it.

The spa has a venturi air line and not a spa blower. The air line should not be rattling like that. It may have dirt or rocks in the pipe. It is not clear from the video what it will take to get access down into the line to see what is making the noise.

 

[golfski]

It is impractical to retrofit a dedicated spa jet pump into a single-pump spa system. Your pipe sizes are probably too small to increase flow much, and two pumps should not share the spa suction. Each pump should have its own suction from the spa.

If you buy the house you should plan on the spa being the way you see it until you do a major overhaul of it.

The spa has a venturi air line and not a spa blower. The air line should not be rattling like that. It may have dirt or rocks in the pipe. It is not clear from the video what it will take to get access down into the line to see what is making the noise.

Thanks for the reply! What would be considered a major overhaul? We love the house and everything, just want the jets to be more powerful. Could the rocks/dirt or whatever is causing the rattling in the air line be causing the lack of power in the jets? It seems like it should be more powerful than it is.

 

[ajw22]

What would be considered a major overhaul?

Invasive surgery on the spa to install new drains on the side or floor of the spa and running pipe to the equipment pad.

Could the rocks/dirt or whatever is causing the rattling in the air line be causing the lack of power in the jets?

Nope.

The venturi air flow does not affect the spa jet water flow.

It seems like it should be more powerful than it is.

Your one pump has to run through the restrictions of the filter and heater, which slows down the flow.

Whereas a dedicated spa jet pump with large pipes has little resistance to the water flow.

Pump Basics - Further Reading

www.troublefreepool.com

Equipment Pad Best Practices - Further Reading

www.troublefreepool.com

 

[golfski]

Invasive surgery on the spa to install new drains on the side or floor of the spa and running pipe to the equipment pad.



Nope.

The venturi air flow does not affect the spa jet water flow.



Your one pump has to run through the restrictions of the filter and heater, which slows down the flow.

Whereas a dedicated spa jet pump with large pipes has little resistance to the water flow.

Pump Basics - Further Reading

www.troublefreepool.com

Equipment Pad Best Practices - Further Reading

www.troublefreepool.com

Thanks for all the replies. That is a bummer to hear, I am going to have to have a pool inspector or contractor check this thing out before moving forward, the spa is the main reason my wife wants the house. We are used to the dedicated jet pump and that experience and don't want a hot bath like experience, lol.

The equipment pad is on the other side of the house, probably 80-100ft away, so I can't imagine running drain lines would be that easy or cheap (or possible?) to add the dedicated line. The spa has three drains at the bottom, is that any indication of how everything is set up? I am just so surprised that someone would build a spa like this - so assume something is wrong.

 

[ajw22]

Are you sure that the VS pump was running at its maximum speed of 3450 RPM when the spa was on?

The pump display should display a GPM flow rate. It would be informative to know what GPM the pump is pushing at maximum RPM .

How many jets are in the spa?

Do you have better pictures of the suction side input to the pump?

Did you put your hand in the spa and feel the pressure of the jets?

 

[ajw22]

I don't know why you have 3 drain covers in your spa.

They are usually groups of two to prevent suction entrapment.

 

[golfski]

Are you sure that the VS pump was running at its maximum speed of 3450 RPM when the spa was on?

The pump was on its 3rd speed and was running at 2800, I tried to turn it to the 4th speed and it only went up to 3000 and didn't see much difference.

The pump display should display a GPM flow rate. It would be informative to know what GPM the pump is pushing at maximum RPM .

I will have to check this next time I am out there tomorrow.

How many jets are in the spa?

There looked to be 4 jets in the spa, will confirm with more pictures tomorrow.

Do you have better pictures of the suction side input to the pump?

Sorry for being dense, I am not 100% sure what you are talking about here? I am heading back tomorrow and can take as many pictures as possible

Did you put your hand in the spa and feel the pressure of the jets?

Admittedly I did not! The jets actually looked to be pushing water with some force. To be honest, I am not as worried about the force of the jets from a massage standpoint, more from a bubble standpoint and the overall experience of a thrashing hot tub on the surface (bubbles) with the hot water...worried it will be like a hot bath if its too calm. Ideally you can't see the bottom below the surface when on.

I have been reading up on the Venturi line and other threads on there and many folks mention that is how you control the amount of bubbles? In the video I shared above (image attached here) the Venturi pipe has a cover on it with only three little holes poked. I noticed others talking about a 'cane' shaped Venturi but also that if you open it up completely you get tons of bubbles? Could this be my issue and what I am missing? Again, will have to check the pressure of the jets tomorrow but it's the amount of bubbles and surface thrash that I am surprised about and wanting to increase.

 

[ajw22]

The suction pipes are behind the filter. I can barely see the suction valve actuator. And the pipes painted black do not help see the pipes.

Seeing what suction pipes there are from the pool and spa, that all come together at the pump, may answer the question on three spa drains.

Also post larger pictures so things can be zoomed in.

Picture Posting and Resizing - Further Reading

www.troublefreepool.com

 

[ajw22]

With a venturi air system the water velocity is what pulls the air through. So the greater the water flow, the more air will be pulled through.

The air can be gated by the size of the air pipe opening and once you own the house you may find opening the air pipe gives more bubbles. Or it may not.

 

[anomale]

Aside from a faster pump speed and pipe sizing, It could also be a dirty filter causing the lack of bubbles. You can look at the filter pressure to determine if it is dirty or not. We have the venturi pipe and ours makes a gurgling sound when the jets are on, It is sucking air into the lines, I think that sound is normal.

 

[golfski]

With a venturi air system the water velocity is what pulls the air through. So the greater the water flow, the more air will be pulled through.

The air can be gated by the size of the air pipe opening and once you own the house you may find opening the air pipe gives more bubbles. Or it may not.

Aside from a faster pump speed and pipe sizing, It could also be a dirty filter causing the lack of bubbles. You can look at the filter pressure to determine if it is dirty or not. We have the venturi pipe and ours makes a gurgling sound when the jets are on, It is sucking air into the lines, I think that sound is normal.

Little update here - went back out to the house today and they had the pool guy come yesterday and turn up the pump to max speed (3450 rpm), which seems to have made a pretty decent difference (see image below) in the amount of bubbles and thrash on the surface, where my wife and I are definitely relieved that we can get it to this point just by increasing pump speed. It also has lessoned the gurgle from the Venturi, seems like its pulling air much smoother at a higher speed - still will try to open it up a little to see if it produces even more bubbles.

Since there is only the 4 jets that are in the loop to heat the spa, will running at a higher speed make it take longer to heat to full temp (103-104)? Just want to make sure nothing else to consider now that we are running on the full speed to get the desired effect.

We also plan on replacing the filter, is there a specific filter (brand/model/type) we should look at to ensure best flow for pressure in the spa? Assuming a new clean filter will help things as well!

Definitely relieved that we are not going to lose the house over the spa!! Thanks everyone for all the details and help!

 

[PoolStored]

Since there is only the 4 jets that are in the loop to heat the spa, will running at a higher speed make it take longer to heat to full temp (103-104)? Just want to make sure nothing else to consider now that we are running on the full speed to get the desired effect.

Generally speaking, the faster the flow rate the more efficient the heat transfer, but the efficiency has to do with the temperature difference between the heat source and the fluid being heated so there are diminishing returns at faster and faster flow rates. The rate of heat transfer between two points is a function of the thermal conductivity of the material between the two points and the temperature difference between the two points (and the amount of area of contact). A faster flow rate means the temperature of the water doesn't rise as much so that makes the rate of heat transfer somewhat higher. I don't think you will have any appreciable difference in the heating based on flow rate. What gas heater do you have? (You only list "hayward gas heater"...what is the model of the heater?

We also plan on replacing the filter, is there a specific filter (brand/model/type) we should look at to ensure best flow for pressure in the spa? Assuming a new clean filter will help things as well!

Are you replacing the filter or the cartridges? If FILTER, get the largest cartridge filter you can find. If the CARTRIDGES, post the make/model of the existing filter. Not much real difference in cartridges.

 

[golfski]

Generally speaking, the faster the flow rate the more efficient the heat transfer, but the efficiency has to do with the temperature difference between the heat source and the fluid being heated so there are diminishing returns at faster and faster flow rates. The rate of heat transfer between two points is a function of the thermal conductivity of the material between the two points and the temperature difference between the two points (and the amount of area of contact). A faster flow rate means the temperature of the water doesn't rise as much so that makes the rate of heat transfer somewhat higher. I don't think you will have any appreciable difference in the heating based on flow rate. What gas heater do you have? (You only list "hayward gas heater"...what is the model of the heater?

Sorry, the Hayward heater was my old pool, this new house has a Pentair MasterTemp 400K -- new in the last two years, looks really good. It is a long run, I would say 80-100ft from the spa/pool to equipment pad (other side of house).

Are you replacing the filter or the cartridges? If FILTER, get the largest cartridge filter you can find. If the CARTRIDGES, post the make/model of the existing filter. Not much real difference in cartridges.

We are going to replace the whole filter, it seems pretty small compared to what I used to have at old pool and its very old. The pump (Pentair VSP Intelliflo) and Heater (Pentair MasterTemp 400K) are both new in last two years. The Hayward C2025 filter is pretty old and the Jandy AquaLogic is super old it looks like, so going to probably upgrade to Pentair filter and Automation/Controls. Reading up on the filter it looks like it has a Flow Rate of 77GPM, while the next size up (C3025) flows at 122 GPM. I assume that would create better pressure?