Spa Blower too Powerful?

[WetSteve]

New pool and they installed a 220 V 1.5 HP 4.5 A 60 Cycle 120 CFM Silencer Air Blower for the spa/hot tub. Line is 2" and the six inlets in the spa are 1".

Problem is that the air pressure is so strong the water bubbles over the top of the spa when it is turned on. I replaced the 1" with 1/2" inlets and the effect was much, much better but the blower motor shut down so that's not a solution.

How can I reduce the air pressure of the blower motor? I though about installing an adjustable valve on the air line but thought the experts here have probably encountered this before and can offer some sage advice

Thanks in advance, Steve

 

[chiefwej]

I have a jandy three way valve on my air line. That allows me to adjust how much air gets mixed in at the spa jets. I see no reason you couldn't do the same. Just to be clear, a three way allows you to divert some of the air flow, do not block or restrict it, so as to not cause the blower to shut down.

 

[WetSteve]

Thanks for the quick response. I don't think I can use a Jandy valve because the air is mixed at the spa. I'm thinking I need a way to release some pressure near the blower motor. Here's a picture of how they built the spa...View attachment 66435

 

[chiefwej]

Where is the blower? The valve can be installed right below it.

 

[Mayorb]

Your blower is the correct size for 6 jets. I believe it is better to relieve pressure than to restrict flow, as added restriction will put undo strain on the blower and shorten its life. I have seen this issue resolved by cutting thin slits in the PVC pipe beneath the blower. Use a hacksaw and make the slits one by one while the blower is running, until desired pressure is reached. Drilling small holes would work also.

 

[buckweet1980]

Are there speed controls for these blower fans that one could get? While I like the idea of using a pressure relief vavle, it still doesn't change the fact how noisy these motors are..

 

[mas985]

Have you ever tried running without the blower (removed from air pipe)? A well designed spa does not require a blower.

 

[chiefwej]

Just to be clear, the Jandy three way valve I suggested should be installed so that it never restricts the air flow from the blower, but only diverts a portion to outside air. So it's affect is to release part of the air pressure right below the blower. It has the added advantage of being adjustable.

 

[WetSteve]

Have you ever tried running without the blower (removed from air pipe)? A well designed spa does not require a blower.

Are you saying a well designed spa doesn't need a blower (air), just water jets?

- - - Updated - - -

Just to be clear, the Jandy three way valve I suggested should be installed so that it never restricts the air flow from the blower, but only diverts a portion to outside air. So it's affect is to release part of the air pressure right below the blower. It has the added advantage of being adjustable.

Thanks, yes, by using smaller inlets I already found the blower motor will shut off so the only way I see is to relieve air pressure. The Jandy seems like overkill though

 

[mknauss]

Are you saying a well designed spa doesn't need a blower (air), just water jets?

That is right. You need an air inlet relatively close to the spa. And you need the plumbing done so it will work. Mine is that way. It bubbles, but not crazy.


Take care.

 

[tstex]

Although the solution of cutting or drilling holes in the PVC next to blower does sound practical, I would refrain from this since you/we are from Texas. Insects can climb into any hole/cut/etc, and would not want insects or the like being blown into my spa. You could do the above and then wrap with a fine screen, but this would lessen your air loss and look kind of "cheesy" maybe.

Although the jandy valve might be overkill, it would surely look the best and allow you a mechanism for adjusting the airflow..w the drilled holes, it's only an option for less pressure and not reversible, unless you get PVC couplings.

Finally, since your pool is new, I would go back to the PB and ask them to resize your blower. What they did was unacceptable and should have been tested. this to me is the best option, requires no retrofitting to your PVC infrastructure would also look the best too...good luck, tstex

 

[mas985]

Are you saying a well designed spa doesn't need a blower (air), just water jets?

Yes! Spa jets use venturis which pull in air all by themselves. I have a spa with just an air line and get plenty of bubbles. So much that they will also bubble on to the deck. Really, the only reason to use a blower is to clear the air line of water because of a bad design (IMHO). If a PB puts in a Hartford loop close to the spa, which most don't, the air line does not fill with water so it is much easier to clear. I know of well designed spas that have over 100' of air line but still do not require a blower and they get plenty of bubbles.

 

[chiefwej]

My spa has no blower, but I still have a jandy three way on the air supply line. It allows me to turn off any air to the spa jets while I'm preheating the spa. As far as the need for a blower, there are four pools on my block, all designed and built by the very same builder. All but mine have a blower. I always thought that the reason my spa didn't need a blower was that it is placed at the same water level as the pool vs all the others which are raised spas. The air intake is located 60 feet away from the spa, at my equipment pad. I probably don't get quite as much aeration on the jets as those with a blower. But it works fine.