Dimmer for 1hp 220v spa blower?

[jb]

Any body have a suggestion?

1st world problem, but my spa blower is too powerful. Its only 1HP which is the smallest one the manufacturer makes. But the bubbles splash over the side of the spa and its hard to talk in there, kind of like the news guy covering the incoming hurricane.

I figured my options are;
-find a dimmer switch that could handle this load. Its not that many amps since it is 220v like maybe 4 I can look it up. Its in a shed, so protected from the elements
-drill holes in the 2" pvc pipe below the motor to let air escape before hottub
-add an additional valve to the air return to the hot tub with same purpose as above to bleed of air, would be more adjustable than drilling holes
-try to locate a different manufacturer blower of less than 1 hp

Thanks in advance for any suggestions -

 

[Jimrahbe]

jb,

I don't think you can change the speed of a single speed motor by using a "dimmer" like you can with a light. If you could, all pumps would be variable speed pumps..

I don't have a gunite spa, so let's see what our other members have to say about how to fix your problem. I suspect that adding a valve to choke off the output side of the pump would be best, but I don't know that for sure..

Thanks,

Jim R.

 

[jseyfert3]

Dimmers are for non inductive loads, or very low inductance loads. A motor is a highly inductive load. There isn't a dimmer in the world that will handle that.

A variable frequency drive, or VFD, is used to control motor speeds. The motor has to be rated for use with a VFD, and I would be shocked if a spa motor was rated for VFD usage.

I suspect you will need a new motor or do something with the air.

 

[ajw22]

I suspect that adding a valve to choke off the output side of the pump would be best, but I don't know that for sure..

Venting off excess air before it gets to the spa is the way to reduce the spa air. Choking off the output side of a blower will overheat it.

The blower works at a fixed output. You then need to manage that volume of air produced. A high volume air vent can get noisy. PVC is inexpensive and it can take some experimentation to find the best setup for an environment.

 

[Bama Rambler]

While it's technically possible to run a single phase induction motor on a VFD, it potentially creates more problems than it's worth. The best method if you want a vfd is to replace the motor with a 3-phase motor and run it with the vfd. You'd be surprised at some of the configurations 3-phase motors come in.

If the motor itself isn't too loud for you, the easiest way to control the air flow is to install a 3-way valve in the discharge of the blower and use that to adjust the air flow to the spa. If the air is too noisy coming out of the valve you can get a pneumatic air muffler for about $25.

 

[jb]

Thanks guys sounds like installing a 3 way valve and perhaps an air muffler might do the trick. The equipment is in a shed so the noise isn't too bad as is.

My previous house had a hottub but no blower. It used a venturi design where the water would just suck some air into the system. At first, I thought it was a bit of a hokey setup , but looking back it made a relaxing amount of bubbles. With no noise.

 

[JJ_Tex]

Is this a new spa, and if so, have you asked your builder? It sounds like there may be more air coming out of your jets than water, which can cause it to be messy. They can adjust your jets to allow less back pressure/more water out. Can you also try upping the pump speed when in spa mode to push more water out and have a better water/air balance?

 

[mknauss]

Will your current system do the same? Properly designed spa systems should work without a blower. Have you tried removing it and see what the system is like?

 

[JJ_Tex]

As mknauss said, how is your spa without a blower? Mine is running right now (freeze protection mode) and has a good mix of air/water without the blower (see pic below). If I want more bubbled, I turn on the blower, but even then it shouldnt be too messy if tuned correctly.

 

[jb]

Will your current system do the same? Properly designed spa systems should work without a blower. Have you tried removing it and see what the system is like?

Unfortunately not. I just removed the blower and there is no change in spa mode

As mknauss said, how is your spa without a blower? Mine is running right now (freeze protection mode) and has a good mix of air/water without the blower (see pic below). If I want more bubbled, I turn on the blower, but even then it shouldnt be too messy if tuned correctly.

I didn't get that many bubbles in spa mode. Thats close but I'd like some more bubbles than that. Thanks for posting the pic. My freeze guard came on this morning also. By the way , in freeze mode your water should be returning to the pool also? Could you post another pic in spa mode with no blower? Seems you should have even more bubbles than that pic, no?

 

[JJ_Tex]

I didn't get that many bubbles in spa mode. Thats close but I'd like some more bubbles than that. Thanks for posting the pic. My freeze guard came on this morning also. By the way , in freeze mode your water should be returning to the pool also? Could you post another pic in spa mode with no blower? Seems you should have even more bubbles than that pic, no?

The above pic was in spa mode only, no blower and at low (1600 rpms). Below is with the blower, much more bubbles but not messy like you described (or mine before the PB adjusted the backflow of the jets). I will typically use the spa in spa only mode (at 2600 rpms for more bubbles than the pic above) since it is easier to talk and/or hear the TV, but I will turn on the blower (jandy 1.5 hp) at times if I want more bubbles.

Also, my freeze guard alternates between pool mode and spa mode.

 

[jb]

Here is my hot tub with blower 'on'

 

[JJ_Tex]

It looks like the bubbles are going straight up from the jets (and splashing on the coping) rather than being pushed out through the jet and then up. Do you have a variable speed pump, and can you try upping the RPMs to see if that helps?

 

[jb]

I do have a variable speed pump. I have not tried that. I will investigate and report back. I mostly just use the phone ap, I think I need to go to the web version to access that function I remember seeing it

 

[jb]

ok my spa mode default pump setting is 2750 and I get no bubbles without blower on. i am envious you get some real bubbles with spa only ( no blower) I notice your spa is ground level. Mine is raised 24" I wonder if that is playing into it.

My pool mode the pump is 3450 I can up the spa mode to that and see what happens, But I think that is a lot of power for only the spa.

Life is hard. The quest for the perfect amount of spa bubbles must go on

 

[AusPhil]

Dimmers are for non inductive loads, or very low inductance loads. A motor is a highly inductive load. There isn't a dimmer in the world that will handle that.

Technically there is not a common "light dimmer" that will handle an inductive load, however i have in my own garage over here in Aus an Inductive Motor speed controller rated at 1.5Kw(2hp) that is a simple rotary pot just like a dimmer.
Typically these get used on 240v tools using inductive motors as speed control when you don't need full speed.
I also have some commercial light dimmers that will handle up to 2400w transformers driving stage lighting, i know a transformer is not a single speed moter but it is a nasty inductive load to a digital dimmer

 

[Jimrahbe]

jb,

Running a VS pump at 3450 just does not make any sense at all.. unless you are in the Spa mode and want a lot of water flow..

I run my pool at 1200 RPM...

What is it that makes you run your pool at full speed???

Thanks,

Jim R.

 

[jb]

Technically there is not a common "light dimmer" that will handle an inductive load, however i have in my own garage over here in Aus an Inductive Motor speed controller rated at 1.5Kw(2hp) that is a simple rotary pot just like a dimmer.
Typically these get used on 240v tools using inductive motors as speed control when you don't need full speed.
I also have some commercial light dimmers that will handle up to 2400w transformers driving stage lighting, i know a transformer is not a single speed moter but it is a nasty inductive load to a digital dimmer

Thats interesting. I did see a few 220v high wattage dimmers and wondered. Many ran them on fans. Thought about trying one and monitoring it temp wise.

jb,

Running a VS pump at 3450 just does not make any sense at all.. unless you are in the Spa mode and want a lot of water flow..

I run my pool at 1200 RPM...

What is it that makes you run your pool at full speed???

Thanks,

Jim R.

HI Jim. its sep to the spa, but what makes it not make sense? I have 45k gallons its a lot of water to cycle no?

 

[mknauss]

I have 45k gallons its a lot of water to cycle no?

'Turnover' is a myth. See Determine Pump Run Time - Trouble Free Pool

You run the pump to generate chlorine (if you have a SWCG), distribute the chemicals you add each day, and skim the surface.
Chemistry keeps the water clear. The pump just moves stuff that falls into the pool to the filter.

 

[Jimrahbe]

JB,

The whole point of having a VS pump is to save on the electrical bill.. Even running 24/7, my pump costs less than $20 bucks a month. If you are running full speed, you may as well have a single speed pump.

As Marty points out, having to "turnover" your water X times a day is just a myth.

I have a SWCG, so I tend to run a long time at 1200 RPM to generate the chlorine I need. During this time my pool gets skimmed well and I have plenty of circulation.

How long do you generally run your pool at 3450 each day?

How are you chlorinating your pool? Tablets, SWCG or Liquid Chlorine? If tablets or SWCG, you will need to run fast enough to make the system work.. Each pool is different of course, so you will have to determine what works best for you.

I suggest that you try running your pump at 3000 or above for your spa and see if your jets and bubbles don't work better.

Thanks,

Jim R.