Question about adding a Air Blower

[mas985]

Upload the video to youtube and then post the link. But I don't think that will matter. You should only see water in the pump basket. Any air, and you have leak.

 

[Gupone]

Upload the video to youtube and then post the link. But I don't think that will matter. You should only see water in the pump basket. Any air, and you have leak.

The pump itself is not reliable. I really couldn't tell you what the shape of this thing is in. Its old, may not have a good impeller and could be sucking air from someplace. With that said, I'm thinking about getting a new pump. I would like a recommendation on the HP, type and possible brand. I would like this pump to work with my current situation as mentioned in all of this thread but also would be good to use at the point when I am able to re-plumb the spa properly. Any help would be great.

 

[mas985]

First, we need to establish the flow rate requirements of the jets. I showed you documentation which stats that 20 GPM is required for each jet. You then responded that you still thought the jets required 10 GPM but did not provide any source for that information. However, the test you did confirms that the jets you have are 20 GPM jets. I estimate that with 8 jets, you have about 12 GPM/jet. Removing and capping 4 jets, results in a flow rate of 21 GPM/jet which to you felt strong.

So, if the jets are indeed 20 GPM, there is no way you are going to get that kind of flow rate from a residential pool pump on 2" plumbing. With those jets, the PB should have plumbed two loops with separate pumps. You would need to go with an extremely large industrial pump to get that kind of flow rate with a single loop but it would not be recommended to even try.

If the jets are 10 GPM, the pump you have now should be working fine but it is not. So I suspect that the jets are not 10 GPM but are 20 GPM. If you can actually find 10 GPM jets, you may be able to get the system to work properly.

BTW, if there is any doubt about the impeller performance, remove the motor from the wet end and inspect the impeller. It is fairly easy to do.

 

[Gupone]

First, we need to establish the flow rate requirements of the jets. I showed you documentation which stats that 20 GPM is required for each jet. You then responded that you still thought the jets required 10 GPM but did not provide any source for that information. However, the test you did confirms that the jets you have are 20 GPM jets. I estimate that with 8 jets, you have about 12 GPM/jet. Removing and capping 4 jets, results in a flow rate of 21 GPM/jet which to you felt strong.

So, if the jets are indeed 20 GPM, there is no way you are going to get that kind of flow rate from a residential pool pump on 2" plumbing. With those jets, the PB should have plumbed two loops with separate pumps. You would need to go with an extremely large industrial pump to get that kind of flow rate with a single loop but it would not be recommended to even try.

If the jets are 10 GPM, the pump you have now should be working fine but it is not. So I suspect that the jets are not 10 GPM but are 20 GPM. If you can actually find 10 GPM jets, you may be able to get the system to work properly.

BTW, if there is any doubt about the impeller performance, remove the motor from the wet end and inspect the impeller. It is fairly easy to do.

mas985, As always, thanks for your honest and expert information. I was basing the 10-13 GPM for each jet on the average flow that the spec sheet was talking about. They were saying if you want a more Therapeutic type pressure then you would want around 20 GPM. I know I'm not going to get that high even if there was a venturi type setup. I know a 2-3 HP high pressure / High Head pump would be the best I could go with the current 2" pluming on the suction and return lines. When I tested how much pressure I would feel if I blocked off Jets, I did not actually have the Jet insert in the housing. The housing has an opening of around 1" (see Pic) and what I am going to do is replace the insert That the PB had (see pic) with a single hole type (See Pic) which should give even more pressure. Like I said, I would be happy, not super excited to block of a couple Jets and get the kind of pressure I did during my testing. As for the pump, I can't even get the housing clamp off to be able to separate the wet end and see what the impeller condition is in. I am going to provide a YouTube link that hopefully will work so you can see how the pump is working. I understand that you do not want any air in the pump but I don't see any leaks anywhere above ground. I just was trying to figure out what could be causing this type of turbulence. By the way, when I had the other pump on the system, it did not make the kind of "Tornado" like turbulence.

 

[mas985]

You have to set the video for public viewing.

If you went with a pump similar to the Whisperflo WFE-12 AND closed off 2 jets, you would be getting close to 19 GPM which should feel close to the same as when you closed off 4 jets with the other pump (i.e. 6x19 GPM vs 4x21 GPM). So basically, by upsizing to a 3 HP full rated pump, you can add 2 jets to the 4 jets that worked with a 2 HP up rated pump.

BTW, I think Therapeutic type pressure is what you want. That is a strong jet. 10 GPM, as you have felt, is a very weak jet.

 

[mguzzy]

I've been following this thread along. ... I've had pumps that have gotten so you can't open them up.. I'll either replace them or realize that if something else goes on it, its "new pump & motor time"
So yeah.. it appears these jets are designed to work at 20GPM only... I poked around to see if they had a different nozzles that would support 10 GPM, but it appears not... so given all the constraints you have I like @mas985 's suggestion for a work around. That way you'll get the therapeutic effect of the water jets as they were intended.. I remember how terrible the spa flow was when my old filter system started getting clogged. And you'll have to be fine with just bubbles on your feet. ?

 

[Gupone]

You have to set the video for public viewing.

If you went with a pump similar to the Whisperflo WFE-12 AND closed off 2 jets, you would be getting close to 19 GPM which should feel close to the same as when you closed off 4 jets with the other pump (i.e. 6x19 GPM vs 4x21 GPM). So basically, by upsizing to a 3 HP full rated pump, you can add 2 jets to the 4 jets that worked with a 2 HP up rated pump.

BTW, I think Therapeutic type pressure is what you want. That is a strong jet. 10 GPM, as you have felt, is a very weak jet.

Sorry about that. try the original video link.

Thanks again for your recommendation.

 

[mas985]

Sounds like the pump is cavitating. Also, the bubble is indicative of a suction side air leak. Both are symptoms of suction head loss being too high relative to return head loss (i.e. wrong pipe size and jet selection). Another reason to reduce the number of jets.

 

[Gupone]

Sounds like the pump is cavitating. Also, the bubble is indicative of a suction side air leak. Both are symptoms of suction head loss being too high relative to return head loss (i.e. wrong pipe size and jet selection). Another reason to reduce the number of jets.

Sorry, not a big expert on all the Head Loss stuff but what you are saying is you are thinking that on the suction line, I am getting air coming in at either the pump or possibly the pipes?

 

[mas985]

The most likely place to have an air leak is the pump lid gasket and/or the drain plug gaskets. Pool lube should fix that.

 

[Gupone]

The most likely place to have an air leak is the pump lid gasket and/or the drain plug gaskets. Pool lube should fix that.

I lubed the lid gasket last night, I will try the drain plug next. Do you think that the Impeller can cause any of this?

 

[mas985]

I doubt it. It is very difficult to damage an impeller but like I said before, you can remove the motor from the wet end to the inspect the impeller.

But I think the pump is actually working ok despite the air leak and cavitation. Neither affects performance much unless it gets very severe but the air leak in video is not too bad.

 

[mguzzy]

Sounds like the pump is cavitating. Also, the bubble is indicative of a suction side air leak. Both are symptoms of suction head loss being too high relative to return head loss (i.e. wrong pipe size and jet selection). Another reason to reduce the number of jets.

Gupy.. did you have any jets plugged when you did the video? Try plugging some jets (2, the 3, then 4...) and see if the cavitation changes..