Help with New MaxFlo VS Pump

[TNova]

I figured I'd go to the best source I know for help....
I just installed a Hayward Max-Flo VS Pump (1.65 hp) and have run into a head scratcher for me. When running at it's highest speed (3,250 rpm), the pressure on my filter is about 18, when it drops down to speed 2 (1,750 rpm) the pressure is basically zero. This is a stark contrast from the 24 - 30 that it typically ran at with the 1.5hp single speed pump I just replaced. I also noticed that at both speeds the water is not circulating in the pool very well albeit much better at speed 4 (3250 rpm) and closer to what I was used to with the old pump (which completely died btw hence the replacement).

Since I was stumped, I decided to double check everything, I ended up taking apart the filter and completely cleaned the grids so that there was no assumed blockage. After getting everything back up and running there was no difference in the pressures at the different speeds. When I check the skimmer suction, there was plenty that I felt (although I never checked that by hand before so I can't really compare to the old single speed pump). I'm wondering if anyone has had any experience with this? My biggest concern is that i didn't buy the correct pump for my sized pool. The other thought is that the filter is undersized? Not really sure about anything at this point. Any and all help is greatly appreciated!!!

 

[mknauss]

What is your concern? A filter pressure of zero (I suspect that is not true, just that the gauge is probably a 0-60 psi and cannot measure 1-2 psi) is not a bad thing. You say there is water flow. Your single speed pumped similar to full speed on the VS pump. At half speed on your VS, you are pumping half the water flow. There is nothing wrong with that. The primary function of the pump is to skim the surface of the pool. Is that happening?

 

[TNova]

Thanks for the reply...

Right now, the water isn't moving enough to get any of the surface debris into the skimmer. This is at full power as well. My new problem is that the display on the User Interface is illuminated but is no longer displaying any words. I'm looking to try and find a solution or understand why this might have happened.

 

[mknauss]

That is a concern. The pump at full speed should be putting out as much flow as your old single speed.

Not sure about the display.

Was this a DIY install?

 

[TNova]

Yes, this was a DIY install but it was done with a friend who is an electrician and does some plumbing on the side (although not with pools).

The display was working fine and then just went blank. The pump is still working as it had before the display went. In my searches, I haven't found anyone with the same problem yet. I'm going to continue searching... I'm wondering if there is a chance that I just got a lemon. (?)

 

[TNova]

Figured I'd update with a few more steps. The pump seems to be working albeit not as I expect it should. The water is only circulating on top slightly and only when the pump is on speed 4 (3250 RMPs). Anything less and you wouldn't know that the pump is even on. In regards to the display, it has now reverted to showing scrambled ASCII characters. I have called Hayward and the local Hayward service provider will be coming over tomorrow to inspect the pump. The good news is that dealing with Hayward support was very quick and easy.

I'm now thinking that my filter may be undersized for the necessary flow that I need for the calculated GPMs. Since it is only a 36sqft DE filter with a GPM of ~70. I've ordered new grids as after inspection I found the "ribs" to be broken on all of the grids (8). I don't expect that this will help with the flow but may help with the filtration of my pool as I can't seem to clear the cloudiness since installing the new pump.

 

[mas985]

What was your old pump model?

In general, a pool should not need much flow rate for circulation. 20 GPM is more than enough for a typical pool and skimmer.

If your pool is cloudy, that has nothing to do with the pump or filter. That is because you have algae growing. A SLAM will clear that up.

Algae in the filter can also explain the lower flow rate.

 

[TNova]

What was your old pump model?

In general, a pool should not need much flow rate for circulation. 20 GPM is more than enough for a typical pool and skimmer.

If your pool is cloudy, that has nothing to do with the pump or filter. That is because you have algae growing. A SLAM will clear that up.

Algae in the filter can also explain the lower flow rate.

Thanks for the reply! My old pump was a Hayward SuperMax 1.5hp single speed pump and was ~ 6 years old before it burnt out.
In regards to the cloudiness, when installing the new pump, I took apart my filter to clean it and check for any wholes etc, in the grids. The grids were not green as they have been before when I had some decent aglae in the past. From what I could tell, looked pretty good, although I did notice that all the ribs in the grids were broken, hence me ordering some new grids (which I haven't received or installed yet). I just recently (Sunday) went to Leslie's and had the water tested. The results were as follows:

pH: 7.4
hardness: 210
FAC: 2.3
CYA:26
Po: 50

Do you think I should still SLAM?

Thanks again for the help!

 

[mas985]

A cloudy pool generally indicates the start of an algae bloom (i.e. before it turns green). You can perform an OCLT if you want to make sure. Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool

Do you have your own test kit? If not that is the first thing you need to do.

Is the filter pressure higher than normal?

 

[TNova]

A cloudy pool generally indicates the start of an algae bloom (i.e. before it turns green). You can perform an OCLT if you want to make sure. Perform the Overnight FC Loss Test (OCLT) - Trouble Free Pool

Do you have your own test kit? If not that is the first thing you need to do.

Is the filter pressure higher than normal?

I do have my own test kit. I believe that I have a Taylor K-1005 kit but I'd have to double-check to be 100% sure. I will definitely perform the OCLT tonight and again tomorrow morning to see. Not sure I ever would have thought to do that (another reason to love this site and its members!) so thank you and thanks for the link! I'll report back tomorrow with the results.

The filter pressure is actually lower compared to what it used to be using the single-speed pump. The pressure on the filter with the old pump would generally start at 22 and move upwards to 30 before I performed a backwash. The new pump install started at about 16 when running at 3250 rpm. If the speed drops to 1750 rpm, then the pressure drops to about 4psi. I have not seen the pressure above 16-18 at any time over the last 5 days.

 

[mas985]

The filter pressure will change with a different pump model. It will also drop with a drop in RPM so all of that is normal.

What I was more interested in is with the current pump, the clean filter pressure vs the current pressure at the same RPM.

 

[TNova]

Morning...

Here is my update after the OCLT performed and there was no visible change in the FC as it registered 2 both at night (10 pm) and this morning (7:30 am) so I don't think that I need a SLAM at this point. Unfortunately, I was wrong and I do not have the Taylor K-2005 test kit and will be ordering a new kit just in case later today. I'll be looking on the site for what the best kits are later today.

In regards to the pressure, with the current pump at the highest rpm (3250), and after a complete cleaning of the DE Filter grids, the pressure registered about16psi. This was 1 week ago. Today, the pressure is still registering at about 16psi.

really appreciate all of the help!

 

[mas985]

Double check the RPM on the MaxFlo. The maximum speed for the MaxFlo should be 3450 RPM. I have the same pump and the speeds are set as % of max speed which should be 3450 RPM.

BTW, you posted a CYA of 26 ppm. How was that measured? That type of resolution is not possible with a standard drop kit. We usually recommend rounding up when determining target levels. So you should have a target of 4-6 ppm for a CYA of 30 ppm. This might be why the pool is starting to get cloudy. That usually happens right before an algae bloom.

 

[TNova]

thanks for the advice... unfortunately I can't check because the display is still out. The service company is ordering a new display for me and will hopefully get in sooner than later. The measurement wasn't from my own test, it was from Leslie's analysis. I will say that the pool is slowly getting clearer. Today is the best it has been since installing the new pump. I have my robot running 2-3 times a day now which seems to be helping.

I get my new grids on Monday and will install them hopefully then. Again... thanks for all the help.

 

[TNova]

UPDATE (hopefully the last): Got the new grids early and installed them. I noticed one small hole in one of the grids that I didn't notice when cleaning them a week plus ago. My guess is that this was contributing to the cloudiness and pushing some of the DE back into the pool. I also directed flow to only the returns in the main pool (shutting off the spa jets - since the spa is integrated into the pool, this won't affect anything with the spa area) which has helped with the current and now surface debris is getting into the skimmer basket now. Thanks again for all the help and suggestions!