Solar Heating and Suction Driven Pool cleaners

[chriszke]

I've googled my problem into oblivion...without satisfaction. That's how I found this forum though...so all was not in vain.

Here's my problem.

I've got a 24" above-ground pool that I installed last year. I live in Michigan and wanted to give the pool a slight temperature boost...as well as extend the swim season. I installed two sunheater (2x20) solar heaters in series and was pleased with the outcome. A timer runs the pump automatically from about 9 am till 6pm, and we pickup plenty of heat during the day. A solar cover keeps the heat in at night...but we'll keep it off during extremely warm periods to maintain a preferred 82-86 temperature range. This spring, I was given a third 2x20 solar heater by a co-worker which I installed in series with the previous two.

Here comes the problem.

We were given a used Kreepy Krauley by a neighbor. Earlier this year...and before I hooked up the solar heaters, I ran the Kreepy multiple times and was amazed by the speed at which the device scampered around the pool. My pool bottom was spotless in about 2 hours time.

With the addition of the 3 solar heaters, my GPM flow has dropped considerably. I still get plenty of heat, but GPM decrease has slowed the Kreepy "scamper" to a much slower "crawl" (pun intended).

I've considered a couple of solutions which I'll lay out, but would appreaciate any other suggestions that you might have.

One solution would be to install a bypass to the solar heater system. This should allow me to regain my original GPM flow, and run the Kreepy whenever I choose (even at night when solar heat collection can't be done).

Another soluation which came to mind was to re-plumb the 3 2x20 mats in parallel. My assumption here though, is that running the solar heaters in parallel would increase my GPM flow back to "near-heaterless". I'm also wondering whether the effectiveness of the heaters would increase given an increase in flow-rate.

I suppose the best of both worlds would be to do both. Given that I'm currently satisfied with solar heating performance though...I'm really most concerned about solving what I perceive to by a GPM flow issue...which is degrading my Kreepy Krauley performance.

Anyone else run into a similar dilemma? If so...I'd appreciate any other perspectives...

Thanks, Chris

 

[Rangeball]

I don't know what your cost would be for replumbing or what the minimum flow for the KK is, but I've been looking at suction cleaners lately and many claim being able to work at low flow, like down to 12-15 gpm, at a cost of about $125 (the lil'shark for example).

Other than that I'd be inclined to go with the by-pass, as you're current solar set up is proven for heat generation.

 

[JohnT]

I'm not familiar with AG pool solar, but parallel is a way better way to plumb them in other applications. The problem with a series connection from a heating perspective is that the water is warmer at the heaters downstream, so the collectors are less efficient. Plumbing them in parallel provides better flow, and each heater has the coldest water possible entering it, which maximizes the heat transfer from the panel to the water.

 

[JasonLion]

The panels will be more efficent and last longer and you will get a better flow rate if you pumb them in parallel. Panels are typicaly designed for 4 or 5 GPM, while the pool generally wants 20-50 GPM.

 

[chriszke]

I'm not familiar with AG pool solar, but parallel is a way better way to plumb them in other applications. The problem with a series connection from a heating perspective is that the water is warmer at the heaters downstream, so the collectors are less efficient. Plumbing them in parallel provides better flow, and each heater has the coldest water possible entering it, which maximizes the heat transfer from the panel to the water.

I'd have to think John...that the physics of the heat transfer wouldn't change given the above-ground application.

That's what makes the plumbing solution a bit more attractive (but also slightly more labor intensive). I'd have the added benefit of a more effective heat-transfer system. More horsepower available, as it were...when I wanted or needed to use it.

 

[NWMNMom]

Well, from personal experience I can tell you that

1) We do have a diverter/by-pass system on our panels and it is easy to install and is very helpful for adding a bit of a power boost to the pressure when using a suction side cleaner. We also just divert when the water starts getting too warm OR if we need to filter some icky water or issue and its cloudy or night time, so we don't cool off the water.

2) We have our 4x20 panels run parallel and feel the BTUs are more than sufficient (better than the 4 2x20s we used to have in a series)

3) We have the Lil Shark and it works pretty quickly at a very low flow, its just not the best cleaner for odd shaped pools that have edges, inclines or structures - round pools with flat bottoms (no deep inclines) works best for this one - its not BAD, it just needs a bit of help with odd shaped areas so is not the cleaner for people who want to drop it in and go to bed.

 

[chriszke]

Thanks all,

My immediate response will be to build in the diverter. It's couple hour weekend project, and I'm short of time on upcoming weekends.

I'll re-do the plumbing on the solar heaters by summers end...likely just in time for pool close (grin).

Appreciate the help.

Chris

 

[pooladdict]

Ok confused here, I have the cold water entering one panel, leaving it, and going into the other...is this wrong? Made sene to me when I did it, and would be alot more work to have it going into the both at same time. I can tell u that when I had the first one up there, the flow rate is still the same. Just installed a solar controller, and limited the amount of water into panels by 50%...not sure of my flow rate or how to guess it, but my Aqua Garden and two jets all have sufficient power then the controller diverts water to the Panels.

Do I need to change this?

Rik

 

[JasonLion]

pooladict - you don't need to change anything, but your system will be more efficient if you plumb the panels in parallel. The rate of energy gain is proportinate to the temperature difference. The first panel is heating the water, so the second panel is seeing hotter water, and so has a smaller potential temperature difference, and so is less efficient.

 

[andysutt]

Well. my solutions include this:

Ditch one of the solar panels and send it to me or the other is ditch your cleanre and send it to me. lol

Anyways, I also agree that running then in parallel would be alot better all around.

 

[pooladdict]

I wonder if anyone has a mock up of how panels should be placed on a roof. The kind I have has water entering the top, being rerouted down one side, and up the other. I guess a t might work?

Rik

 

[NWMNMom]

Water always enters each of the panels at the bottom and leaves at the top - this is designed to flush air from the system

 

[matt4x4]

kreepy...

I find that any kreepy crawley that scampers around doesn't actually clean your pool, mine runs around like crazy with a clean filter and no solar, all it does is stir up the dirt, stop the pump for a day and see how much dirt you got again, probably the same as you had before.
I try to let my filter get somewhat dirty, turn the solar on and let it run then, it's less than half the speed, but doesn't create the plumes of dust you would see under full throttle conditions, in the end it probably catches 2/3rds the dirt, because at best, I find kreepy crawley's to be very limited in their cleaning ability.

What you're experiencing is completely normal - a dirty filter will also produce this result - your cleaning ability is actually improved with both a dirty filter and restricted flow.

 

[chriszke]

Re: kreepy...

I find that any kreepy crawley that scampers around doesn't actually clean your pool, mine runs around like crazy with a clean filter and no solar, all it does is stir up the dirt, stop the pump for a day and see how much dirt you got again, probably the same as you had before.
I try to let my filter get somewhat dirty, turn the solar on and let it run then, it's less than half the speed, but doesn't create the plumes of dust you would see under full throttle conditions, in the end it probably catches 2/3rds the dirt, because at best, I find kreepy crawley's to be very limited in their cleaning ability.

What you're experiencing is completely normal - a dirty filter will also produce this result - your cleaning ability is actually improved with both a dirty filter and restricted flow.

That's an experiment worth trying, but we were pretty impressed by the kreepy's performance earlier this summer...pre-solar heater.

The problem with the restricted flow though...at least for me...is that even 4 or 5 hours of kreepy vacuuming doesn't seem to give the device time enough to cover the entire bottom of the pool, given the relative randomness of the cleaning pattern.

During the summer, the pool is used virtually every day...and there is rarely a 6-8 hour window to run the automatic vacuum.

A rainy day would give me the chance to set-up and run the cleaner for an extended period of time...but there have been precious few of those so far.

 

[anotherpyr]

Re: kreepy...

I find that any kreepy crawley that scampers around doesn't actually clean your pool, mine runs around like crazy with a clean filter and no solar, all it does is stir up the dirt, stop the pump for a day and see how much dirt you got again, probably the same as you had before.
I try to let my filter get somewhat dirty, turn the solar on and let it run then, it's less than half the speed, but doesn't create the plumes of dust you would see under full throttle conditions, in the end it probably catches 2/3rds the dirt, because at best, I find kreepy crawley's to be very limited in their cleaning ability.

What you're experiencing is completely normal - a dirty filter will also produce this result - your cleaning ability is actually improved with both a dirty filter and restricted flow.

Kreepys are supposed to run at a specific rate which is adjustable. Some where I have a video that talks about the particular sound it is supposed to make. It if runs too fast it doesn't clean, if it runs too slow it doesn't clean. So if you have too much suction the kreepy dances along the bottom of the pool and stirs everything up. Not enough and it barely moves or picks anything up.

 

[matt4x4]

My pool is being used heavily on a daily basis, it's been 6+ kids several times daily for 1+ weeks now, but I'm not seeing any Crud accumulate so I haven't had to vacuum in a couple of weeks - there's the odd leaf, the odd bug, but nothing else collecting on the bottom, I usually vac when i see a few spots of dirt accumulating, outside of that, if there's no dusting or anything I don't bother. I do cover it over night with the solar blanket which likely keeps a lot of Crud out of the water, and run the filter 8:00 to 6:00pm, but even then, my pressure hasn't risen in weeks either...
Probably vac it this weekend though, a nice relaxing thing to do really early saturday mornings watching the sun come up....