On plumbing, deep heaters, and lines

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manoweb

manoweb

0
Apr 14, 2017
152
Hayward CA
Hello. One of the PB mentioned they have an option for "deep heaters" that - after a brief forum search - seem to be the possibility to use the bottom lines that usually are suction to instead send warm water, eliminating cold spots etc. This prompts a question: why isn't this the norm? Is there a reason why traditionally return lines are at the top of the pool?

Assuming a 35x17ft rectangular pool that is what I have in mind, what is considered the state of the art in the amount of suction/return lines taking into account I intend to install solar panels to heat the water?
 
I think it is not typically the norm, because typically it is a non-issue with proper circulation.

There is no state-of-the-art really.

On the suction side:
You need at least one skimmer (at the downwind portion of the pool). A 2nd is never a bad idea. And optionally, you can have a floor drain (which does help with circulation).

On the return side:
Some pool get by with 1-2 returns ... I would think 3-5 would give you a little better circulation.

The presence of solar does not really enter the equation.
 
If you are planning on building a pool, there was a thread started on what members would do different. I will link it up to this post tomorrow. No difference in cold spots of a pool with proper circulation. I would highly recommend 2 skimmers, main drains and at least 6 to 8 return jets, with 2 being in the steps. Have the returns isolated with shut off valves. One valve for the steps, and 2 for each side of the pool. Also have shutoff valves for the skimmers and main drain (separate). Pentair valves with the locking pins are my favorite.

The returns are not necessarily at the top, but the eyeballs are pointing down towards the pool walls and floors. You can purchase fusion returns and circulator types of returns jet to mix the water in a more efficient manor afterwards. This is what I use.

I added an SWG after 3 years as the PB installed a FROG system. You could probably get away with a heat pump, but a gas heater may be also in your project. The rest can be answered later.
 
I have two returns on my pool.
One is the normal near the surface type I run for my swg/regular water.
The other one is for heated water, I put a street 90 on it and a piece of pipe that directs my heated water to within a foot of the bottom.
Heat rises....
 
i have a floor return. in deep end. it is on it's own valve so i can turn it on when i heat the pool to push water into the deep end which is warm. love it. it is down in the deep end by the drains, but is a separate return not a suction line.

another builder who used to frequent here installs a line of returns down the middle of the pool for this reason. depending on length of pool. i was going to do more but i didn't want more plumbing under the pool. another pool builder i spoke with does 3 no matter down middle for that purpose. all on their own valves for control.

i think it's a good idea. some extra pvc and valve with minor time added.

helps us heat more even.

deff start a build thread. it doesn't have to be pictures and such now. just a place for all your thought and stuff. i started mine 2 years ago i think and i just built this summer. my complete plan and builder changed from doing that thread and the people here. that way it's al in one place vs all over the place. my build from page 1 to present is night and day with where my head was. but it taught me what to do and not do.

soooooooo glad my wife had us wait so we could do it how wanted cause we didn't have the exact cash available at the end of last fall. it pushed us to this spring which brought my present pool builder to the game and a finished pool this season vs over winter stall. if i pushed i would have ended up with a nightmare of a builder i feel. i wouldn't have had the 1-1 attention from the small local builder i used. he is the one who pushed for a 1 season finish along with another builder who has been coaching me throughout. i'm really glad i put the braked on and too ka deep breathe. not like i had choice . the wife pulled the purse strings on me. lol but it saved us not knowing it would.

the company i was going to hire is just digging a hole and is planning on plastering before winter!!!!! and i live in the north east of PA. people up here are usually closed by now and they are just digging! this company obviously does not care.

sorry i digressed.

jim
 
I have these "deep heat returns". I have 3 floor outputs, one in the deepest part of the deep end (9ft), one half way up the incline (6ft) and one in the shallow end (3.5 ft). The all come into the pool on one line however and just extend to the bottom. I was charge an extra $500 for these. I will say they definitely seem make the pool warmer faster. I turned them off on the first heating of the pool and then turned them on and you can feel the circulation different with the warm water rising. I have a return valve where I can turn them totally off and just direct water at the 2 sidewall returns near the top of the pool and also the water features count as returns. I have additional floor drains that are not reversible as returns.
 
Deep returns are not really necessary. I have four returns (all shallow), 2 skimmers and a MD. I did this circulation dye test on my pool with the MD turned off:

Circulation Dye Test - See last video

The deep end gets most of the dye fairly quickly which means the returning warm water gets circulated fairly quickly. I also have solar and have done deep water temperature measurements and after about 30 min of run time, the temperature in the deep end is uniform with depth.
 

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Mas985.

Cool video. Based on your expertise, how many returns should a pool have? I have 2 skimmers, MD (dual, but the same line) and 6 returns, plus 2 in the steps. Was this overkill on the pool companies part?

I have seen pools with only 2 returns, main drain and skimmer (deep end only) constantly battle algae (one of my neighbors). Switched over this year to rotating circulating heads and has done wonders for his pool. Wondering with normal return eyeballs, what the magic number would be. Then again, he switched over to TFP methodology this year as the 3" tablets were constantly beating him up.
 
That sounds more like a chemistry problem than a curculation problem. If FC to CYA ratio is too low or marginal, increasing run time or adding fancy returns can help a little but this approach is masking the real problem of too low FC.

Also, the more returns you have, the less the flow rate per return and the slower the exit velocity per return so the circulation may not improve mich with increasing returns after 2 to 4 returns, depending on the shape and volume of the pool. But having extra returns to help keep dirt off the floor is usually worth it.
 
mas985 said:
That sounds more like a chemistry problem than a curculation problem. If FC to CYA ratio is too low or marginal, increasing run time or adding fancy returns can help a little but this approach is masking the real problem of too low FC.

Also, the more returns you have, the less the flow rate per return and the slower the exit velocity per return so the circulation may not improve mich with increasing returns after 2 to 4 returns, depending on the shape and volume of the pool. But having extra returns to help keep dirt off the floor is usually worth it.
Click to expand...

I agree. The only area in question is the steps. I assume the 2" plumbing does help, but the 6 returns are real powerful (with regular fusion returns). Only use these in the fall so all the leaves to not get kicked down in the deep end. All summer long I use the rotating heads to move water. For some reason, the heat pump is providing 2 degrees every 3 hours, instead of the 2 degrees every 4 hours as reported by other members, etc. So I wonder if the mixture of water makes the pool heat up faster (could be). Extremely efficient in the short time that it was installed. Thanks for your continued advice.
 
There really is no reason not to get them. "Most" circulation is good circulation. Just make sure they are plumbed so they can be turned on/off separate from the other returns (like mine). I would suggest 4 waterline returns (1 at each corner). Also get the aimable jets on those returns so you can create whatever flow is best for your pool.
 
I have 2 Pentair valves. One valve controls the yard side and waterfall line (not used and closed). I assume they plumbed it this way to either run the waterfall or the 4 returns. These are all pool returns. The second shutoff valve controls 2 returns and 2 step jets. If I shut one side off, the other side is too powerful. Only wished that the steps would have been plumbed separately.

The positive is that dirt is kept off the floors. Only leaves that drop once in a while get sucked to the bottom and have to be picked up. Outside of this, the skimmers, along wit the main drains pick up most of the dirt. Socks in the skimmers really help. My pressure rises maybe 2 PSI in a 5 month period. Backwashing is once a year at most.
 
Catanzaro said:
So I wonder if the mixture of water makes the pool heat up faster (could be).
Click to expand...
The amount of heat that the heater delivers is based upon is BTU rating and so that is fixed. However, the variable is the amount of heat that is lost. Mixing up the water can be good or bad for heat loss depending on how it is done. Creating a lot of churn on the surface will increase evaporation as would a layer of hotter water.

As for the heat delivered to the pool, the rating of a heat pump is nominal as a specific outdoor temperature. In this case, it is 80F. Above 80F and the efficiency improves and will deliver more heat although it should not be that much more.

But don't forget that the sun adds heat during the day so did you do this heat gain measurement at night?
 
But don't forget that the sun adds heat during the day so did you do this heat gain measurement at night?
Click to expand...

Mas:

No, the testing I did was during the day only. The test with all 6 circulators in the pool was not tracked like the spreadsheet I originally designed. Please see link below with the testing.

Heat Pump recommendations - Gulf Stream - Page 2

Post # 30

Additionally, I will try this out, but the experiment may be a little costly. Unless I can borrow 250' to 300' of black sears hose. My waterfall line is plugged with a 2" threaded cap. There is a shut off valve in the lines. If I can reduce this cap to a normal hose connection, then I can place on my grass in a large circular pattern and reroute the hose to the pool. Yes, it will look ugly, but I can control the flow of the water with the shut off valve. This may give me some extra heat, but the movement would have to be slow. I also though about rerouting the line to a solar heater and back to the pool. Everything would be visible on the concrete.
 
If you did it during the day then the extra heat you are getting beyond 117k BTU is likely from the sun. It is fairly easy to get a 3-4 degree rise per day in most pools from just the sun.
 
mas985 said:
If you did it during the day then the extra heat you are getting beyond 117k BTU is likely from the sun. It is fairly easy to get a 3-4 degree rise per day in most pools from just the sun.
Click to expand...

Pool is closed, but I will turn on the heater at night and run through the whole night next year to see what the true efficiency of the heat pump is. As usual, thanks for advice.
 
Another question on plumbing. One of the pool builders was very proud they only use 45 degrees elbows for the pool plumbing (he even had 45 elbows samples in his car) because he says it makes a huge difference in the flow. I know for example that the building department does not want 90deg elbows for waste drains (unrelated to pool, it came up when designing the outdoors kitchen) so there might be real reasons behind this claim. Opinions?
 

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