Recommended Operation for Spa/Pool

Jul 22, 2018
6
San Diego, CA
#1
Hi there

I have a SPOOL in my vacation rental in SoCal. Guests pay me a $20 per day fee to heat both the pool and the hot tub. I'm trying to figure out a heating schedule that makes the most sense from an energy efficiency point of view and which is also convenient for my guests.

Most guests seem to use the hot tub in the morning and in the evenings. Currently I have the filter and pool heat running from 8am to 4 pm. If they use the hot tub in the morning before the filter has come on then the hot tub heats up reasonably quickly (15-20) depending on how much heat it has lost from the night before. If they use the hot tub after 8am, the hot tub temperature has dropped to whatever the pool was at and it takes a bit longer and "costs" more energy.

Does anyone else have a similar setup and is it appropriate and efficient to do it this way? Is there a better way that is more efficient and or more convenient?

Thanks in advance
KIWI
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,126
Pleasanton, CA
#2
Welcome to the forum!

If you are not using a cover, it is probably going to cost a lot more than $20 to heat the pool. Other than a cover, nothing else matters that much.
 
Jul 22, 2018
6
San Diego, CA
#3
Welcome to the forum!

If you are not using a cover, it is probably going to cost a lot more than $20 to heat the pool. Other than a cover, nothing else matters that much.
Actual cost is around $25 per day.
The heater increases pool temp 2° per hour or Hot Tub temp 40° per hour. I'm not that worried about the cost as I have seen enough usage to know what it costs. I'm just not sure if I have it setup correctly so it's easy to use. I have them locked out from making changes, other than turning the filter on/off and turning spa mode on/off. Maybe I'm trying to overthink it and it's simple enough already.
 

Dodger

Silver Supporter
Sep 18, 2017
477
Silicon Valley, CA
#4
If they use the hot tub in the morning before the filter has come on then the hot tub heats up reasonably quickly (15-20) depending on how much heat it has lost from the night before. If they use the hot tub after 8am, the hot tub temperature has dropped to whatever the pool was at and it takes a bit longer and "costs" more energy.
I could be way off, but here's what your description sounds like to me.

Before 8am, the hot tub water is warm from the night before - warmer than the pool water because of the nighttime use that heated it to, say, 100 degrees. Even though it will cool some during the night, it won't drop down to the pool temp. Because it has retained some heat, it reheats pretty quickly the next morning before the normal filter schedule starts at 8am.

When the filter schedule starts at 8am for pool heating, you are heating the pool with valves in the spillover position rather than pool-only position. If that's the case, you are taking in cooler pool water through the pump and filter, and returning that cooler water to the hot tub. This pushes the warmer residual water out of the hot tub, over the spillover, and into the pool. By 8:30 or 9am, if your guests turn on the hot tub, the cooler water that is there now needs a lot more heat/time to meet the setpoint.

Could this be the case?
 
Jul 22, 2018
6
San Diego, CA
#5
I could be way off, but here's what your description sounds like to me.

Before 8am, the hot tub water is warm from the night before - warmer than the pool water because of the nighttime use that heated it to, say, 100 degrees. Even though it will cool some during the night, it won't drop down to the pool temp. Because it has retained some heat, it reheats pretty quickly the next morning before the normal filter schedule starts at 8am.

When the filter schedule starts at 8am for pool heating, you are heating the pool with valves in the spillover position rather than pool-only position. If that's the case, you are taking in cooler pool water through the pump and filter, and returning that cooler water to the hot tub. This pushes the warmer residual water out of the hot tub, over the spillover, and into the pool. By 8:30 or 9am, if your guests turn on the hot tub, the cooler water that is there now needs a lot more heat/time to meet the setpoint.

Could this be the case?
Yes, that's 100% correct.

Sorry, I'm new and wasn't familiar with the terminology. Is it possible to run the filter without "spillover" mode so that the hot tub is not impacted? To maintain the water level in the tub it would need to run in spillover mode at least some of the time, right?

Should I change something or is this the typical setup? Is there a better way?
 

Dodger

Silver Supporter
Sep 18, 2017
477
Silicon Valley, CA
#6
Yes, you need to run spillover probably once per day in order to refresh the water in the hot tub (spa). So you will "lose" that residual heat in the spa at some point.

But with the cost/efficiency angle you originally asked about, I would think that starting the spillover in the morning is the least beneficial choice. Morning is when the pool water you are sending to the spa is the coolest. Instead, I would just run the spillover toward the end of the 8-4 filter cycle.

On the other hand, if the temp change of the pool from 8am to its setpoint is only a few degrees difference, then I don't think it's going to save you more than a buck or 2 per day.

Mostly, this will improve your guest's experience with a shorter time to heat the spa in the morning, either before or after 8am.


To run without spillover, you need to share more about your equipment setup. What kind of automation do you have? And what does the return valve look like when in regular filter mode? One possibility is that your return valve was set to not close all the way, causing an artificial spillover rather than an automation-spillover.
 
Jul 22, 2018
6
San Diego, CA
#7
Yes, you need to run spillover probably once per day in order to refresh the water in the hot tub (spa). So you will "lose" that residual heat in the spa at some point.

But with the cost/efficiency angle you originally asked about, I would think that starting the spillover in the morning is the least beneficial choice. Morning is when the pool water you are sending to the spa is the coolest. Instead, I would just run the spillover toward the end of the 8-4 filter cycle.

On the other hand, if the temp change of the pool from 8am to its setpoint is only a few degrees difference, then I don't think it's going to save you more than a buck or 2 per day.

Mostly, this will improve your guest's experience with a shorter time to heat the spa in the morning, either before or after 8am.


To run without spillover, you need to share more about your equipment setup. What kind of automation do you have? And what does the return valve look like when in regular filter mode? One possibility is that your return valve was set to not close all the way, causing an artificial spillover rather than an automation-spillover.
I have an iAqualink system and can remote control everything. It was all there when I purchased the house and I'm slowly figuring things out.

Here's some pictures:
LQ Pool Equipment - Google Photos

I do have a pool guy so perhaps I'll see what he says about configuring the spillover to operate from 12-4.

Thanks for your help, I really appreciate it.
 

Dodger

Silver Supporter
Sep 18, 2017
477
Silicon Valley, CA
#8
Great. Does the iAqualink Status show "Spillover" during the 8-4 period? If yes, then you most likely have a proper automation controlled spillover. That is easy to reprogram if you want to DIY.

If you go into the Menu->Schedule screen, you probably see Spillover programmed from 8-4. You'll just want to Edit the Start time for that to 12 noon and Save.

Then you can Add a schedule to run the valves in normal Pool Mode before noon. On my iAqualink, this is called "Filter Mode", but it may have a slightly different name for yours. It's the most basic valve setting, so it's usually the first option in the list. Set that up with an 8am Start and either 12 noon or 4pm Stop. The latter is fine, since the Spillover program overlays Filter Mode and will take precedence from noon to 4.
 

mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,126
Pleasanton, CA
#10
The PB may have plumbed a constant spillover bypass when in Pool Mode. Can you post a picture of the equipment pad?

Stopping it may not help heat retention much because in most cases, most of the heat will be lost before the spillover even turns on.
 

Dodger

Silver Supporter
Sep 18, 2017
477
Silicon Valley, CA
#11
It would also help to see a top down picture of the automated return valve to see if it is 100% closed to the spa when in filter pump / pool mode. Also, you should manually test the valve via the toggle switch underneath to make sure it hasn't been disabled (center position of the switch) into a permanent spa return.

If you don't see Spillover as a Device option in your iAqualink, then most likely the dip switch for Aux3 was never set up. That's a DIY (I've done it myself), or your pool guy can do it. If you have something else already hooked up to Aux3, like lights or water feature or air blower, you have to move it to an open Aux to free up Aux3.


Mark, I understand about the overnight heat loss, but it should help at least a little bit because KIWI states that he sees 2 distinct heat-up patterns for the spa in the morning. One is only 15-20 minutes when spillover has not run. The other one is longer. So clearly the heat loss is not complete overnight.


Edited: I just noticed the photo link you had in post#7. From that angle, maybe Mark can identify if there is a permanent spillover plumbed. He is smarter than me. :)
But I see that Spillover is not in your Device list, so the option to set up Aux3 is there if it ends up making sense. You'd have to move Pool Light, which is currently occupying your Aux3 in the list.
 

Dodger

Silver Supporter
Sep 18, 2017
477
Silicon Valley, CA
#12
Looks like there is a bypass before the automated return valve at the top of your plumbing. A ball valve, with a blue handle, controls whether some water diverts to the spa down that pipe with the check valve.

The blue handle on the ball valve should be fully closed, perpendicular to the pipe, if you want to shut off permanent spillover via that route.

But since that ball valve is manual, you'd need to set up the Aux3 and create a program to do the spillover automatically via the automated return valve. Otherwise you won't be able to refresh the spa water.

May not be worth all that effort for the small improvement on the heat issue. But I'd personally do it to maximize my automation options. Especially since you don't live there and rely on remote access even more.
 
Jul 22, 2018
6
San Diego, CA
#13
Looks like there is a bypass before the automated return valve at the top of your plumbing. A ball valve, with a blue handle, controls whether some water diverts to the spa down that pipe with the check valve.

The blue handle on the ball valve should be fully closed, perpendicular to the pipe, if you want to shut off permanent spillover via that route.

But since that ball valve is manual, you'd need to set up the Aux3 and create a program to do the spillover automatically via the automated return valve. Otherwise you won't be able to refresh the spa water.

May not be worth all that effort for the small improvement on the heat issue. But I'd personally do it to maximize my automation options. Especially since you don't live there and rely on remote access even more.
Thanks guys. I will probably have my pool guy look at it for me next time he's on-site.