Freeze protection mystery

[dntboles]

Howdy, y'all! Oh how I do not miss Minot ND, yet somehow it feels a little like it in South Texas today... if only for a few hours. It is 21 degrees this morning.

I need your help to solve a freeze protection mystery. This has happened at least 4 times now. Freeze protection kicks on and the spa drains completely into the pool. I go out and manually switch the auto valves to fill the spa. Then I switch back so the pump is pulling from the spa drain. Normally it will get some air in the pump so I do it slowly so it doesn't cavitate. Once everything is smooth, I switch back to auto and it works great, alternating between pool and spa modes on its own. Of course this happens around 6 AM, when it finally gets cold enough to kick on.

My first theory involves air in the spa drain lines. Could there be a valve timing issue here? It seemed to work last year when we had our Texas freeze or two. If somehow the spa drain kicked on way sooner than the spa fill, this could occur, but I haven't fiddled with any freeze protection nor spa settings. I put in a SWCG which involved some replumbing and valve swap but everything (pool, overflow, spa modes) all worked fine since then.

It's going to warm up today then freeze mode will kick back on tonight, so here's another chance to fix it. Thanks, y'all!

 

[dntboles]

Having just said all that, I went back out and the spa was running and had dropped a foot. I've now set it all to manual valves, with 20% draining from the spa and 25% filling it, so there's constant flow on both the pool and spa side.

 

[Jimrahbe]

David,

Does your pump shut off when the valves are moving?

What speed is your pump running during freeze protect?

I have no idea what is causing the problem just throwing darts..

Show us some pics of your equipment pad.. I'd like to see how your Return and Intake valves are plumbed. I'd like to see if you have a make-up line that causes your spa to spillover into your pool, or if your Return valve is just offset to allow a constant flow to the spa when in the pool mode.

If you want to troubleshoot the problem when it is warmer, you can just put your air temp probe in a glass of ice water. Air temp is what turns on freeze protect.

I assume the spa is not draining all at once, but rather a little at a time during each transition between pool and spa modes.

Thanks,

Jim R.

 

[dntboles]

Pump shut off: I don't know. I'd say "no," but I'm not out there watching it. But I get where you're headed there. So in theory, the spa mode kicks in, maybe there's some air in the drain line then the valves open to drain the spa, the pump cavitates and then the spa drains into the pool...

Pump speed -- low -- 40 gallons per minute, which right now is 2358 RPM. 40 gpm is my typical speed all the time, unless I specifically go to high speed (80 gpm) or we're in the spa (80 gpm).

Troubleshooting when warmer.... so if I took a glass of cold water and a glass of Belgian tripel, I could hold the water to the temp probe, while drinking the beer... I like where you're headed with that logic!

 

[Jimrahbe]

David,

Thanks for the pic.

In normal operation of the Spa, all the water that is sucked from the Spa drain goes through the pump and back to the Spa. A closed loop.

If the Spa empties, it means that more water is being sucked from the Spa than is returning to the Spa.

In my mind, the only way that can happen is for the Return valve to not be in the full Spa position. (No water going to the Pool)

I can see that happening as the valves slowly move between the Pool and Spa modes.

I would visually look at the Return and Intake valves, and see if they both move at about the same rate, or if the Return valve takes much longer to move than the Intake valve.

If this were my pool, I would set the system up so that the pump shuts off as the valves are moving and see what happens.

To do that select... Menu, then Settings, then Delays, and set valve delay for Yes. Yes means the pump will shut off, No means the pump will not shut off.

It can't hurt to turn it on, and you can always set it back to No if it does not work.

Thanks,

Jim R.

 

[bedelliott]

Howdy, y'all! Oh how I do not miss Minot ND, yet somehow it feels a little like it in South Texas today... if only for a few hours. It is 21 degrees this morning.

I need your help to solve a freeze protection mystery. This has happened at least 4 times now. Freeze protection kicks on and the spa drains completely into the pool. I go out and manually switch the auto valves to fill the spa. Then I switch back so the pump is pulling from the spa drain. Normally it will get some air in the pump so I do it slowly so it doesn't cavitate. Once everything is smooth, I switch back to auto and it works great, alternating between pool and spa modes on its own. Of course this happens around 6 AM, when it finally gets cold enough to kick on.

My first theory involves air in the spa drain lines. Could there be a valve timing issue here? It seemed to work last year when we had our Texas freeze or two. If somehow the spa drain kicked on way sooner than the spa fill, this could occur, but I haven't fiddled with any freeze protection nor spa settings. I put in a SWCG which involved some replumbing and valve swap but everything (pool, overflow, spa modes) all worked fine since then.

It's going to warm up today then freeze mode will kick back on tonight, so here's another chance to fix it. Thanks, y'all!

Hi David,
Just found your thread so I want to run something by you, it looks like we have similar pumps, I have the Pentair Intelliflo VS, model 011018, it's 3-4 years old. I'm in Austin and was also thinking about this past February. I woke up the other day when it was 28 out and my pump was NOT on, but the anti-freeze IS enabled (set to 40-degrees, 1000 rpm). Pentair told me that the anti-freeze function only makes the pump kick on for a few seconds in order to warm up the LED (the "brain" of the unit), then shuts back off - the tech said the purpose of the anti-freeze is not to protect the pump from water inside it freezing/expanding & cracking the pump, it's only to protect the LED/brain. This makes zero sense to me. so when it was below whatever your anti-freeze temp is set to, did it run constantly until the outside temp got back above your anti-freeze set temp?

 

[Jimrahbe]

Elliott,

David has an automation system.. He is using the automation's freeze protect and not the one inside the IntelliFlo itself.. What you heard from Pentair matches my understanding of how the pump works.

Thanks,

Jim R.

 

[bedelliott]

Elliott,

David has an automation system.. He is using the automation's freeze protect and not the one inside the IntelliFlo itself.. What you heard from Pentair is matches my understanding of how the pump works.

Thanks,

Jim

Thanks Jim, the last (of 4) techs I talked to DID mention the SunTouch stuff to monitor air temp & control the pump that way, so I'll look into that. Interestingly, the 4 techs told me 3 different ways the anti-freeze works, so I'm left not knowing how it really works. But for the pump to be programmed to come on for a few seconds to warm the electronics then kick back off, and not have a care in the world about the water in the pump freezing/expanding, just doesn't make sense to me - they just as easily could have had the pump kick on at the set temp then stay on until the temp got back above the set temp, this would protect the entire pump, not just the electronics, and also would likely protect the rest of the plumbing as well. To protect/save the electronics while the water cracks the pump seems a bit misguided. Not sure why they designed it this way, or perhaps the 1 tech that DID tell me the pump senses the outside/air temp and stays on full time until the outside/air temp goes back up, is correct. (which means my pump isn't working correctly) I appreciate your thoughts!

 

[dntboles]

@Jimrahbe and @bedelliott Y'all were both kind enough to reply back to help with my issue I reported. Here's a recap and update.

Freeze protection: As I understand it (and have observed) my Pentair controller turns on freeze protection mode when the air temp gets to 35 degrees and it runs the pump non-stop until it gets above that. It switches back and forth between pool mode and spa mode periodically, maybe every 20 or 30 min, depending on how it's programmed.

Concern: in freeze protection mode my spa drops drains to empty, typically at 3 AM and I have to go out and fiddle with it, making me grumpy.

Cause: My pool was originally chlorine tabs but I converted it to SWCG. Look at the pic of the equipment pad above. Look just below the heater bypass valve by the little blue T valve. That's my booster pump for the Polaris. The plumbing originally split to pool vs spa sooner and the Polaris only went on the pool side. Because I put the Polaris there, water flows through it even when the controller goes to spa mode. And that water goes into the pool, not the spa. In other words, in spa mode, the pump is sucking X gallons of water per minute from the spa and pumping out X gallons, intended for the spa, but some is being lost to the pool through the Polaris booster pump... X-1.

Workaround: manually turn pool/spa valve to always let a little water into the spa, during freeze times of year.

I just wanted to say thank you to you both for taking the time to help figure this out. Merry Christmas y'all!

 

[dntboles]

Wow! It's been a few minutes since I pinned down the cause until I decided to fix it.

Recap: Chlorine puck pool converted to SWCG. I added a heater bypass valve and SWCG but put the output to the Polaris pump BEFORE the spa/pool valve. So when the system switches to spa mode (say for freeze reasons) some water bleeds out to the Polaris, into the pool. Therefore less water refills the spa and the water level drops. Temp fix was the little blue manual valve to block Polaris. Works great for planned spa use, but not for surprise freeze prevention in the middle of the night.



Update: now it's time to fix my error. I'm redesigning the system again to Polaris split to only the pool side.

Here's the original layout, prior to SWCG. Notice the backflow valve before the chlorine puck stack. Was it just to keep heavily chlorinated water from flowing back to the heater when the pump was off?

Question: Do I need a backflow preventer just before the SWCG? I have one just after the heater output already.

Thanks y'all!

 

[dntboles]

Just the process of writing this out helped me realize my goal isn't to move one valve, make room for other stuff, rearrange... it's simple. Move the Polaris T to only the pool side.

Here's my draft design. Yes, I would need to cut and extend a few verticals to make room, but I'm basically just moving the Polaris T (in blue) from the old spot before the SCWG (grey) to the pool side after the valve.

 

[dntboles]

Replumb done. I was able to just make 4 cuts and reuse more than I expected. Some people call it lazy. Others call it inspired creativeness. I will buy a plug for the old Polaris T, shown here with the blue valve handle.

When I cut the spa supply side, water kept rushing up, so I now know that backflow preventer is bad. Parts will arrive today. I drained the spa by just backwashing right back into the pool, once the dirty water flushed out.

While doing so, some water also came out the pool supply side, so I need to rebuild the main valve. Parts on order. Did you know that if you order the parts to pick up at Leslie's Pool Supply, it's 10% off? The funny part is even if it's just one little piece of the entire order. I ordered 7 parts for the rebuild, with 6 being shipped directly to my home, but will drop by to pick up the little washer.

Another side note: when I installed the SWCG a few years ago, I added the heater bypass valve. After yesterday's replumb, I checked variable speed pump energy usage at 40 gpm, which runs for 4.5 hrs/day
- Flowing through the heater = 705 W or 1,157 kWh/yr = ~$156/yr
- Bypassing the heater = 405 W or 665 kWh/yr = ~$89/yr
- 74% less energy used
- Doing a little math, that means I've saved about $200 in electricity from when I completed the initial SWCG and heater bypass valve install. Thanks for suggesting it TFP folks!