Winterize Pool but not Spa with Shared Equipment

[Bensmith82]

Sorry in advance for the long post. I am a first year pool owner in Utah (Cold Snowy Winters). I have a pool/spa combo with shared equipment. I want to winterize my pool, but continue to use my spa in the winter and have been looking for advice on what to do. I came across this article online that provides info about how shared systems work:

Shared Pool & Spa Systems

The article says:

“If you live in a cold climate area where the pool will need to be closed and winterized then you will also need to close and winterize the spa if they share equipment. For some people that is no problem, for others, like myself, the cold weather is the besttime to use a hot tub, and closing mine for the winter would be out of the question.”


I have an automated shared system gunite pool with a main drain and in-floor returns. All of my pool equipment is an an insulated, heated shed with a generator backup for power outages. Wouldn’t it be possible to blow out the main drain, skimmers, and pool floor returns simultaneously while in pool mode using a cyclone blower attached to a modified pump lid, and then air lock the main drain, skimmers, and pool return lines by switching the system into spa mode? My understanding is that switching the system to spa mode closes valves on the pool return lines, main drain, and skimmers so that the system draws water only from the spa and returns water only to the spa. Is my understanding correct and would this work to airlock/winterize the pool plumbing?

If so, then I could just make sure that I leave the system in spa mode all winter long to maintain the airlock in the pool. Please let me know if you think this would work or if there is something I am missing.

Also wondering if you would try to plug the floor returns with a rubber plug after clearing them while continuing to blow air through the pool plumbing or if you think the air lock is sufficient. I’m a belt and suspenders kind of person, So if plugging them after blowing air through the system to clear them wouldn’t hurt anything, and could only provide additional protection, I’m likely to try to plug them.

Please let me know your thoughts. Thanks in advance!

 

[HermanTX]

All of my pool equipment is an an insulated, heated shed with a generator backup for power outages. Wouldn’t it be possible to blow out the main drain, skimmers, and pool floor returns simultaneously while in pool mode using a cyclone blower attached to a modified pump lid, and then air lock the main drain, skimmers, and pool return lines by switching the system into spa mode?

This is definitely a positive to have a heated shed with backup generator so you can maintain the equipment running in the dead of winter.
I would not rely on just the automated valves to hold your air lock so if you are able to put plugs in the lines leading to and from the pool then that should work. you may want to post some pictures of your equipment pad.

Calling @Newdude to give you some hands on experience and advice.

 

[Newdude]

Air locking only works on the main drain because it's a 'down pipe'. Stick your finger over a straw and conpletely dunk it and the air has nowhere to go so it remains. Turn the straw sideways (like the returns through the wall), or upside down (pipe below skimmers) and it will glug glug out and fill with water.

So the skimmers and returns need to be plugged while the main drains do not.

With the pool plumbing blown and capped, it would work if your heater was capable of overcome the ambient temps, which many can't do when it's near or below freezing in the shed. You would also need to leave it running 24/7 during cold spells.

 

[wireform]

But then again heaters are designed to keep the water above 70° and not let's say 45° otherwise the condensation eats them up. Are you ready for that if it's at all possible without a cover. I know of one IG pool that remains open all year here in the north east and all it has is the automatic cover. Yes it retained temperature last year even in 5° temps but the heater had a hard time and it also went through a control board in the heater due to condensation. It was a race for time while the new board was being shipped so the pipes don't take a hit. Now they're building a shed around the equipment and will have heated air to help with the condensate problem, so just more to avenue to think about before you decide either way.

 

[Bensmith82]

This is definitely a positive to have a heated shed with backup generator so you can maintain the equipment running in the dead of winter.
I would not rely on just the automated valves to hold your air lock so if you are able to put plugs in the lines leading to and from the pool then that should work. you may want to post some pictures of your equipment pad.

Calling @Newdude to give you some hands on experience and advice.

Air locking only works on the main drain because it's a 'down pipe'. Stick your finger over a straw and conpletely dunk it and the air has nowhere to go so it remains. Turn the straw sideways (like the returns through the wall), or upside down (pipe below skimmers) and it will glug glug out and fill with water.

So the skimmers and returns need to be plugged while the main drains do not.

With the pool plumbing blown and capped, it would work if your heater was capable of overcome the ambient temps, which many can't do when it's near or below freezing in the shed. You would also need to leave it running 24/7 during cold spells.

Thanks for the response, I really appreciate you taking time to provide advice and expertise! Like the main drain, my returns are in the floor of my pool, so would they also be considered "down pipes"? If so, would an air lock work for the floor returns in my situation? I found these "Duck Plugs" in a previous post from another user:

Amazon.com

I am considering using the Duck Plugs as an additional line of defense (assuming airlocking the floor drains is a viable option). Water will be drained 1" below skimmers, blown out, and plugged with a Gizmo.

My shed is insulated and I have a space heater that keeps the temperature inside the shed at 50 degrees through the winter. I plan to keep the water in the spa at 75 degrees at all times when not in use (to avoid condensation problems with the heater) and I will run my variable speed pump on low. The generator will kick on automatically if the power goes out to keep the space heater and pump running. I have an auto-cover, so hopefully that will help retain some of the heat.

 

[Bensmith82]

But then again heaters are designed to keep the water above 70° and not let's say 45° otherwise the condensation eats them up. Are you ready for that if it's at all possible without a cover. I know of one IG pool that remains open all year here in the north east and all it has is the automatic cover. Yes it retained temperature last year even in 5° temps but the heater had a hard time and it also went through a control board in the heater due to condensation. It was a race for time while the new board was being shipped so the pipes don't take a hit. Now they're building a shed around the equipment and will have heated air to help with the condensate problem, so just more to avenue to think about before you decide either way.

Thanks for the feedback and for this important advice! I read previously on this forum about condensation issues with heaters if you don't keep the water above 70 degrees. I found the same instructions in my heater's user manual. I will only keep the spa open in the winter and the spa is just over 2,000 gal. I would hope that my 400,000 BTU Master Temp heater won't have any problems keeping up. Insulated, heated shed is already in place around my pool equipment. Equipment failure (heater, pump, control board, etc.) seems like it could be a weak link though. Thanks again for your thoughts.

 

[Newdude]

Like the main drain, my returns are in the floor of my pool, so would they also be considered "down pipes"? If so, would an air lock work for the floor returns in my situation?

If they are through the wall then they are 'sideways straws' and the air will glug out. On the other side of the wall they likely drop several inches and that will all fill as well.

But. How deep are they ? If they're well below the frost line, then it's not an issue but you get real winters so they'd likely have to be deeeeeep. Lol.

*edit, i just looked it up and i have a similar frost line as you, between 30 and 40 inches. We've never seen ice more than 2 ft thick and that was historic if it happened, so your deep water returns are likely fine from the front, and possibly ok on the pipe side.

I found these "Duck Plugs" in a previous post from another user:

I did not like my duck plug. The 'lips' were paper thin and chintzy and the ice pulled the protective cap off mid winter, leaving them exposed for the remainder. Instead use Bungee plugs which are more robust.

Seeing how you have to get in there either way, you could also use standard threaded return Plugs and cap them with air shooting out. It's half a dozen or six and you're both cold and wet no matter what. Lol.

 

[Bensmith82]

If they are through the wall then they are 'sideways straws' and the air will glug out. On the other side of the wall they likely drop several inches and that will all fill as well.

But. How deep are they ? If they're well below the frost line, then it's not an issue but you get real winters so they'd likely have to be deeeeeep. Lol.

*edit, i just looked it up and i have a similar frost line as you, between 30 and 40 inches. We've never seen ice more than 2 ft thick and that was historic if it happened, so your deep water returns are likely fine from the front, and possibly ok on the pipe side.

I did not like my duck plug. The 'lips' were paper thin and chintzy and the ice pulled the protective cap off mid winter, leaving them exposed for the remainder. Instead use Bungee plugs which are more robust.

Seeing how you have to get in there either way, you could also use standard threaded return Plugs and cap them with air shooting out. It's half a dozen or six and you're both cold and wet no matter what. Lol.

Bungee plugs look way better. Thanks!

 

[Bensmith82]

If they are through the wall then they are 'sideways straws' and the air will glug out. On the other side of the wall they likely drop several inches and that will all fill as well.

But. How deep are they ? If they're well below the frost line, then it's not an issue but you get real winters so they'd likely have to be deeeeeep. Lol.

*edit, i just looked it up and i have a similar frost line as you, between 30 and 40 inches. We've never seen ice more than 2 ft thick and that was historic if it happened, so your deep water returns are likely fine from the front, and possibly ok on the pipe side.

Sorry, just read this part of your post closer. The returns enter the pool through the floor (not the wall). Our pool goes from 3ft to just over 5ft and the returns are somewhere in the middle. Can you explain what you mean by "fine from the front" and "possibly ok on the pipe side"?

 

[Newdude]

The returns enter the pool through the floor (not the wall). Our pool goes from 3ft to just over 5ft and the returns are somewhere in the middle.

Ok. Then floor returns around 4 ft deep don't need to be plugged. You can, just because, if you'd like.

Can you explain what you mean by "fine from the front" and "possibly ok on the pipe side"?

The pool won't freeze as deep as the frost line. On cold years, climates like ours might see 12 to 18 of inches of ice, but pipes buried at 3 ft might freeze. So if your deep returns were wall returns at 2 to 3 ft, the pool side wouldn't freeze but the ground side might. At 4 ft down, you're golden on both sides until the pipes rise to the pad. It's usually at the pad, but not always.

IMO the patio helps shield the ground beneath it because the stone/cement warms up in the sun and retains some of that heat into the night. So the frost line wouldn't be as deep under the patio, but it's simply not worth the thousands of dollars of risk to test that theory.