Winterizing solution...

[generessler]

Hello all! In North Carolina where my pool lives, owners seem to be 50/50 run all winter vs. close.

I've had no success finding someone who will provide a decent cover for our pool.

The last attempt was a walk-around with a guy of 30 years experience from the vendor (Myatt installer) recommended in the thread linked above. He said I'm best off keeping it open. He would not sell me a cover even when I said I was good for up to $10k. (Yes. Desperate.) Sigh... I don't like betting on Duke Energy to provide power through every cold night. Their track record is not good.

But if I need to keep the pool running, at least I want to be smart about it. So I'm collecting thoughts, especially about one thing explained below.

The Jandy automation does a decent job of freeze protection: at 34F, turns on whatever I tell it to. Late November to mid-March mainly.

This summer I replaced the single-speed main filter pump with a VSP. So freeze protection got a lot more efficient in that area. In 2 years, min water temp has been 39F and normally mid-40s. So all we need to do is keep water moving at a low rate. Nothing ever ices. Thank you global warming .

I do blow out and seal off the deck jets. So at least they don't need to be spraying all night like the start of first winter... (The prior owner didn't run them. There was freeze damage when we moved in.)

That leaves the bubbler pump for the spa. It's a 3hp monster. I hate running that every cold winter night for 8-12 hours. Silly. We do love heating up the spa, e.g. on New Years Eve. Woohoo! But we'd be fine with no bubbler in freezing weather.

Sooo.... here is the main question:

The equipment pad is at spa water level. (Pool is lower.) Frost depth in NC is 12 inches.

So If I disconnect and drain the bubbler pump (via new unions I'll install), I believe the only thing that can freeze is 12 inches of supply and return pipe from pad level to 12 inches below.

12 inches ought to be a true worst case. Afaict, only an inch or two of soil has actually frozen in the past two winters even with some single digit nights. The pad is adjacent to the house, so there's probably latent heat to help out. The rest of the pipe ought to be below frost depth. Or is that wishful thinking?

So how to make those 2 x 12 inch sections freeze safe? My idea is to displace water with 2" closed-cell foam backer rod pushed as far down the pipe as possible. Even if some water around them freezes, the rod will allow expansion without bursting pipes. Just like a gizmo in a skimmer.

So what to you all think? Will this work? My thought is that if running all winter means only the VSP at low revs, I'll sleep a lot better through the longest nights of the year.

THANKS for your ideas as always.

 

[mas985]

So If I disconnect and drain the bubbler pump (via new unions I'll install), I believe the only thing that can freeze is 12 inches of supply and return pipe from pad level to 12 inches below.

12 inches ought to be a true worst case. Afaict, only an inch or two of soil has actually frozen in the past two winters even with some single digit nights. The pad is adjacent to the house, so there's probably latent heat to help out. The rest of the pipe ought to be below frost depth. Or is that wishful thinking?

Technically a pipe should never burst as long as there is over 10% air, by volume, within the pipe. Pipes only burst when is there no room for the ice to expand, usually at closed valves. Also, any pipe below the frost line will absorb heat from the surrounding soil and transfer it to the pipe above the frost line via water conduction/convection delaying the freezing until most of the pipe is below the frost line. I really don't think you have anything to worry about given your location.

 

[ajw22]

even when I said I was good for up to $10k. (Yes. Desperate.) Sigh... I don't like betting on Duke Energy to provide power through every cold night. Their track record is not good.

You have NG. For that money spend it on a Generac backup generator.

Then if want a further backup have a spare pump in case your pump fails.

As long as you have power and a pump you will be good.

Final fallback is know where your equipment drains are and have a blower to be able to winterize your pool and probably your house if you have a Texas type deep freeze that even runningw ater cannot overcome.

 

[generessler]

You have NG. For that money spend it on a Generac backup generator.

Then if want a further backup have a spare pump in case your pump fails.

As long as you have power and a pump you will be good.

Final fallback is know where your equipment drains are and have a blower to be able to winterize your pool and probably your house if you have a Texas type deep freeze that even running water cannot overcome.

Thanks. Yes I'm thinking about backup power. The property doesn't have a great place to put a generator and its fuel. I'm looking at Power Wall kinds of battery setups that will at least give me 24 hours or so to get everything drained and blown. Yeah I have an emergency plan for that. Hope it's never needed.

 

[generessler]

Technically a pipe should never burst as long as there is over 10% air, by volume, within the pipe. Pipes only burst when is there no room for the ice to expand, usually at closed valves. Also, any pipe below the frost line will absorb heat from the surrounding soil and transfer it to the pipe above the frost line via water conduction/convection delaying the freezing until most of the pipe is below the frost line. I really don't think you have anything to worry about given your location.

Thanks. That's reassuring. I think you're right because the conduit for the spa light is in the same shape. Water comes to ground level. Nothing to stop freeze expansion. And it was like that all the time the previous owners ran the pool all winter (afaik, 14 years) with apparently no problems.

So overall, sounds like my plan is okay. When I remove the bubbler pump the water level in the pipes is at ground with nothing to block expansion. So the closed cell foam is optional. I'll probably do it because it's so easy.

 

[mas985]

Skimmers can also be an issue because of their odd shapes so ice can get trapped and cause damage. Either foam or lowering the water level can mitigate the risk.