I’ve run into that same air lock issue with drainback, and it’s a pain to track down unless you’ve got hours to spare. I get why folks like the “no glycol” pitch, but in the real world, most installs just aren’t perfect—especially in older places or rentals where stuff gets tweaked over time.
Glycol’s not exactly maintenance-free, but if you’re managing multiple units or don’t want those midnight calls about cold showers, it’s the safer bet. I’ve had a few tenants try to “fix” things themselves and make it worse, but at least with glycol, you can usually walk them through checking pressure or spotting a leak over the phone.
Kits-wise, I’ve had decent luck with SunMaxx and Heliodyne for plug-and-play setups. Nothing fancy, but reliable. If you’re handy and want to save a few bucks, piecing together your own with decent pumps and a stainless heat exchanger works too. Just don’t cheap out on the expansion tank... learned that lesson the hard way when one failed mid-winter.
I hear you on the expansion tank—mine started leaking right after a cold snap, and it was a mess. I’m always a little nervous about glycol, though. How often do you end up testing or swapping it out? I’ve read it can get acidic over time, but maybe that’s just if you skimp on the good stuff. Also, any tips for insulating lines in crawlspaces? I’m paranoid about freezing.
I’m always a little nervous about glycol, though. How often do you end up testing or swapping it out? I’ve read it can get acidic over time, but maybe that’s just if you skimp on the good stuff.
Glycol’s a necessary evil in my book—especially if you’re running solar hot water in a climate with real winters. I test mine every fall with pH strips and a refractometer (cheap on Amazon). If the pH drops below 7 or the freeze point creeps up, I’ll flush and refill. The “good stuff” (like DowFrost) does last longer, but nothing’s forever. Two to three years is my usual interval, but I’ve pushed four with no problems when I was using higher-end glycol and topping up with distilled water.
About insulating lines in crawlspaces: I’ve tried a few methods, but thick foam pipe insulation (the closed-cell kind) seems to be the best bang for your buck. Tape all seams with foil tape to keep moisture out. In really cold zones, I add a layer of fiberglass wrap and then a vapor barrier—usually just 6-mil plastic sheeting. It looks overkill but keeps condensation down. For peace of mind, I’ve run heat tape on the most exposed sections, especially near vents or block walls. Just make sure it’s rated for potable lines if you’re doing domestic hot water.
One thing—if your crawlspace isn’t sealed or insulated itself, even the best pipe wrap won’t help much during deep freezes. Sealing up drafts and adding some rigid foam board along the foundation made a huge difference for me.
Curious if anyone’s tried those newer pre-insulated PEX lines? Saw them at the supply house last year but haven’t bit the bullet yet... they look pricey, but maybe worth it for tricky runs.
And yeah, expansion tanks—mine failed right after a cold snap too. Seems like they always pick the worst timing.
Pre-insulated PEX is tempting, but my wallet cries every time I look at the price tag. I’ve stuck with the old-school foam and tape routine, mostly because I’m cheap and stubborn. That said, I’ve heard from a buddy who swears by the pre-insulated stuff for long runs—claims it cut his heat loss way down and he hasn’t had a single freeze-up since. Maybe worth it if you’re running lines through a drafty crawlspace or outbuildings.
On glycol, I’ll admit I once tried to stretch it to five years... bad idea. Ended up with sludge and a bill from the plumber that made me rethink my life choices. Anyone else ever try those “glycol rejuvenator” additives? I’m skeptical, but maybe I’m just old-fashioned.
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Yeah, pre-insulated PEX is one of those things I keep eyeing too, but the price is rough. I’ve managed with foam and tape for years, and honestly, as long as you’re not running lines through an arctic wind tunnel, it does alright. But my neighbor did the pre-insulated for his barn and swears it made a difference in winter—his water actually stays hot.
On glycol, I learned the hard way too... tried to cheap out and ended up with a brown sludge mess. Haven’t tried those rejuvenators—always felt like one of those “miracle” car oil additives. I just swap mine out every couple years now and call it good. If there’s a greener alternative, I’d be all ears, but for now I just try to keep the system as clean as possible.