Cold climate guys, do you always antifreeze your hydronics?

CBRob

Been talking to a local master plumber and boiler guy who depending on the home, has no problem with an infloor heat system running straight water.

If the system piping is no exposed to any cold spots or exterior, is there any real reason to add the freeze protection. Is hydroponic piping any more vulnerable? The only factor I can see is the in slab tubing being an expensive repair, but would only come into play in an abandoned house were all the other piping would be frozen too. Your thoughts?

mattmia2

glycol is an only if you absolutely need it thing. it will corrode metal if not maintained, it attacks seals, it makes heat transfer significantly less efficient

rick in Alaska

Virtually no one has glycol in their heating systems here, but our climate is mostly mild. Fairbanks, not so much, so I am sure most are.
I have glycol in my own slab for my detached garage, but only because I have the heat off if I am not working in it. I would only advise my customers using glycol if it is a house that is not monitored when they are gone, but most of our snowbirds have someone watching the house when they are gone, or have some kind of alarm, so it is not an issue.
Rick

SuperTech

Hydroponic piping? Are you heating a greenhouse with radiant flooring? 😉

I always avoid glycol unless it's absolutely necessary, such as a hydro air unit in an attic.

GroundUp

It depends on the system. Anything besides a slab, never- unless the customer wants it or it's in a seasonal home that's left to freeze on occasion. However 95% of my business is radiant slabs, and if there is a garage attached to the system I will always use glycol. Every winter I get a couple dozen calls about no heat in the garage, always frozen loops. When it's a house slab only, then I typically leave it up to the customer but explain the options with them knowing there will be a little maintenance required but there will never be a freeze issue- the vast majority of them ask for glycol. I have had quite a few calls from new homeowners, after buying a home they discover the in-floor heat doesn't work. Well, the home was usually foreclosed or left vacant for an extended period of time and froze the loops resulting in burst tubing. So now they spent their life savings on their dream home, BECAUSE of the coveted in-floor heating, which now cannot be utilized without mass destruction of the home to repair the leaks. Glycol is cheap insurance in my opinion, and the minimal maintenance it takes to keep up is well worth the 3% lost efficiency and once-a-decade flush if it means the system will live a long prosperous life. It's -20F here as I type this, which is not an uncommon temperature in MN, so my theory may not apply to a lot of other areas but as far as radiant slabs go, I find it foolish to run straight water in this climate.

Henry

All our radiant is 50-50 glycol, geothermal and the same for snow melt. It is tested every 5 years. There are two types of which one is banne my our AHJ. Can't remember right now which one as I don't order it, the project manager orders it.

pecmsg

Henry said:

All our radiant is 50-50 glycol, geothermal and the same for snow melt. It is tested every 5 years. There are two types of which one is banne my our AHJ. Can't remember right now which one as I don't order it, the project manager orders it.

That's some serious freeze protection

Is -35°F really needed?

BobZmuda

Propolyne glycol is the safe one. Ethylene glycol is the one you do not want to drink.

I think many are overdoing it in their systems. A basement slab in MN will NEVER reach -35 degrees.

There is also a difference between -35 degree freeze protection and -35 degree burst protection. You can get greater heat transfer while still protecting the loop by figuring for burst protection instead of freeze protection. Fremont in Minnesota is a very good chemical distributor and has helped me out quite a bit.

I've had great results with figuring for burst protection in a chilled water/hot water loop. Part of the loop sits outside and not circulated during most of the winter. The water/glycol/inhibitor mixture is called to circulate when it gets to less than 0 outside. Two pumps are used, one as backup. Continuous circulation can be a nice added insurance against catastrophe.

Solid_Fuel_Man

I view glycol as a bandaid in most systems.

Foreclosures are just that: buy an abandoned home that has been "winterized" which means they put a few stickers on the toilets. Every pipe, boiler, radiator is split open somewhere. It's a foreclosure.....not a dream home, yet.

The tubing I put in garages, I keep back 24" minimum away from the overhead doors. I have yet to have a customer have a frozen garage slab. I did this in my own home as well, no antifreeze. The now still melts in front of the overhead doors. It would take a long time to freeze tubing in a slab. I'd argue much longer time than a copper fin-tube system to freeze. I also encourage homeowners to have me install fan-coil units as supplemental heat in a garage, most do.

But it is an insurance policy of sorts, just a messy and maintenance involved one. Every auto air vent turns green!

It been below zero for 2 weeks here.

GroundUp

@Solid_Fuel_Man every home is somebody's dream home, foreclosures included. I had one this fall, a $700k house with a 6 zone radiant slab on grade, that simply had a fried transformer while the owner was on vacation and allowed the slab to freeze and burst lines in 23 different locations throughout the house. The cost of a whole new forced air system was less than half of repairing the radiant, so they went that route. Sure, this could have been prevented with monitoring and an on-call electrician to repair the transformer- but it also could have been completely prevented with $400 worth of glycol.

If you're keeping your garage at 60 degrees and pulling the tubing back 24", sure it might be fine for a few days like that. The majority of people (here, at least) keep their garages at 40-45 which would amount to frosted edges and doors if the tubing were pulled back so far. Every one of my slabs gets a loop 6-8" from the outside edge which is necessary to prevent this problem with proper water temps. Last winter I had a gentleman with a 45 degree garage freeze all 4 loops shut because a pump failed while he was gone fishing for only 2 days. The slab surface temp didn't reach above 32 degrees until 9 feet from the outer edge, near the overhead doors. And yes the edge was insulated with R10 XPS, it was just -30F that weekend. Luckily nothing burst, I was able to get my thaw rig in there and thaw from the top down then flushed the system and filled with 30% PG.

If anyone can give a single example of properly maintained propylene glycol being detrimental to any hydronic system (aside from the miniscule heat transfer loss), I'm all ears. If your vents or any other component are turning green that's because they're leaking- water will do the same thing. There is no excuse not to use glycol in a cold climate radiant slab unless it's in a basement.

GroundUp

As for concentration, there's no reason to ever use 50/50 either unless for sheer laziness. Even my snowmelt systems only get 40% and have never not been pumpable at -40F ambient air temp. My sidewalk at home for example, is on the north side of my house and never sees the sun, ever. About a month ago it was -35F and WINDY here one night while also snowing. I flipped the switch and the circ whined a little, the lines actually frosted up in the basement, but I was melting snow in about an hour.

Canucker

> @pecmsg said:
> (Quote)
> That's some serious freeze protection
>
> Is -35°F really needed?

@Henry is in the Montreal area, if I'm not mistaken. I would consider it necessary

pecmsg

Freeze protection means ice crystals can form. The liquid becomes thicker but can still be pumped. how often will you see temperatures of the "Fluid"
With a 50 / 50 mixture the burst protection is what -65 or -70°F. Way overkill.

Canucker

No wind chill?

mattmia2

So what is the definition of "freeze protection", "pumpable" and "burst protection"? I think I can guess at burst protection, but especially "pumpable" seems a little dubious.

@Canucker wind chill only applies to things with moisture on them that can evaporate and take the latent heat of vaporization with it like skin.

EricPeterson

Here is Burnham's advice from their "I&O Manual" for the ES2 boiler:

• PROTECT YOUR HOME IN FREEZING WEATHER. A power outage, safety lockout, or component failure will prevent your boiler from lighting. In winter, your pipes may freeze and cause extensive property damage. If you must leave your home unattended for an extended time when outdoor temperatures are below 32°F, first turn off your home’s main water supply and drain the water from all pipes.
  

No mention of antifreeze.
Does anyone actually take their advice?
Note that I don't have a slab, just an old house with radiators in the Chicago area.
In the future I would like to be able to take some winter vacations, but not unless I feel comfortable that the heating system is not in danger. I can monitor from a distance but right now I have no one on call to be able to come and fix any problems that arise. Personally I do not want to go the antifreeze route - would prefer instead to have a local service outfit that I know and trust be available to deal with any situations that might come up. I would prefer someone familiar with Burnham products. I asked our A/C guy, but they don't do Burnham.

Solid_Fuel_Man

@GroundUp I didnt mean to sound objectionable. I'm from the economically depressed far north, and we have many foreclosures. The majority are not well taken care of and go for very little money.

I just dont like glycol due to its nature to make thinks leak. Every glycol job I see has lots of green crap everywhere due to no fluid maintenance.

GroundUp

Solid_Fuel_Man said:

@GroundUp I didnt mean to sound objectionable. I'm from the economically depressed far north, and we have many foreclosures. The majority are not well taken care of and go for very little money.



I just dont like glycol due to its nature to make thinks leak. Every glycol job I see has lots of green crap everywhere due to no fluid maintenance.

Nor did I, I know what you're saying. I buy a lot of foreclosures to flip or turn into rentals but there are a LOT of really nice homes that get foreclosed on here, many of which turn to junk during the process. The stuff I buy is all $50-100k "rental quality" property but there are a lot of $250-350k homes on the foreclosed market at all times. I have never seen a leak caused by glycol necessarily, but it does have a tendency to find poor joints that wouldn't leak with water. Again I know what you are saying, but from an insurance standpoint I see no reason to risk straight water when glycol in a closed system will often go 20 years without needing maintenance.

hot_rod

Freeze point= ice crystals form
Slush point= no longer pumpable
Burst point= freezes and expands

Green fuzz forms around a lot of glycol connections, press, threaded, compression

Some contractors use only copper sweat for glycol

nibs

Slightly OT
When we went south for a month at xmas we left a TemperatureStick in the house, head worry wart (moi) was able to see the hourly temp and could have called my gas fitter to visit in the event of a problem, I could see the boiler firing times, it was also set to email a message if house temp went below 37F.

EricPeterson

@Nibs - I too am a worry wart.
Do you mean this: TempStick?
And how can you see the boiler firing times?

GroundUp

The green fuzz does not form with a properly sealed joint. Glycol does tend to find those joints and make them obvious unlike water or air, but just because it doesn't leak water or air doesn't mean it's a good joint. With that said, I pressure test every system I do to 100psi with air for 12 hours minumum. All my residential systems are soldered copper. I have had a number of joints hold that 100psi of air for days, but show a leak within minutes of pumping in the glycol- that same joint would have never leaked with water but that's just the nature of glycol. I also have a number of 15+ year old glycol systems full of threaded connections that have never shown a hint of fuzz. Female adapters seem to always be the worst culprits in that department. After I discovered this fuzz problem I started using anaerobic sealant such as Permabond LH150 or Loctite 567 on all threaded joints in glycol systems and have all but eliminated the issue, aside from some female adapters for some reason.

nibs

@EricPeterson
The TempStick records the temp every hour (you can make it shorter as often as 10 Mins). If you put the sensor in a place that is warmed rapidly such as on a manifold, it will record cycle times, as temp changes.
I left mine on the thin slab radiant floor & could see the fluctuations. It would certainly indicate short cycling, without needing anyone on site.

Henry

In our area it is standard practice for 50/50 Poly. While the province I one of the largest producer of hydroelectricity, we have many power failures that can last a few days or a week. We can purchase large quantities of premixed 50/50 from a number of suppliers.

GroundUp

Henry said:

In our area it is standard practice for 50/50 Poly. While the province I one of the largest producer of hydroelectricity, we have many power failures that can last a few days or a week. We can purchase large quantities of premixed 50/50 from a number of suppliers.

Who sets this "standard"? 50% is unnecessary in even the harshest of conditions, much less a basement slab

pecmsg

GroundUp said:

Henry said:

In our area it is standard practice for 50/50 Poly. While the province I one of the largest producer of hydroelectricity, we have many power failures that can last a few days or a week. We can purchase large quantities of premixed 50/50 from a number of suppliers.

Who sets this "standard"? 50% is unnecessary in even the harshest of conditions, much less a basement slab

Possibly the same ones that still believe Bigger is Better!

mattmia2

GroundUp said:

Who sets this "standard"? 50% is unnecessary in even the harshest of conditions, much less a basement slab

The one that asked what "pumpable" means and didn't get enough of an answer to figure out if the head on the pump would go up to a point where the fluid wouldn't circulate or it would damage the pump

Tinman

I only use it for Snow and Ice melt systems. Here in the Chicago area, I can have my garage slab heat off for days when it's in the single digits and the slab temperature never drops below 59*F.

GroundUp

Steve Minnich said:

I only use it for Snow and Ice melt systems. Here in the Chicago area, I can have my garage slab heat off for days when it's in the single digits and the slab temperature never drops below 59*F.

How warm do you generally keep it in there? Most garages around here don't even have a 59 degree slab surface temp while they're being heated. I run my shop at 50 degree ambient air temp via radiant slab with 90* SWT and the surface temp never exceeds 65 but drops to 54-58 before the stat calls for heat again, depending on the weather outside. If it's 20 degrees the slab may only hit 58-60 before it's satisfied, if -20 outside it clicks out at 63-65.

Tinman

Its actually my shop. I keep it warmer because my dog likes to hang with me and lay on the concrete.

rick in Alaska

Steve Minnich said:

Its actually my shop. I keep it warmer because my dog likes to hang with me and lay on the concrete.

I love it! You don't keep your shop warm for your comfort, but for your dogs comfort. The sign of a good pet owner.
Rick

MikeL_2

To quote a favorite mentor, " it depends ". We'll only install antifreeze ( typically about 35% ) in systems that employ " pumping away ". I've never quite understood why ahu's are / were installed in attics, often 25 - 30 ' above the boiler? Why not install the ahu on the second floor of colonial style homes, and use a taller ( 9' ) ceiling height so duct systems can be hidden in soffits within the conditioned space?
We have several customers with weekend seasonal properties, and having hydronic systems with properly maintained antifreeze makes for fewer emergencies.
These folks can afford the extra work required to keep their systems fluid potent & balanced. And the more frequent service visits help with overall heating system maintenance.
As far as " fuzz " and blue / green leak trails, we deal with them as they occur and include these repairs as a part of antifreeze maintenance. I read somewhere that propylene glycol has a different surface tension than water and that's why it seeks / finds an escape where air or water won't ........

oak

What about us homeowners? We run and 50/50 glycol mix. How do I clean the corrosion?

I have a small house with 4 zones of wall-hung Eurostyle radiators, a 110,000 BTU TT tank in tank boiler plumbed with Pex through the outside walls. No basement or attic (insulated cathedral ceilings, and insulated floor). It's a windy location, design temp of -10. Where the Pex rounds corners it pushes to the outside through the cellulose and so is close to low temps. We travel a lot and I am well past retirement ... simply don't want any problems and even less worry. I have a lot of corrosion (copper, brass electrolysis I assume with a green blue fuzz). Every joint and fitting in the boiler and outside around manifold and circulators gets that fuzz build-up.

Jaberstein

Don't try this at home.
Being a young pipefitter and observing how the engineers designed hot water system, I designed and installed a custom wood and propane boiler system with radiant heat in the basement floor. It is located in PA woods where the building is left unheated until occupied. It originally had car antifreeze in it from 1976 until 2016 and never had a leak or a problem. In 2016 the car antifreeze was replace with ethylene glycol with the correct inhibitors for a copper and steel system.
I have entered the building when the fluid temperature was -10 degrees and warmed up the fluid with the boiler and wood boiler.
The radiant piping in the floor is all copper and sees water temperature as high as 160 degrees as well as the convectors on the1st and 2nd floor.
The only problem I ever had was during a power outage with a roaring fire in the 2nd floor wood boiler which looks like a Franklin stove I build out of 1/4" steel plate, the fluid due to lack of circulation turned to steam which in turn built up the system pressure and opened the relief valve on the basement boiler and drained out the fluid into a tank from the wood boiler as it is at the highest point in the system. At that point if becomes safe without fluid.
I am lucky that this system has worked all these years problem free, but considering that this was designed and built at such a young age 24 with no experience other than installing pipes for 5 years, I feel I am blessed.
I hope to get the next 30 years out of it problem free.

Zman

oak said:

What about us homeowners? We run and 50/50 glycol mix. How do I clean the corrosion?

I have a small house with 4 zones of wall-hung Eurostyle radiators, a 110,000 BTU TT tank in tank boiler plumbed with Pex through the outside walls. No basement or attic (insulated cathedral ceilings, and insulated floor). It's a windy location, design temp of -10. Where the Pex rounds corners it pushes to the outside through the cellulose and so is close to low temps. We travel a lot and I am well past retirement ... simply don't want any problems and even less worry. I have a lot of corrosion (copper, brass electrolysis I assume with a green blue fuzz). Every joint and fitting in the boiler and outside around manifold and circulators gets that fuzz build-up.

Leaks at every joint is not normal. What type of glycol? How are the joints connected?

schreib

Lots of great info from you folks here. The discussions here basically indicate that it is really NOT imperative that a 50/50 mix be used in hydronic heating. I appreciate the insight from various folks around the country.

I am a homeowner & mech. engineer-- GC'd this home and designed it: Lochinvar 55,000 Knight Boiler, slab on grade, including garage with hydronic heating. I have been trying for months to get in a contractor to adjust my PG from 50/50 down to 36% PG and add a separate pump to isolate the garage loops-- with no takers. Mainly want better heat transfer and see no need for 50/50-- excessive. I also want to put my garage loops(4) on a separate pump and keep it continuously circulating, only heating to keep it above 45°F in winter( have a propane unit heater for occasions I want to work there.) I have never turned on the T'stat and "run" the garage due to lack of attic insulation until last week. If I isolated the garage w/ separate pump($120) I would feel comfortable leaving it at 36% PG (optimum burst capability) . Does this plan sound UNreasonable??

I have been wondering if here in MN it sounds crazy and that is why I have no takers. Actually, just ONE so far: "I don't want the job price"!

Zman

I would be comfortable with 36% without constant circ unless the slab insulation is horrible or you intend to turn off the heat completely. 50% is for snowmelt systems only.

Zman

We don't talk pricing on this forum.

schreib

thanks I will edit the pricing stuff . . . appreciate input on 36%. WELL insulated --3" foam under and 2" foam on edges.

GroundUp

@schreib I responded to your PM, hopefully we can get this squared away

hot_rod

> @Jaberstein said:
> Don't try this at home.
> Being a young pipefitter and observing how the engineers designed hot water system, I designed and installed a custom wood and propane boiler system with radiant heat in the basement floor. It is located in PA woods where the building is left unheated until occupied. It originally had car antifreeze in it from 1976 until 2016 and never had a leak or a problem. In 2016 the car antifreeze was replace with ethylene glycol with the correct inhibitors for a copper and steel system.
> I have entered the building when the fluid temperature was -10 degrees and warmed up the fluid with the boiler and wood boiler.
> The radiant piping in the floor is all copper and sees water temperature as high as 160 degrees as well as the convectors on the1st and 2nd floor.
> The only problem I ever had was during a power outage with a roaring fire in the 2nd floor wood boiler which looks like a Franklin stove I build out of 1/4" steel plate, the fluid due to lack of circulation turned to steam which in turn built up the system pressure and opened the relief valve on the basement boiler and drained out the fluid into a tank from the wood boiler as it is at the highest point in the system. At that point if becomes safe without fluid.
> I am lucky that this system has worked all these years problem free, but considering that this was designed and built at such a young age 24 with no experience other than installing pipes for 5 years, I feel I am blessed.
> I hope to get the next 30 years out of it problem free.

EG ethylene glycol if fine as long as you do not have an indirect tank or any potential for cross contamination to the potable water.
It is common in large systems that are heat only