What Type Antifreeze for Radiant Floor System?

[59ctd]

I have a self made radiant floor system that uses a small Takagi water heater for the heat source. Installed in 2006 and running without issue since then every winter 24x7 @ 66*. It has a mix of distilled water and auto antifreeze in it now for probably 8 years and I really think it needs to be changed out to new antifreeze - probably past due now. Couple questions...

* What type of antifreeze is best to use in a radiant floor system? I know that the additives in auto coolant are not needed nor desirable in these types of systems.
* Recommendations on where to source said antifreeze?

 

[2011laramie]

http://www.chemfax.com/default.aspx?pageid=1155

This is the local supply here in central alberta.

 

[Firebrick43]

You need a polypropylene glycol. Make sure you flush your car antifreeze out well (ethylene glycol) as they are not compatable.

https://www.supplyhouse.com/Anti-Freeze-18370000

Supply house has great service and prices. I personally have Nofreeze by utility in my garage but to be honest I have no experience whatsoever with other brands.

 

[Jim greengo]

How is the system fed with water?

 

[lummino.plumbing]

Cryo tek

 

[metaleltr]

Based on the propylene glycol recommendations- rv antifreeze would be easier to get your hands on

 

[finn]

Menards sells propylene glycol with the proper addictive package in five gallon buckets.

Use the stuff designed for radiant systems rather than home brew, might work alternatives just because they are cheaper.

 

[59ctd]

Menards sells propylene glycol with the proper addictive package in five gallon buckets.

Use the stuff designed for radiant systems rather than home brew, might work alternatives just because they are cheaper.

Awesome and thanks! I did not know that Menards carries the proper fluid but it totally makes sense since they sell the radiant floor pumps and other related supplies. Looks like I probably want the Cryo-Tek AG propylene glycol product as it has the best freeze protection and can be mixed down to the freeze point desired. I should probably flush and/or clean the system out when doing the switchover. Is power flushing it with a garden hose hooked up to it sufficient or do I want hot/warm water for flush and maybe some type of cleaner to circulate in it for a bit and then a final flush with clean water?

 

[finn]

It’s usually along the side wall, near the pex tubing and water heaters if your local Menards has one of the standard Store layouts.

 

[u3b3rg33k]

I have a self made radiant floor system that uses a small Takagi water heater for the heat source. Installed in 2006 and running without issue since then every winter 24x7 @ 66*. It has a mix of distilled water and auto antifreeze in it now for probably 8 years and I really think it needs to be changed out to new antifreeze - probably past due now. Couple questions...

* What type of antifreeze is best to use in a radiant floor system? I know that the additives in auto coolant are not needed nor desirable in these types of systems.
* Recommendations on where to source said antifreeze?

instead of going through the trouble of changing all the fluid out, why don't you send off a sample for analysis instead?

 

[Jim greengo]

So,is your system hooked to your water supply to refill it?

 

[finn]

instead of going through the trouble of changing all the fluid out, why don't you send off a sample for analysis instead?

Automotive ethylene glycol antifreeze isn’t recommended for radiant heating systems. It often contains silicates which aren’t compatible with the Taco pumps and can come out of suspension, from what I remember.

 

[59ctd]

How is the system fed with water?

It is a closed loop system.

 

[59ctd]

instead of going through the trouble of changing all the fluid out, why don't you send off a sample for analysis instead?

Yea, thought about that or getting a pH tester but since it is not quite the right stuff and 8 years old now I'll flush and refill it with the proper stuff.

 

[Showkey]

Automotive ethylene glycol antifreeze isn’t recommended for radiant heating systems. It often contains silicates which aren’t compatible with the Taco pumps and can come out of suspension, from what I remember.

Also...........Silicates are well known to damage the pump seals.

 

[59ctd]

Also...........Silicates are well known to damage the pump seals.

Where would one typically see a leak issue from if this occurs so I can keep an eye out for any issues? I have a Grundfos brand pump and it has had ethylene glycol in it for ~13 years.

 

[finn]

The pump probably has a weep hole near the shaft seal.

 

[PCustoms]

Where are you going to dump all this contaminated water?

Please don't kill any pets or put it down the drain to cause other evironmental issues.

 

[Fix Until Broke]

If it's not broken...don't imitate my screen name

Friend of mine has had automotive anti-freeze in for over 10 years now, no issues - and it sounds like you don't either at this point. He was able to buy a 55 gallon drum of antifreeze for like 20% of the cost of what Menards wants for that much of the special stuff. We used distilled water for the balance (10k square foot, lots of tubes!).

 

[finn]

If it's not broken...don't imitate my screen name

Friend of mine has had automotive anti-freeze in for over 10 years now, no issues - and it sounds like you don't either at this point. He was able to buy a 55 gallon drum of antifreeze for like 20% of the cost of what Menards wants for that much of the special stuff. We used distilled water for the balance (10k square foot, lots of tubes!).

Biggest issue is probably toxicity of ethylene glycol a/f. It’s illegal for domestic heating in many jurisdictions, and has to be treated as a toxic waste for disposal of over 55 gallons (probably less some places)

Don’t dump it on the ground or in the septic system, especially if you have a well or septic. Some oil change places will take it for recycling, and small quantities can be handled by municipal sanitary , but not storm sewage systems, if it’s legal locally.

The silicates issue with water pumps is real. Note that Heavy Duty engines, ie Diesels, don’t have silicates in their specified coolants, for a reason.

Everybody has an uncle Moe who does stupid stuff and never seems to suffer from the consequences, and being a cheap *** to save a few bucks is short sighted.

 

[59ctd]

How is the system fed with water?

It is a closed loop system so it is manually filled with a small pump from a bucket of water or antifreeze when being serviced.

 

[Bills Tools]

I have a self made radiant floor system that uses a small Takagi water heater for the heat source. Installed in 2006 and running without issue since then every winter 24x7 @ 66*. It has a mix of distilled water and auto antifreeze in it now for probably 8 years and I really think it needs to be changed out to new antifreeze - probably past due now. Couple questions...



* What type of antifreeze is best to use in a radiant floor system? I know that the additives in auto coolant are not needed nor desirable in these types of systems.

* Recommendations on where to source said antifreeze?

I use propelling glycol and use a refractometer to check the mixture on the snowmelt systems I maintain. Ethalyn glycol has caused restrictions in heat exchangers. So purged all the water out of your system into buckets. Then with the system full of water get a 5 gallon jug and run your pump and mix the water and glycol into the system. Depending where you are you will want a -20 mixture.i have added 15-40 gallons of glycol to some chilled water systems.


Sent from my iPad using The Garage Journal mobile app

 

[bohalrantipol]

How much would you estimate is in your system? My local disposal place has a restriction on volume so I could only assume it may be a PITA to get rid of. Especially considering you should also capture the wash out.

 

[59ctd]

It is probably between 4 and 5 gallons.

Quite a few years ago I called our city water department and they said it is alright to dump small quantities of ethylene glycol in the sanitary sewer. That was >20 years ago so I should probably ask them again though.

 

[B.C.Biker]

If the problem is only with the silica then silica free type automotive should be fine if that's what you have in there? That type is fairly common
around here at least . Then test and no need to change/dispose.

 

[59ctd]

If the problem is only with the silica then silica free type automotive should be fine if that's what you have in there? That type is fairly common
around here at least . Then test and no need to change/dispose.[/QUOTE

I had used the normal auto antifreeze not the silica free type like my newer vehicles now take.

My son and I just picked up some Cryo-Tek -100 in a 5 gal pail at Menards. Looks like it is diluted a bit compared to the Cryo-Tek AG version. Still, -70f freeze point is more than low enough. I hope it never gets that cold!!!

 

[leeklm]

Have not posted here for quite some time, but wanted to share a recent experience using automotive antifreeze/distilled water in my 1200 ft shop in floor heat. I have not touched the system since installed 13 years ago. With all the warnings against using ethylene glycol, I was afraid of finding a mess when flushing the system. Quite the opposite. Fluid looked new and still tested to -35f. Virtually no sediment when draining the hot water heater. System is in MN so does see plenty of use 6 months out of the year. When first going this route, my reasoning was that if it can work in a car engine for years in contact with cast iron, aluminum, copper/brass, plastic, rubber, not to mention a more extreme environment... why not my floor??

Anyway, all the warnings to not use ethylene had me concerned, so I did now flush the system and spent the $600 on Cryo Tek 100 to do it "right". I am not advocating the use of ethylene glycol, but only sharing my experience. Maybe I got lucky? Experiment at your own risk...

 

[fitter30]

DO NOT USE ANYTHING FOR AUTOMOTIVE. Boiler/ chilled water only. There are two charts for protection. Freeze and slush both will give you what you want. Any brand 30% is minimum for the additive package and 50% is the maximum. The more % the arder it is to pump. For the slush chart if not listed call manufacturer tech line.

 

[59ctd]

Have not posted here for quite some time, but wanted to share a recent experience using automotive antifreeze/distilled water in my 1200 ft shop in floor heat. I have not touched the system since installed 13 years ago. With all the warnings against using ethylene glycol, I was afraid of finding a mess when flushing the system. Quite the opposite. Fluid looked new and still tested to -35f. Virtually no sediment when draining the hot water heater. System is in MN so does see plenty of use 6 months out of the year. When first going this route, my reasoning was that if it can work in a car engine for years in contact with cast iron, aluminum, copper/brass, plastic, rubber, not to mention a more extreme environment... why not my floor??

Anyway, all the warnings to not use ethylene had me concerned, so I did now flush the system and spent the $600 on Cryo Tek 100 to do it "right". I am not advocating the use of ethylene glycol, but only sharing my experience. Maybe I got lucky? Experiment at your own risk...

I also used auto antifreeze and water for the first 5 or 6 years when I setup my shop heater in 2006. It worked fine and there was no downside I could discern. Been using ~75% cryotek and 25% distilled water for the past dozen years without issue. This year is a major rebuild to replace my circulator pump and tankless heater and I hope to have it up in the next day or two.