best glycol and mix for my boiler system?

clydesdale

I screwed up and had a failed expansion tank that was causing my PRV to leak. I allowed about 20 gallons to leak out over the past month. As a result, I diluted my glycol and it needs to be replaced. Cryotek 100 was recommended to me. Is this like a car where the mix will be 50%. How do I figure out how much I will need? I would consider doing the job myself if there are good videos on how to do it. Any help with this process or product is greatly appreciated. Thank you.

hot_rod

A few suggestions:

You do not want to blend different brands as they use different inhibitors that may not get along.

My process would be to squirt in a cleaner and run that for a day to get the system to a good starting point for new glycol. Flush it out well.

This system cleaner comes in a squirt can, screw it onto a purge or drain valve, hose thread, open valve, and pull trigger. Be sure it is tightly connected as the can empties in seconds!

Choose a glycol brand and the %. Most brands have info on the container for protection. Generally 30- 35% is adequate, but decide on the lowest temperature you want protection to.

This Fernox Alphi 11 at 35% will flow down to, -11°F burst at -40°F

You will need some way to pump it into the system and purge air out. A 5 gallon bucket or plastic garbage can allows you to pump out, and purge back int the bucket until you do not see or hear air bubbles. This can take some time depending on the piping, zones and amount of fluid.

Simple and inexpensive is a 5 gallon bucket with a small submersible type pump from the Home Stores, 1/2hp is plenty.

Or find pool or spa pump on Marketplace and build a system like this.

Some hydronic wholesalers have pump carts to rent or loan, that makes it a simple, safe job.

I would buy pre-mixed glycol and use it right out of the bucket. Then you have the correct blend.

You do not want a fill system connected that could add water and dilute the mix, as you have learned.

Some choose to add a glycol fill tank to add fluid as air bleeds out.

Glycol is very slow to give up entrained air, it may take days for a good air purger to get the system 100% air free. You will need to boost pressure up to 12 psi a few times as air slowly comes

clydesdale

That is a very helpful post. Thank you. I am considering doing this job myself and will certainly have additional questions.

Cryo Tek 100 was the product that was suggested by a local boiler guy. I am fine with idea of buying concentrate and then simply mixing it with distilled water. My understanding is that will be a little more cost effective. The guy had suggested mixing it at 50%. I live in NY and rarely we get temps down to zero or subzero. There are plenty of single digit nights. But, according to the charts, 50% mix might be a little over kill. Aside from cost, are there additional negatives to higher concentration?

Everybody that hears I have glycol in the system tells me how bad the glycol is for all my system parts, but they know I have no choice as I have an air handler and coil in an unheated attic.

My brother is going to help me calculate how much we might need. I believe we need to calculate the linear feet of pipe. Then we have to figure out how much the boiler and 2 coils hold. One guy thought I might need 20 gallons of concentrate, so 40 gallons of total mix. That just sounds like a lot to me.

ScottSecor

@clydesdale in simple terms, antifreeze reduces the heat output. For example, you may get away with 150 degree water and heat your home on the coldest night. Add thirty percent glycol mix and you might need 170 degrees.. Add fifty percent glycol mix and you might need 190 degrees.

In addition the fluid does not flow as well when antifreeze is added. You may need a slightly larger circulator.

For these reasons and cost you don't want to use more glycol/antifreeze than you actually need. One method to determine the capacity of a relatively small system is to fill the system with water and vent all of the air out. Then drain the system into empty five gallon buckets.

clydesdale

Will this product work the same as F3? Supplyhouse is where I often order from. Thank you.

X800RD - Sentinel X800RD - Sentinel X800 Fast Acting Cleaner Rapid-Dose

clydesdale

How do you introduce the cleaners that don't screw onto a drain and get shot in?

Also, I don't think I am going to go with the auto feed system this time. But, I would love to know more about them. At this moment, I need to simply make the system safe from freezing and enjoy the holidays. I can then research this another time and when I replace my attic air handler in the next couple of years, I will then consider this upgrade? What is the need for this expensive device if the house has been fine without it for 27 years? Thanks.

Just a crazy thought. Could I drain the upstairs heating system in the unconditioned attic while I am away for 2 weeks in the winter and not put glycol in the system? Just simply drain that loop? I realize I would not have heat in that loop, but wouldn't that make it safe or am I totally off base? Thanks.

EBEBRATT-Ed

@clydesdale I live in MA where our design temp is 0 deg. We occasionally see-5—10 maybe 2-3 timeas a winter. We used 30% glycol with water and never froze anything up. Even equipment that was outdoors. Two much is harder to pump and slows heat transfer. Freezing point and bursting point is two different things. It may get slushy thats about it

hot_rod

you could drain the part of the system prone to freeze. You would need two valves to isolate that section then repressurize the balance of the system. to keep it going

Any brand of cleaner will work, Fernox, Rhomar, Axiom, sentinel

If you don’t use an aerosol can you will need to pump it in.

The nice people here that do this for a living are suggesting 30-35% why would you want to go 50%?

clydesdale

I am absolutely going to listen to the nice people here. They guy I spoke with said 50% and so far his is the only guy suggesting that. Why would I want a higher concentration of the expensive stuff that beats the crap out of the system? I don't. I am also considering pumping the stuff in myself with the help of my brother and the help of you guys.😁 Thank you so much!!!

Next step is I need to calculate how much to buy. Pointers?

pecmsg

Just get a 5 gal bucket straight glycol.

hot_rod

I would pump in 1 gallon of glycol, then 2 of water, keep doing it that way instead of pre blending too much if you don’t know the volume

As air vents out, fill with undiluted glycol to assure you keep the %
buy a refractometer and a stick type ph meter to check where you end up.

Check ph every couple years keep it in the range the manufacturer recommends, you can add a ph booster if needed

In a clean system with good fill water, 10, 15, or more years is a reasonable life