antifreeze in a home heating system

[MuskieJunkie]

At one of my rentals I have a hot water heating system, I would like to fill the tank and pipes with antifreeze rather than the strait water that is in there now.

Anybody have any thoughts on this, anyone ever do it, can somebody give me the 101 on how to do it? Thanks guys.

[Chad Halvorson]

50/50 mix, if its piped correctly (unlikely) you can pump it into the system and at the same time purge all of the air out at the same time. You will need a pump obviously, to do this. If you do not get all the air out, your pump could get dry (the pump in the system) and go out on you.

All systems (non Potable, obviously)should have glycol in them, not just to prevent freezing, but to lubricate the system and prevent corrosion.

Good Luck!

Oh also it will need to be around 15-18 psi (cold) when you are done, on most systems...

[Fishpondc]

if you do that, you'll need an rpz to meet code if the boiler is connected at all to the potable water according to mn code. if you have an rpz, you have to have it certified once a year and rebuilt every 5 by a licensed plumber

[UPnorthFISHING]

I have a out door wood boiler and when i installed it they told me not to put any antifreeze in the system... they told me it would reduce the efficiency of the water to carry the heat and transfer the heat in the stove..

[papabear]

if youare afraid of loosing powwer and having the pipes freeze then add glycol. Otherwise it may not be needed. In a rental unit where you are not present Id say add it. youll need to pwer purge the system so make sure it has the necesary boiler drains to add water and allow air to escape.

[Chad Halvorson]

 Originally Posted By: UPnorthFISHING

I have a out door wood boiler and when i installed it they told me not to put any antifreeze in the system... they told me it would reduce the efficiency of the water to carry the heat and transfer the heat in the stove..

If your system goes down for a few days with that setup, you will be replacing pipes. Adding glycol might reduce the efficiency (heat transfer), by VERY little if any IMO. However not adding it will cause problems, eventually.

[MuskieJunkie]

Thanks for all the good info guys.

 Originally Posted By: Chad Halvorson

if its piped correctly (unlikely)

You hit the nail on the head with that one! The run goes up to the 2nd floor then down, then up, then down again, multiple zone valves..... it's an air bubbles dream. I've had a lot of problems with this one (reason for the post) a heating contractor told me the best way to fix the system would be with a bulldozer (I think I have put that guys kids through college).

The thing I am stuggling with in the mechanics of getting the glycol into the system that is already filled with pressurized water. I do have a pump on the system.

[Chad Halvorson]

The pump that is piped into the system isnt what you will use to put glycol into the system, you will need an external pump. They are not cheap either, expect to pay around $150 for a quality one. Good Luck!

Basically you need a boiler drain, then a shutoff, then another boiler drain. You pump the mix into one side, with that shutoff "shut", and the other drain open with a hose going into a bucket.As you pump the mix into the system, the air is all removed into that bucket, and of course its filling with the mix. Just have your supply hose in that bucket, keep pumping until all the air is out. To get your pressure up, simply close that boiler drain off. Careful as it will rise fast, could blow the relief, and they dont like closing again.

[backlash 1]

This may or may not be a DIY job, depending on several things. Knowing plumbing, chances are it is not set up properly, and I would recomend hiring a professional to do the job. They are prepared to do the job properly, and know how to handle the WHAT IFS. Probably save a lot of frustration. Good luck.

[fishermn]

Well, a number of things come to mind with this. First off, I believe in an application like this, Propylene Glycol is probably what you would need to use, and you would definitely have to check into how to deal with makeup water, as you need to take special precautions when connecting the makeup water so as not to get any backflow into the potable water supply.

Yes, you will drop the heat capacity somewhat, but only by roughly 15% which probably will not be noticeable. The draining and refilling could take some effort... I havent done it, but maybe pressurizing with with air could be used to drive the remaining water out?

I would definitely talk with someone who has experience with this specific application, as there are probably a number of other things that need to be dealt with as well. Good Luck!

[bowhunter54]

I have not done this my self but have helped a heating guy install anti freeze in my system. So I will try to sum it up as best I can; I know Menards carries the product you need, it costs around $50 - $60 for a 5 gallon container. It has a scale on the pail as to how much is needed depending on the diameter and length of piping in your system. If you just have water in the system now I would just open the drain on the bottom of the boiler and drain out as much as the system will dump. Look at the chart on the pail it will tell you the percentage of material that is needed to protect the pipes from bursting. So what I am trying to say is if you have 10 gallons in your system and are able to drain only 5 you could then add the full 5 gallons from the pail to achieve a 50% mixture.

Find your self a small pump either a hand or an electric will work. You will need three short sections of garden hose. Connect one to the suction end of the pump dropping the other end into the 5 gallon pail of antifreeze. Connect another short hose to the pressure side of the pump and the other end to the botom of the boiler drain leaving the valve open. Connect another hose to the hydrant near the zone valve and the other end drains back into your 5 gallon pail of antifreeze. Start the pump watch the pressure gauge. As soon as pressure begins to build open up the zone valve to allow the antifreeze to begin circulating. This process allows the you to drive as much air out while filling the system. Keep the pump running to drive as much of the air out as possible. Close both valves and remove the pump and hoses. Start the boiler and run for a period of time while opening some of the bleeders to remove any excess air. You may have to repeat this process again as there wil be more air that will be driven off by the heating of the fresh water and antifreeze that was added. Hope this helps and I haven't made you more confused.