antifreeze in pipes
Is there a product that can be used in heating pipes. I heard that there is an antifreeze additive you can add to the system. I live in upststae New York, in a wind tunnel. My pipes are in my unheated crawl space, wrapped. Thanks for any help.
Re: antifreeze in pipes
Heating techs prefer to use antifreeze in heating systems only as a last resort.
The reason for the "last resort" concept is that there are often other things you can do to prevent frozen pipes, like added insulation, or rerouting the pipes thru a heated space, rather than a crawlspace, heating cables, or using constant circulation during bitter weather---all these options are lots better than getting into the hassle of ongoing antifreeze usage.
Antifreeze will bleed thru pinhole leaks, where ordinary water will not; if you lose water pressure you must have a backflow preventer on the boiler to prevent the AF from getting into your drinking supply; there's a 2-5% loss in heating efficiency using AF compared to water.
AF is $6-$10/gallon--depending on the amount of gallons in your heating system; you'll need 30% to 40%
antifreeze for adequate protection.
If you have 50 gal of water in your system X 40% = 20 gal. AF X $10 = $200.
If subsequent work is done on the system, any drained water needs more AF added at added expense.
If you've had problems in previous winters with frozen/burst pipes & you can't reroute the pipes, then antifreeze is probably indicated.
Nontoxic propylene glycol is sold by the gallon in heating supply houses as well as most HD/Lowe's stores--a backflow preventer should still be installed, as ingestion of this chemical, though non-toxic, is not recommended.
DO NOT use automotive antifreeze (ethylene glycol), which is toxic, and is NEVER used in heating systems---there's always the danger that the boiler water can mix with the drinking water under certain conditions--if the city water supply dept. does some work on the water supply in your area, you'll temporarily lose water pressure & the boiler water will back up into your drinking water if you don't have a backflow preventer ($40-$60 part cost + labor).
The easiest way to install AF is to shut off the boiler, drain as many gallons from the boiler drain as you need to put in, & use a plastic tube & funnel to put it in a removed bleed valve at the highest point in the system.
To calculate the amount, consult the boiler installation manual to determine how many gallons of water the boiler holds & add this to the contents of the rads & heating pipes.
From the raypak charts: 1 ft. of 3/4" copper pipe holds .025 gal of water; thus, 200' of 3/4" piping X .025 = 5 gal + 15 gal for typical boiler + 1 gal for each typical rad (15 rads) = 15 gal = 35 gal total system water X .40 = 14 gal propylene glycol needed.
Even a 20-25% solution is a lot better than nothing, and often makes the difference between freezing pipes and no problems at all, requiring much less amounts of AF.
A woman's electric hair dryer or a paint heat stripper is a good investment to have if a frozen pipe DOES occur---if this is in a copper pipe, it usually is on a supply or return to a rad, temporarily shutting down heat to only that one rad---the pipe will defrost by itself & heat in the rest of the house is not interrupted.
Last edited by NashuaTech; 11-09-2008 at 03:06 PM.