glycol for vacation home

pat_3

i installed a heating system in a customers primary daily residence a few years back(aprox.5000square ft. home 85%radiant 15%supplemental baseboard ) .the home will soon become a vacation residence ,in an area that gets more than a resonable amount of power outages.homeowner doesn't want to rely on backup generator for freeze up protection and would like system filled with glycol.i'm assuming all the circ pumps will need to be changed(all circs are b&g nrf22).Are there any other changes i need to consider?i'm not very familiar with the effects of glycol. any good books with reliable rules of thumb on the subject?any help is much apprieciated.

Duncan

Duncan

Glycol effects

Glycol is thicker than water, so the head is greater. Most systems are overpumped, but with the little NRFs, it may have some effect.

As for heat capacity, a 50% solution of glycol still carries 90% of the heat of water. Considering most systems are at least a little oversized, that's probably not an issue.

Count on fixing a few leaks the glycol will find.

Click on "Hot Tech Topics" on the pipe to the left of the wall's main screen. In the search box, type in antifreeze. It will help. Or go to:

http://www.paloma@raypak.com/afreeze.htm

hr

Pros and cons

You will be able to adequatly provide freeze protection, generally a 35% glycol mix will be adequate. 35% Dowfrost HD will provide a -30 F burst protection. With this mix your current pumps probably will be fine.

The system must be cleaned and flushed of the old fluid. A hydronic system cleaner is the best to remove old dirt and oils. Good quality blend water is very important. Blend water "out of spec" will deplete the inhibitor package from the get go.

Make sure to disconnect any automatic fill valves, and add a good LWC control in event of a leak down. Check with the boiler manufacture as some have a limit to the glycol percentage allowed.

Buy a good brand of glycol inhibited for hydronic applications. I like DowFrost HD. Get a free copy of Dows Engineering guide on DowFrost by calling 1-800-447-4369.

You will want to preform a yearly check up on the condition of the fluid. Dow also has kits for this.

How will you protect the hot and cold domestic plumbing?

hot rod

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pat_3

glycol /vacation home

domestic hot and cold will be drained down.thanks for the advice guys