Will water freeze in a system if the circulator is on all the ti

Bruce

Does anyone know if water will freeze in a constant circulating system. You know how water won't freeze in the tap if you leave it running.

Pat

Actually, moving water (like the waterfall in this photo) can freeze. But it has to be a lot colder to do it.



To understand this, you can think about the way water freezes. When the water changes from a liquid to a solid, it starts in just one place, with just a couple of water molecules getting stuck together (because they're cold and not moving around very quickly). Then another molecule sticks to the first two. And another one sticks to those three, and soon you end up with a huge ice crystal that just keeps getting bigger and bigger as more water freezes onto it.

In order for the first two water molecules to stick together, they have to be pretty close together and not move away from each other. If the water is standing still, this is pretty easy - as the temperature drops, the molecules stop moving around as much, and they start sticking together. But if the water is moving, like in a waterfall, the molecules are more likely to move away from each other and less likely to get stuck together. So the temperature has to get a lot lower in order for the first ice crystals to form. But once you've got the first few, the rest will freeze more easily.

This is why they say that you should run the water in your sink (just a little) if it gets really cold outside. If the water is running, then it's moving through the pipes instead of sitting still. (Also, the moving water will provide some heat that will also help prevent freezing).

Pat

moving water can freeze

Actually, moving water can freeze. But it has to be a lot colder to do it. To understand this, you can think about the way water freezes. When the water changes from a liquid to a solid, it starts in just one place, with just a couple of water molecules getting stuck together (because they're cold and not moving around very quickly). Then another molecule sticks to the first two. And another one sticks to those three, and soon you end up with a huge ice crystal that just keeps getting bigger and bigger as more water freezes onto it. In order for the first two water molecules to stick together, they have to be pretty close together and not move away from each other. If the water is standing still, this is pretty easy - as the temperature drops, the molecules stop moving around as much, and they start sticking together. But if the water is moving, like in a waterfall, the molecules are more likely to move away from each other and less likely to get stuck together. So the temperature has to get a lot lower in order for the first ice crystals to form. But once you've got the first few, the rest will freeze more easily. This is why they say that you should run the water in your sink (just a little) if it gets really cold outside. If the water is running, then it's moving through the pipes instead of sitting still. (Also, the moving water will provide some heat that will also help prevent freezing).

PJO

The classic answer...

it depends! Water will freeze if it's moving slow enough, and the ambient temperature is low enough...look at a river up north in January. In the real world of hydronics, if you're worried about freezing, then it's going to have to be real cold inside (where the system is).

If it's truly a concern, put in the glycol solution and stop worrying.

Hope this helps, PJO

Joel_3

solid water

I had a friend try leaving the water on in his his ski/snowmobile house. Big mistake, furnace died when it was 0-30 bellow for a week. First the drains where the water goes real slow filled up and blew apart. Then after that all the supply piping too. not a pretty sight. iguess if your home it would be fine but I wouldn't try it in a place I left vacant.

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Aidan (UK)

Yes it can freeze.

The water is less likely to freeze, if the tap is dripping, because more water, at a temperature above freezing, is entering the system. The water will freeze first at the pipe walls and the ice will eventually block the pipe. I know someone who tried leaving a tap dripping, but their pipes still froze.

The pump will put some energy into the system and will circulate water from warmer areas to areas of high heat loss. However, if it's cold enough, the pipes can still freeze.

The only way to ensure it won't freeze is anti-freeze, trace heating or a frost protection device to fire a boiler.

Unknown

The police called

me to a house that had water coming out over the windowsills in the winter. It even had a full basement. It had a skimcoat of ice on it.

I called the electric company to pull the meter and stop the pump. There really was no longer a reason to hurry.

It was overwhelming to look at....Shut the valve when you go away. Plan for no heat.

Dana Zaichkin

Water in motion

Water in any state of motion can freeze if it looses enough heat energy to make the liquid/solid transition. Moving water can slow the freezing process in a couple ways. One, it circulates and comingles molecules with higher energy with those of lower energy - simply the water from the well or main is "warmer" than that in the exposed pipes. Second water in motion helps keep other minerals/salts/carbons and contaminants that can lower the freezing point in "solution".

Some of you might recall several years ago when a couple of wayward gray whales got "stuck" in a freezing arctic icepack - because they happened to be where some humans could find them, an enormous amount of resources were expended to rescue them - including a Soviet icebreaker, etc. One of the stopgap measures used were to bring some agitator/circulating pumps from some Great Lakes area marinas that kept the water in motion around the "holes" they were trying to maintain. Both of the factors mentioned above apply to this situation.

Best Regards

DZ

Tom Anderson

3 FPS

Water will not freeze if the velocity is 3 feet per second or greater and the fluid temp is 32F or greater. The 3 FPS is the key, determined through testing by Aerofin (sp??) in the 1930's.

Patrick

water freeze

Be sure that you have enough glycol in the solution to ensure protection. Depending on area of country and temps "burst protection" may be enough, will let system slush up but no damage will occur. You can get it in full strength to add to existing system, or if system is drained you can get it premixed to the spec you want. DO NOT USE auto antifreeze, will end up coating the inside of your system and will in turn lower the heat exchange, like a dirty coil.

Steve Ebels

Hard water problems

I can say for a fact that water at any velocity will freeze if conditions (ambient temp) is low enough. There is an old hydro dam on the river here where the water drops about 20 feet verticaly at an angle of roughly 50 degrees. When I was a young buck we had a stretch of weather where the temp went to -20 to -30 and reached maybe +5 during the day for a week. The "falls" froze completely over the entire width of the dam, about 45 feet. I, among others whose sanity was later called to question, walked over the cascade on top of the ice. You could hear the water still running underneath the ice but it was frozen to about 5-6" thick.

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