Baseboard heat pipes freezing.

Mark42

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I have baseboard heating in my home. One zone tends to freeze where the pipe runs through a raised fireplace hearth. This usually happens when the outside temps reach single digits (like last night it was 4*). <br /><br />I want to add some antifreeze to the system, but have never dealt with antifreeze in a heater before. I figure there are about 600 feet of 3/4 copper pipe (including finned) on 4 zones. The boiler is oil fired with "tankless" coil for hot tap water.<br /><br />I have these questions:<br /><br />- How do I calculate how much antifreeze to use?<br /><br />- What is the best method of adding it? <br /><br />- Will antifreeze noticeably reduce the heating efficiency?<br /><br />Thanks,<br /><br />Mark
 

Bondo

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Re: Baseboard heat pipes freezing.

How do I calculate how much antifreeze to use?
You'll need to calulate the Gallons in the System.........(mathematician I'm Not) <br />You'll want a nearly 50/50 mix......<br />
What is the best method of adding it?
I did it with a Barrel Pump that had a "Hose" thread on the end of the spout......<br />A washing machine connecting hose to connect the pump to the Drain Faucet on the Boiler(Female connectors on Both ends)........<br /><br />Drain the system down.... pump the antifreeze from it's 5gal. pails Into the drain...... <br />Then close it up,+ allow the automatic pressure feed valve to "Top-off" the system.....<br />'Course, You'll still have to bleed the air vents in the Whole House........<br />
Will antifreeze noticeably reduce the heating efficiency?
Not at All.......<br />It's Still water..... it just Doesn't Freeze...........<br /><br />Does your car Overheat, just because you added New Antifreeze ??????<br /><br />BTW, I'm Not a HVAC Tech.......... Just a "Master Jack".......... :D
 

Mark42

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Re: Baseboard heat pipes freezing.

Thanks Bondo!<br /><br />Especially for the pump info. Right now I have a fire going to try to warm up the hearth to thaw out the pipe. Tried heating it from each end with propane torch, but after two hours it is still frozen. Making a fire has worked in the past, but it is still only 6* outside, so this will be a struggle.<br /><br />Mark.
 

Elk Chaser

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Re: Baseboard heat pipes freezing.

You have got to find the source of the air infiltration and seal it off. You can use expanding foam to seal it off if you can find the source of the air flow. <br /><br />There is a small possibility that the domestic water can get contaiminated with the glycol, all it will take is a pin hole in the coil and you would never know that you are slowly poisoning the family. I personally would not add glycol to the system.<br /><br />That would be my first plan of attack, fix the source of the problem first.<br /><br />20+ years of experience in the industry.
 

Mark42

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Re: Baseboard heat pipes freezing.

Hi Elk,<br /><br />I would not be using regular auto anti-freeze, the plumbing supply carries an anti-freeze that is safe to use in boilers that have hot water coils.<br /><br />The problem with the pipe freezing is that the pipe runs against an outside wall and also passes through a raised hearth that is 1' x2' x 8' . That puts about 16 cu ft of masonry between the pipe and the inside temperature, but only 6" of house wall between the pipe and the outside. Just a really bad place to run a baseboard heat feed. The pipe has foam insulation on it before it was encased in masonry. I will try snaking a pipe wrap heat wire along side it for now. I have to add another zone for the basement project I have going now, after purging the system for the new zone, I'll add the antifreeze. <br /><br />Thanks,<br />Mark.
 

radar750

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Re: Baseboard heat pipes freezing.

Mark, yes you can add antifreeze but it has to be non-toxic. You cannot add auto antifreeze.The reason is that is is corrosive to gaskets and if it ever did make its way into your domestic water supply you would be in a mess. You dont need to worry about it comming through your coil. If you did have a pin hole leak the domestic water pressure is so much higher than your boiler pressure that water cant flow from a lesser pressure to a higher one. You do however need a backflow preventer on your boiler supply. Only if you had a major pressure drop say from a water main breaking would there be a chance for boiler water to enter the domestic piping, thats what the backflow preventer is for. I suspose if you had a pinhole in the coil it could leak back if the water main burst. A pump is the best way to get it in, with out knowing what you have 10-15 gal will most likely do it. In a perfect world you would add it gradually and test it till you have the amount you want, they have test strips that tell you what temp you are good for.
 

Mark42

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Re: Baseboard heat pipes freezing.

Temps went up into the high 40's today and the pipe thawed out. I have changed the programable thermostat for this room to keep it warmer than the rest of the house by 3 degrees at all times. Hopefully that will keep the system from freezing until I get some antifreeze in there.
 

Bob_VT

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Re: Baseboard heat pipes freezing.

Well the R value of rock, cement or masonary is nearly non exsistant! If you can insulate the pipe in that space and close off all minute drafts you will win. A pencil size hole or crack in a wall near a pipe will freeze it right up. Remember from science class that hot water freezes faster then cold. Insulate it and you will win.<br /><br />Bob
 

BoatBuoy

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Re: Baseboard heat pipes freezing.

Urban legend - hot water freezes faster than cold.
 

flashback

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Re: Baseboard heat pipes freezing.

Im with you boat buoy, it is physically impossible for hot water to freeze faster than cold. Einstein probably turned over in his grave when he heard that one.... in any case, Mark, use a hydrometer to check to see if you have enough antifreeze in the system, it should work..
 

Mark42

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Re: Baseboard heat pipes freezing.

Just a quick update... Found I have an old submersable pump that has a garden hose thread on the output side. Also found a new cloths washer hose in the basement, so the double female hose will connect the male pump to the male spigot on the furnance. I figure to fill a 5 gallon bucket with antifreez, drop in the pump in it and let it pump the antifreeze in one zone at a time until I have 5 gallons of anitfreeze or protection to -20 on my tester. <br /><br />Wish me luck!<br /><br />Mark
 

flashback

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Re: Baseboard heat pipes freezing.

sounds like a good plan Mark, just turn the system on and it should do all the mixing for you....Hava a warm Christmas :)
 

Ben Konopacky

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Re: Baseboard heat pipes freezing.

mark; " IF " you do put glycol into your sys.as a precaution install a back flow preventer (stops the flow from going back into the main h2o supply)most plumbing codes req. this today reguardless.
 

Bondo

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Re: Baseboard heat pipes freezing.

My system took 15 gallons........<br />5 doesn't sound like enough......
 

Mark42

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Re: Baseboard heat pipes freezing.

Added the antifreeze today. Went real smooth. No problems. Put a pump in a 5 gallon bucket and filled with antifreeze, shut off the water feed and let some pressure off the system. Then pumped in a total of 6 gallons of antifreeze. Will probably add another 4 gallons, but this means that I will have to loose 4 gallons of mixed freeze from the system to fit it in. <br /><br />I did notice that with all 4 zones open (manually), the circulator motor just couldn't push water through all zones at once. One of the circuits was not getting any circulation to speak of. But rarely if ever are all 4 zones operating at once, so I never noticed that one area of the house was cold. <br /><br />I will be adding another zone as part of the basement finishing project. (more antifreeze!) At that time, I will add a second circulator and split the zones between the two circulators. I looked at the control box and it has connections/relay switches for two circulator motors, so I should be OK. Will probably need another 40va transformer as well. Probably taxing the existing one with 4 Taco zone valves (570 model). <br /><br />I don't know why some folks don't like the Taco products. My house is 14 years old and none of the Taco products has ever failed. Keeping my fingers crossed!!!
 

Paul Moir

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Re: Baseboard heat pipes freezing.

Four is usually the limit for one 20VA transformer. Add up the current consumption of all your zone valves and multiply by 24 to get your VA. They're usually around 0.33A each. You can run two transformers each running different banks of zone valves.<br /><br />You can also wire two transformers together in parallel to make a 40VA one if you get the phases right. But they've got to be identical. And the only reason to do it is to make your wiring neater and to freak out the furnace techs.
 
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Re: Baseboard heat pipes freezing.

You shouldn't install more glycol than protection to -23C. Beyond that you will make the heating fluid too "heavy" & will have to rengineer pumps etc. One trick you can do on that one problem zone is install a Honeywell non-freeze zone valve when you do your basement mods. It basically is nothing more than a small notch (bypass) that will allow heating fluid to slowly circulate at all times the pump is on. The idea is it allows fluid to move but not fast enough to create over heating condition.<br />I spent the last 30+ years installing,servicing hydronic heating in all its forms.
 

Mark42

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Re: Baseboard heat pipes freezing.

Hey Poppasmurf,<br /><br />I am thinking of installing a larger Taco 009 or 0011(1/8 hp) cirulator pump to replace the 007 (1/25 hp) model rather than add a second 007 pump. <br /><br />My reasons are this: 1) I made a mistake when I said the control box has connections for two cirulators. I will need to add a new control box. Must have been thinking about my last house. 2) It will be less work to replace the pump with a higher volumn unit than to make the necessary plumbing changes to get two circulators going on separate zones. Plus will have to add another air scoop/vent to the new circulator.<br /><br />I calculate that right now I have about 600 feet of 3/4" copper divided up on 4 zones. The house was built with 2 zones, I isolated the family room to its own zone, then later added a new master br and bath on its own zone. I suspect that the Taco 007 circulator is not circulating the water fast enough on some zones when 3 zones are operating at once. I think the water is getting too cool by the end of the loop on the second floor causing one br to be colder than the others. Plus I will be adding another zone for the basement that will add another 100 feet of 3/4" copper to the system. <br /><br />Any suggestions?<br /><br />Thanks<br /><br />Mark.
 

fireship1

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Re: Baseboard heat pipes freezing.

Hello, The Taco 007 isn't going to cut it for all of those zones and all of that pipe. Papa is also correct. Adding glycol will make the circulator work harder and kill a bit of its efficiency. Water with glycol added is a bit more friction for the pump to pass. It's time to ditch the 007, go with a Bell and Gossett pump. They make larger models that will be able to handle the volume of your setup with no problem. I agree with you on the Taco products, however. I too have an 007 circulator and a set of Taco zone valves. All trouble free for many years. Good luck!
 
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