Draining the boiler (furnace) for service

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  #1  
Old 06-25-19, 05:18 AM
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Draining the boiler (furnace) for service

Hi all,

I'm trying to drain my baseboard system of all water.

I turned of the power

I closed the incoming water valve

I opened the red faucet in the first picture - no water coming out

I opened the faucet top right in the second picture - very slowly getting water to come out

If i open both at the same time, same result - only the top faucet leaks out water very slowly

Am i missing a bleeder valve? Is it something on top of the expansion tank? (i didn't want to touch it yet)

I could continue to empty through the top faucet, but i would have to get a short hose connection, so that i don't have to keep standing holding a bucket, because that would take too long. I also feel that that would only empty "half" of the system.

I know for a fact that you can empty the whole system without leaving the basement, because some technicians did this when replacing the expansion tank before.

Thanks for reading and thanks for any responses! Let me know if I missed any information...

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Last edited by PJmax; 06-25-19 at 11:55 AM. Reason: imported pictures
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  #2  
Old 06-25-19, 10:53 AM
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D,
You should be able to drain some from the faucet on the boiler if you want to drain the whole system. You may be pulling a vacuum and need to let air in to release it. If you put a bucket under your relief valve and open it. You will get some water out from there and then leave that valve open and open the drain on the boiler for a complete draining.

The main thing you must do is break that vacuum like taking your finger off the straw filled with water to let it drain. That vent cap on top of the expansion tank should be loose.

PJ may change your post to BOILERS. You have a boiler which heats water and not a furnace which heats air.

Hope this helps a little.
 
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  #3  
Old 06-25-19, 12:05 PM
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Why are you wanting the drain the system? Unless it's necessary for some special repairs or maintenance, routinely draining the system is not recommended - when you refill the system, the replacement water will be loaded with dissolved and entrained air, which will cause accelerated corrosion. You will also likely need to bleed the newly refilled system to prevent blockage of various loops and heat emitters - often a laborious process.
 
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  #4  
Old 06-25-19, 06:51 PM
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Thanks both for the responses! The reason I need to empty the water is because i will be moving some of the baseboards, so i need them empty before moving them.

I will try loosening the vent on top of the expansion tank (if i understood that right).

Thanks for clarification on furnace/boiler distinction too! Never knew the difference!
 
  #5  
Old 06-26-19, 11:05 AM
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D,
Only the vent cap, not the vent. If you remove the vent, system water will come out with no way to stop it until the water gets below that level.

On a side note if you are draining the water only to move the baseboards you do not have to drain the whole system. Drain only as much as you need to get below the point of the units to be removed.

Something that may help with breaking the vacuum. Since your removing the baseboard if you open up your drain valve either on the return or the boiler and make a small cut in the baseboard pipe that you are removing, that will allow air to break the vacuum and the water will drain to a level you can work with.

As gil mentioned fresh water is the boilers worst enemy.
 
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  #6  
Old 06-27-19, 05:30 AM
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Thanks again!

I put it off for a few days, but I will give it another go...
 
  #7  
Old 06-29-19, 07:05 AM
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Ok, some success,

I went to the top floor and drilled a small hole in a piece of pex pipe that i was able to bend up so that it was the highest point of the system. It sucked in air right away.

Went to the basement and opened the lower faucet on the bottom of the boiler. Still no water coming from there!

I opened the top faucet (top right in the second picture of the first post) and it let out water freely. I got out about four gallons.

Very surprised that the bottom faucet is still not letting out any water, but maybe this is enough to complete the work that i am planning...
 
  #8  
Old 06-29-19, 07:34 AM
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It's possible that the drain valve is blocked with crud. I happens if the valve is not exercised routinely. You can try loosening the stem packing nut on the valve, and maybe that will free up the valve. But otherwise, while you have the system drained, replace the boiler drain valve. With the valve removed, rheem out the drain connection with a stiff wire, and flush. You do need a working drain valve.
 
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  #9  
Old 06-29-19, 10:54 AM
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D,
You should be able to get water out of your boiler valve unless as gil said , it is blocked. What you can try is to shut your yellow handle ball valve off on the return line under your drain valve. This will let your feed water go into your boiler only and not backfeed up the return line.

Open your boiler drain then open your cold water valve that you shut off to drain the system. That will let water in and with the boiler drain open it should come right out. If it doesn't then as gil said your boiler drain is clogged and must be cleaned or replaced.
 
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  #10  
Old 06-30-19, 05:17 PM
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Thanks guys!

There were technicians here in April that drained the system as they replaced the expansion tank, so the drain was fairly recently used...

After draining that bit of water I went ahead with my repairs, I have removed two of the baseboard radiators from the top floor, so the system is open (though the first floor is on a different circuit). I got out just a bit more water from the pipes as i removed them.

I live in a flipped house where they did some poor installations. All the baseboards are mounted on the wooden floor trim (instead of removing the trim first) which looks terrible. I am taking out the baseboards, repainting them and removing the trim, so that i can install them flush to the wall like they are supposed to be. I'm doing the top floor now. Later i will do the first floor, so i will see if i try to drain some more then or actually just cut a pipe and drain that way.

Thanks again for the tips. I will probably come back later with more "noob" questions. Especially when it comes time to fill the whole system again!
 
  #11  
Old 07-01-19, 09:14 AM
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D,
This is just a thought since you posted why you removed the baseboard. When you reinstall the baseboard heat without the baseboards depending how they were piped you will most likely find the holes are not lined up and may be to far forward and may not fit into the covers.

Just a thought.
 
  #12  
Old 07-02-19, 05:06 AM
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Yes, I will drill new holes through the walls so that the radiators are routed closer to the wall they are mounted on. Not a problem since I am removing and reinstalling the whole thing. Thanks.
 
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