boiler feed valve normally open or closed

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Old 02-07-06, 07:32 PM
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boiler feed valve normally open or closed

I've read a lot of the threads dealing with purging a closed heating system. I have a closed system with no in line bleeder valves and 4 zones.

Should the feed valve from the main water line normally be open or closed?

Can someone fill in the gaps with what I need to do to purge the system(or correct what is wrong).
1. Hook up hose to spighet between drain valve and boiler shut off valve to drain into bucket.
2. Shut off return valve to boiler.
3. Ensure feed valve is open.
4. Open one zone valve and corresponding drain valve.
5. Wait for air to stop coming out.
6. Close drain valve and then close zone valve. Zone done
7. Move hose to other drain and repeat from step 4 until all zones complete.
8. Anything else?????

Ohh yeah, it's really cold here right now and I don't want to risk loosing heat right now, should I still proceed?

Questions:
How do I open the electric zone valves?
Should I turn off the power to the system?
Should I check the pressure in the air tank? What should it be for a two story house with a basement?
I have an air eliminator or vent on the top of an american air purger, shouldn't this remove the air from the system? Does the air eliminator require any maintenance? What does the little valve thing on the top do?

THANKS!!!!!
Sieler
 
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Old 02-08-06, 04:51 AM
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First of all, if you have heat right now, and all is fine, why do you want to belled the system? All you are doing is introducing more air into the system and adding fresh water which is really not good for a boiler. The best thing you can do to a boiler to promote longevity is leave the old water with all the dissolved minerals already in your system.
 
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Old 02-08-06, 05:33 AM
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If you have a low flow sensor and/or low water cut-off device - fee valve off

Logic
- if your system springs a major leak you won't have a flood with the autofill adding to it
- if you do lose water, the boiler will shut down before the boiler gets harmed



Without a low flow sensor and/or low water cut-off device - feed valve on

Logic
- if the system loses water or pressure, the heating system could be damaged although there is more risk of having a flood if a major leak occurs


Now with that, there are many that would argue that they would run with the feed off even without a flow sensor or LWCO.



As for gaps in your fill purge checklist, I would only be guessing and assuming things about your system. You may wish to ask the person who does your annual servicing because they would be familiar with how it is piped.
 
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Old 02-08-06, 06:35 AM
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I guess I didn't mention why I need to purge...

I've been hearing a lot of bubbles and gurgling going on telling me there is air in the system. I'm new to this kind of heat so I'm not sure how much of this I should hear.

Also, two of the bedrooms upstairs stay considerably colder than the other bedroom and bathrooms. The two that stay colder are on the back of the house.

I also though that with all that air, there would be a lot of inefficiency.

Do you know if the air eliminator could remove the air in the system if it is working correctly?
 
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Old 02-08-06, 06:38 AM
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One more thing. If my feed valve is closed, could the air eliminator work? Could I just turn on the feed valve and run through the zones and let the air eliminator do its job?
 
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Old 02-08-06, 01:00 PM
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What kind of expansion tank do you have? What kind of air elimination do you have? Where are these in location to the circulator?
 
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Old 02-08-06, 08:17 PM
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Allow me to draw a schematic in words:

Feed line from water main through valve into what I think is a backflow preventer

Bottom of BFP attaches to top of expansion tank-blue, about 4.4 gallon tank with schrader valve on bottom of tank

Top of BFP goes to bottom of American Air Purger

Top of AAP goes to air eliminator? No writing.

Air eliminator and AAP and Air Tank look just like the ones here:
http://cgi.ebay.com/ws/eBayISAPI.dll...category=20598

Side of AAP attached to boiler

Other side of AAP splits into 5 parallel pipes with manual valves

4 of the pipes have electric valves for the 4 zones (5th has no electric valve??)

After traveling through the house, the 5 pipes return all through a drain valve then a shut off valve then merge together and into the pump

On other side of the pump, there is a drain valve and an attachment to the boiler

I have a single switch for the 120vac that powers the boiler and 24v transformers supplying the thermistats

My feed meter reads 0 so I'm guessing the feed valve is off (I didn't turn it)
My red needle reads 10lbs, is this my system pressure that is regulated by the air tank?
My temp is 180

Why isn't my air eliminator eliminating air?
What is the 5th mystery circuit that doesn't have a thermistat?

THANKS
 
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Old 02-09-06, 06:04 AM
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Ideally, your system would be boiler, air elimination and expansion tank, circ, tees, heating branches, zone valves, tees, boiler... Systems work best when they are pumping away from the air elimination and expansion point.

The air elimination works as the water passes through it. It scoops the air and then that air goes out the autovent. There are better air elimination devices like spirovents, but the one you have will last forever. The little autovent won't but they are cheap and easy to replace and you should try and see that it releases any air but won't release water.

The feed gauge reads 0? On the one side of your autofeed is your domestic water supply for the rest of the house. It would be 40 or more pounds. What you are probably seeing is the boiler system pressure. 0 psi is bad. The red line you see is the minimum it should be. You should have at least 10# in there and when it is hot it shouldn't go much above 20# or you have expansion tank issues. Get the system up to 15 pounds and see if it holds pressure. If it doesn't, you are someone is going to have to find out why it won't hold its pressure. That's step one and until that is done, I wouldn't even bother trying to worry about purging the air because it is just going to keep reoccuring with the leak.
 
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Old 02-09-06, 05:30 PM
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Thanks Who,

You're correct. The pressure in the system is 0 based on a reading from the schrader valve. I tried pumping it up, but I don't have a very good pump for this but it wouldn't hold any air. I could hear it escaping from the valve.

Is this something I could replace myself? Any idea how much it would cost to have replaced? How would I do it. I'm assuming that removing it would open the closed system requireing a replacement of some of the water. Any more help?

Thanks
 
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Old 02-09-06, 05:40 PM
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Tank replacement

Since WHO is offline, I'll try to help. The tanks are not expensive (well under $100) & easy to replace. Just be sure to get the same brand as the one you currently have. Sometimes you can interchange brands, sometimes not. To replace, shut off the water & any valves between the boiler & tank (or drop the system pressure to zero), apply teflon tape or a teflon based pipe dope to the threads of the new tank, unscrew the old tank, & screw on the new one.
 
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