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Old 12-07-2010, 08:45 PM   #1
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Boiler not filling


Hello,

I'm a new homeowner this year. I have radiator heat in my house and this winter I read up on how to bleed my radiators. As I was doing this, I noticed the pressure in the boiler was about 4psi, and it dropped to pretty much 0psi after i let some air out of the radiators. So after contacting an HVAC specialist, they said I need to add water by opening my fill valve. I did that and didn't hear any water flowing. They sent someone out and they said my galvanized pipes had clogged the fill valve and or backflow preventer. It would cost a $1,000 to have it replaced (and remove galvanized pipes).

I read up on my fill valve (it's a B&G FB38) and saw that the filter may be clogged. I turned off the cold water supply and removed the filter, it was clean. Just to test, i slowly turned the cold water on and tested the fill valve and nothing came out at all. So it seems like water is not getting through the backflow preventer. Is this a component that can have issues, and can i easily replace it myself? I'd hate to spend a grand if it'll cost me a few hours and 1 new valve.

I am very new to plumbing, but this is the kind of stuff I want to learn. If this is a DIY job, can anyone provide the steps I'd need to take to troubleshoot/replace these parts? I'm a beginner so please be as specific as possible.

I'm attaching a picture for reference.

Thanks in advance for all your help,
Andrew
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Old 12-07-2010, 08:56 PM   #2
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Boiler not filling


I have the same type of components on my boiler, and recently replaced my fill valve. I purchased a new Watts fill valve for about $40 at a big box store, and I installed a backflow preventer (there previously was not one in my system). The backflow preventer cost about $20.

These parts are easy to test. The backflow preventer has an arrow on it that shows you the intended direction of flow. To test it, you shut off the flow to the backflow preventer via a valve, remove the fill valve which is downstream of the backflow preventer, then open the valve to the backflow preventer. Water should flow through the backflow preventer in the direction of the arrow. If it does not, the backflow preventer is bad.

If the backflow preventer is OK, the likely culprit is the fill valve. My old one was so clogged with rust that water would not flow through it. You can easily check it by removing it and taking a look at it, it was clear that mine was shot by visual inspection.

Before you remove parts, be sure you make a sketch of the parts so you can replace them correctly. Also, your system probably will include some combination of sweat fittings, threaded fittings, and possibly a union. Be sure you know how to install each type of fitting before you take the system apart, and be sure you have the right size parts such as unions, copper connectors, pipe dope, teflon tape etc. Also the right tools like a torch, solder, pipe wrenches etc. And of course be sure to shut off the water first.

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Old 12-07-2010, 09:04 PM   #3
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Boiler not filling


Thanks Daniel,

My major concern is putting it back together with the new parts. Pipe dope, teflon tape, etc.. I'm not sure when I would use each. I've never soldered anything either. It looks like most of the connections are not soldered, except maybe the conection between the fill valve and backflow preventer. The vent from the preventer also has a bend in it, so it was soldered with an elbow joint. I guess it may be a good time to learn all that.

Do you have any good references on sweat fittings, and unions? i think i can handle threaded fittings.
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Old 12-08-2010, 05:16 AM   #4
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Boiler not filling


In the mean time until you get the valve replaced.

take a utility hose, and use it to put water back in your boiler.
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Old 12-08-2010, 08:01 AM   #5
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Boiler not filling


I wish I knew this last night, freezing in the house! Anyway this morning I took a look and don't see anywhere that I could hook up a hose. Whould this be directly to the boiler, or to the pipes leading in?

Thanks for eveyone's help.

Andrew
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Old 12-08-2010, 08:58 AM   #6
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Boiler not filling


Quote:
Anyway this morning I took a look and don't see anywhere that I could hook up a hose. Whould this be directly to the boiler, or to the pipes leading in?
Ayuh,... There should be a hose bib at the bottom of the boiler, for draining it...
You can hose fill it from there...
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Old 12-08-2010, 05:17 PM   #7
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Originally Posted by Bondo View Post
Ayuh,... There should be a hose bib at the bottom of the boiler, for draining it...
You can hose fill it from there...
Yep. Done it many times instead of changing out a combo feed relief valve at 1 or 2 in the morning.
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Old 12-08-2010, 09:38 PM   #8
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Boiler not filling


well, i was able to fill the boiler up. It was about 14psi. I turned the power back on and then turned on the thermostat to start heating. I watched it for about 10 mins... the temp rose but the pressure stayed pretty constant. So i went upstairs and about an hour later, heard a big boom. Looks like the relief valve opened, there's water all over the floor. Sooo... of course now i'm nervous and I have the whole thing turned off again. The pressure is reading 1psi, but I have no idea what it read when the valve blew. Are there any next steps to take? Do i need to reset the relief valve or anything? Is it time to have a professional do it? Thanks
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Old 12-09-2010, 03:35 AM   #9
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Boiler not filling


Do you have a large steel tank in your basement, that is connected to the boiler. If so, it is probably full of water and needs completely drained.

Most likely. Your rads were acting as an expansion tank. And when you drained them, the water had no place to go when it was heated.

The relief valve opened when the system pressure reached 30PSIG.

Post pics of your tank set up. Then we can see which valves you need to lose and open to drain it.
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Old 12-09-2010, 07:18 AM   #10
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Boiler not filling


Is this a water boiler or steam boiler??
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Old 12-09-2010, 06:25 PM   #11
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Boiler not filling


OK. It's a water boiler. I'm trying to get some pics, but in the mean time. After the relief blowout last night, i turned the system off. I turned it on today and the initial presure was about 8 psi. I've been watching it and the pressure has been slowing rising. It's at about 18psi now. I'm probably going to cut it off bc i don't want it to hit 30 and blow again. Could this be an issue with my expansion tank? My understanding is the pressure shouldn't chnage much because the expansion tank air chamber will absorb the expansion of the water. So could the air part of the tank not have enough air in it? There is a nipple on top that looks like you could add air. Also, the expansion tank is cooler all over. Shouldn't hot water be in the bottom half of it? Maybe the pipe is clogged going into the expansion tank? Turning it off for now, may run it for another hour before bed for a little more heat. I'll try to get some pics up soon. Thanks everyone! I'm learning a ton through all this.

Andrew
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Old 12-09-2010, 06:55 PM   #12
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Boiler not filling


There are 2 types of expansion tank. Bladder or sealed type in first pic and torpedo/old school steel pic two. The second needs draining, the first just needs proper air charge. Which do you have?
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Old 12-09-2010, 07:10 PM   #13
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It's a bladder. The pipe leading to it is very hot. But the tank it's self is cool. That just doesn't seem right.
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Old 12-09-2010, 07:14 PM   #14
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Boiler not filling


Post lots of pics of the boiler and piping to that tank AND a video of the boiler/piping etc on You Tube and link it here. Try setup some trouble lights for better lighting. Beenthere is our resident hw heating Pro and the rest of us know some too but we cannot see what you have w/o better info/pics.
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Old 12-09-2010, 07:19 PM   #15
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Boiler not filling


Ok, I probably can't get a you tube up til Friday night. But here's a picture of the whole setup. This weekend I should be able to get a lot of pics and a vid. Thanks
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