Hot water heat - Cold Radiators Upstairs


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Old 11-18-05, 11:06 AM
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Hot water heat - Cold Radiators Upstairs

We bought our house in July, and it's my first experience with hot water heat. I have a forced hot water, two-pipe system in a two story house with radiators. Everything's on one zone with one thermostat in the living room on the main floor. My furnace and pump (in the basement) seem to work fine with water consistently heating up to 180 degrees and pressure in the system consistently staying at about 18 psi. I don't think my expansion tank is waterlogged.

All of the radiators on our main floor heat up nicely, and I get a steady stream of water out of each one of them when I open the bleed valve (with the exception of one that will sputter a little bit of air). Upstairs is a different story. I have five radiators upstairs, and they all stay stone cold.

We did have a repair guy come by last week. He cleaned the system for $89, and he told my wife (I was at work) that there's a lot of air in the system that needs to be bled out and that there could be an air pocket somewhere that's preventing water from getting upstairs. He recommended bleeding the radiators one at a time, alternating between upstairs and downstairs.

I've been following the repair guy's advice, alternating upstairs and downstairs radiators. At this point there's one radiator on the main floor that will periodically spit out some air, but I get mostly water from it. Still nothing upstairs. When I first fired up the system this fall I was getting two radiators out of five upstairs to heat up. We had a leak in the water valve on our master bedroom radiator (this is one of the two that was getting hot). I tightened one of the large screws on the outside of the leaky pipe, which stopped the leak, but now the radiator won't heat up (though it does bleed small amounts of air from time to time). The other upstairs radiator that was getting hot when I first fired up the system seemed to suck in some air when I opened the valve last night, and now it doesn't get hot at all (I've never gotten water out of that radiator). All of the upstairs radiators will occasionally bleed some air, and sometimes they'll suck in air when I open the bleed valves. This doesn't seem good.

Here are some questions:

--Should I just open up the valves on all of the upstairs radiators, turn the thermostat way up, and just let the system run until the upstairs rads start to get hot and bleed water?

--Is there something that a fairly non-mechanically-inclined person can do to bleed air at the source (where the pipes come in and out of the furnace)?

--I've read in a few places that it can help to increase the pressure in the system in an attempt to force water into stubborn places. Is this adviseable, and how would I do it?

I know there are tons of posts on bleeding radiators, and I've tried to follow all of the advice I've read, but I'm just plain stuck. Many, many thanks in advance for any and all advice!
 
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Old 11-18-05, 06:29 PM
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Cold rads

With that one radiator sucking in air, I question the accuracy of the pressure gauge. If the tank were waterlogged, the pressure would go up wen the system heats & cause water to come out the relief valve.
Presuming you only have one thermostat: Turn it off or all the way down & start bleeding air from the radiator which is the highest & farthest from the boiler & work your way back toward the boiler.
 
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Old 11-18-05, 06:38 PM
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I had a similar problem last fall and the people at this forum helped me alot. Reason my upstairs radiators wouldn't heat up is because water level in my boiler was low. This was indicated by pressure needle registering way below altitude needle. My system had a manual fill compensator and all I did was run a little more water in at a time, let the system heat up and then see if pressure needle was getting close to altitude needle. Solved my problem and I hope this helps you.
 
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Old 11-18-05, 06:46 PM
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Altitude Needle

If you have the kind of gauge I think you do, that altitude needle is fixed & does not move with the pressure. If the other needle is below 15-18#, add water until it gets that high. Just to check it's functionality, run the pressure up to about 20-22#. If the needle does not move as you add water, it does not work & the gauge needs to be replaced.
 
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Old 11-18-05, 08:05 PM
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water in system

Thanks for the advice Grady and bren! I have now noticed that the valve just above the expansion tank was closed, so no new water was getting into the system. I've opened that valve, and I'm letting the system run right now to see what happens.

Regarding the altitude gauge, I don't see one anywhere. I have one gauge on the boiler with two needles, one for temperature and one for psi. The psi gauge is sitting squarely at 18.

It is beginning to sound like I may have a bad pressure gauge. I'll keep you all posted!

By the way, Grady suggests turning the thermostat down and then bleeding the system (presumably with the circulator pump off). I thought that the idea with bleeding valves was that you wanted to have the circulator pump running in order to move water (and air) through the system. Is that wrong?
 
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Old 11-19-05, 04:21 AM
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If your pressure didn't increase when you added more water, then the gage is probably broken, but I'd wait 'til Grady comes back on to verify this. My boiler is rather old, so your gage set-up is probably different. I have an altitude scale that parallels the pressure scale and the needle on the former is set to about 30 feet -- pressure reads about 18 when that needles match. You should see some immediate results after you bleed the radiators upstairs (whether circulators are running or not). Just be careful not to overfill boiler which may be a distinct possibility if in fact your gage is broken
 
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Old 11-19-05, 07:23 AM
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Thanks Bren. We're leaving town today to go visit family for Thanksgiving. I'll be back next Saturday, when I'll resume my efforts. I didn't make any progress last night in getting the upstairs rads to warm up, but I think I am making progress in understanding how my heating system works, and that's a good start.

From what I can tell, I have an automatic fill compensator that was turned off (this fits the MO of the former owner, who had also turned off the main gas shut-off valve). I'm quite sure that my system doesn't have enough water in it between one radiator that leaked quite a bit before I got it fixed and others on the main floor that I've bled a lot of water out of while also getting all of the air out. I didn't notice that the boiler pressure increased last night when I turned the water on, but I'm not going to call this a broken pressure gauge just yet. Even though I've turned the water on, I'm not sure that any new water is getting into the system. I think one of the valves in the automatic fill compensator may be bad.

However, I suppose the problem could also be a bad pressure gauge which isn't triggering the fill compensator to kick in. Though it seems to me that the pressure (or lack thereof) in the expansion tank is what would trigger the water to come on, regardless of what the pressure gauge on the boiler is showing. Maybe it just takes a long time to get enough new water into the system to get to my upstairs radiators. Maybe I'll get back next week to find that everything's working great! Yeah, right...

Bye for now...
 
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Old 11-19-05, 07:41 AM
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ReidJH, Re: Circulator off

There is no hard & fast rule for bleeding air. I have been most sucessful with the circulator off to get the bulk of the air out because it allows the air to form pockets & come out in a "slug" rather than little spurts. After bleeding, I then turn the circ on to hopefully move any pockets of air. If there are zone valves in the system they have to be locked open for each loop you are bleeding. Getting all of the air out is often a long process. Once I get the bulk of it out & there are functioning automatic air vents, I let them finish the job rather than having to charge the customer for what could be hours of work.
 
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Old 12-09-05, 08:01 AM
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Still trying to get system working

Grady,
I've been working away at my system still trying to bleed air and still having the problem of radiators upstairs sucking in air about as frequently as they release it, all while staying stone cold. I've spent a lot of time messing around with the pressure reducing valve lately, and I think that may be the problem. I read in another posting of yours that it's this valve that should provide enough pressure to push the water upstairs. Well, this doesn't seem to be happening in my system. There's a clean out on the bottom of the valve. I took the clean-out nut off the other night, and I found that the strainer was completely corroded to the point where it was not letting water through at all. There are also signs of corrosion on the outside of the valve (it's a Bell & Gossett valve). Could my solution of getting heat to my upstairs radiators be as simple as replacing the PRV?

Many thanks!
 
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Old 12-09-05, 05:25 PM
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Prv

Replacing the PRV certainly could be the solution to your upstairs problem. If it does not feed water or only feeds very slowly, it would definately make the bleeding process tough. I use the B & G model FB-38. They come preset for 12 psig so you may have to turn the screw in a little.
 
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Old 12-10-05, 05:39 PM
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Thanks for the feedback Grady. I'm going to get a new PRV installed as well as the B & G "PowerPurge" isolation valve. I'll post back with results.
 
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Old 12-30-05, 08:57 AM
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It's fixed!!

I thought I'd make a final posting here to share the good news that we finally have heat upstairs! After spending a lot of time researching the problem through this forum, I knew enough about my problem (the PRV valve) to explain it thoroughly to our home warranty provider, which means that they finally agreed to cover it, and they brought in a very competent local heating & cooling repair company to get the problem fixed.

When the repair guy came (Mark from Locke's Heating & Cooling here in Cincinnati...I highly recommend him to others) he agreed that I had a bad PRV valve, then he went on to diagnose a bad expansion tank, and a bad pressure guage. I didn't know that checking the expansion tank was a simple as using a tire guage, and I already suspected from one of Grady's posts that the pressure guage was off. Last, but not least, he found a gas leak at the pilot light switch on the boiler. It's amazing this system was working at all!

He was able to get the gas leak fixed before we left town for Christmas, and he came back yesterday and fixed everything else. It's now working like a charm.

Thanks to everyone here for helping to educate me on hot water heating systems!
 
 

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