Heating problem with some radiators cold while oithers are warm


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Old 01-01-07, 01:25 PM
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Heating problem with some radiators cold while oithers are warm

I have a very old Arcoliner oil burned boiler, the model/series is "no. W O 551 Series 3b J3". Recently, some of the radiators are not heating up. The riser pipers in the basement directly under these cold radiators are all hot. I am a newbie in this area and I don't even know if the system is hot water or steam based. Can anybody shed some light as to how to go about diagnosing and fixing problem?

Thanks a lot in advance.
 
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Old 01-01-07, 02:11 PM
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Cold Radiators

If the system is hot water, there should be a circulating pump in line with the piping near the boiler & a tank of some sort attached to the piping. Another tip off would be the boiler gauge. If it reads somewhere around 10# or higher, it is a hot water system.
Presuming this to be hot water & cast iron radiators, there should be some kind of small bleeders on the ends of the radiators such as those pictured here: http://www.homeandbeyond.com/prod-0077908.html
Most require a key such as the one pictured with the vent but some have a screwdriver slot. Open the vent & hold a cup or other container under the vent to catch the water. Allow the vent to expell air until you get a steady stream of water.
 
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Old 01-02-07, 02:25 PM
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Cold radiators

Thanks Grady. I think it is a hot water system because there is a circulating pump near the boiler. I opened the bleed valve with a wrench and nothing came out (no air no water). It can't be the water level problem since other radiators on the same level are working fine.
 
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Old 01-02-07, 06:09 PM
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Cold radiators

Several possibilities here. The most common is a pluged bleed valve. If it is of the type shown in the picture, use a pin to try to clean the small spout. If you turned the whole vent, you should not. If the vent is the type with the small square in the center & no screwdriver slot, you will need a radiator key. Most plumbing supply houses have them. Just turn the inside part. Another possibility is a valve closed somewhere.
 
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Old 01-05-07, 02:59 AM
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Yiming - I had a similar problem last year and with Grady's help, we were able to determine that my boiler was low on water. As I added more water (had a manual fill) the hot water would gradually rise to the radiators that had been cold. Many trips back & forth from basement & 2nd floor to bleed and add water, but everything worked out fine. My initial conditions were some radiators on 2nd floor were hot and others not. I'd say you either have a manual fill valve or your automatic fill valve is not working correctly. Also check your pressure gauge on the boiler: if it's reading low (say < 12) after it's been on for awhile, then you're probably low on water. I believe Grady said about 18 should be normal, but you might want to check the archives for this information just to make sure.
 
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Old 02-19-07, 02:31 PM
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still need help

Grady and Bren,

Thanks for your repsones. I had been away for a while and kinda lost track of it afterwards. I am still having the problem and getting worse with more turn cold. The presure needle in the tridicator is at 0 which, according to you guys, leads me to believe it's the water level issue. Given that, I really appreciate if you can instruct me on how to locate the fill valve (not sure if it's manual or auto) and what to look for next? Thanks.
 
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Old 02-19-07, 02:53 PM
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They are generally in a 1/2 inch galvanized steel or 1/2 inch copper line that connects up with the water supply of the house (that your faucets and other house plumbing is on.) Trace this to know that indeed is the line. Then this line will have, lots of times up by the ceiling, an auto-fill valve and even a backflo preventer. In other words, there are devices on this 1/2 inch water line. The water line then enters near the lower part of the boiler.

The auto-fill valve will have a nut and screw-bolt ontop. You loosen the nut some. Then you tighten...yes TIGHTEN... the screw bolt down some (clockwise), and this will INCREASE the water pressure in the boiler by adding water. If you have a water meter near by, you can watch the amount that is going in. You will also hear it going through the pipe. MODERN auto-fill valves can have a manual lever on them where you can rapidly fill the water by bypassing the pressure regulator part of the auto-fill valve.

If you leave your system on auto-fill, you want to make sure that the pressure in the boiler stabilizes at 12-15 pounds, cold, on your pressure gauge on the boiler. If you hear water still trying to come through the 1/2 inch pipe and you are already at that mark, then you must back off on that screw-bolt till the water flow stops. But you really want to start backing of at about 10-1 psi so that you hear the water gradually starting to taper off so that you know that when it is on auto-fil, it has come to a stop and it will maintain that 12-15 psi without gaining psi or losing it.
 
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Old 02-19-07, 04:43 PM
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Yiming

Some photos of the boiler & nearby piping would make it a lot easier to explain to you on what to do. Since we cannot post pictures on this site, you can post them on photobucket.com or similar photo hosting site & provide a link here.
 
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Old 02-19-07, 08:46 PM
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pictures

Here are a few pictures I just took.

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0309.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0306.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0299.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0301.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0303.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0304.jpg

http://i152.photobucket.com/albums/s194/yiming__bucket/IMGP0300.jpg
 
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Old 02-19-07, 08:54 PM
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You may want to nurse it 'til spring and then replace it all. It's time is done... lots of air issues with your system. The conventional tank's a work of it and also one of the culprits.
 
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Old 02-20-07, 03:54 AM
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In the first and last pictures the assembly on the right is the "automatic" make-up water valve, more properly called the make-up water pressure reducing valve (PRV). The lever handle on top, when raised, manually opens the automatic valve and will allow water into the heating system.

If raising this lever does not let water flow (you should be able to hear it) then follow the piping coming into the right-hand side of the PRV until it connects to the domestic water piping of the house. There most likely will be a valve in this piping somewhere and you need to be sure the valve is open. If it is, and you still cannot get water through the PRV then there is a blockage, most likely the PRV itself is full of rust.

You may want to (gently) tap on the pressure/temperature gauge when trying to fill to see if the gauge is stuck. Proper pressure when the system is cold will be about 10 to 15 psi. The gauge is probably not accurate.

If the pressure rises quickly, especially when the temperature is risiing, then the expansion tank (the tank in the overhead, picture 5) is "waterlogged" which means there is too much water in the tank leaving no room for the water in the system to expand when heated. It needs to be drained by attaching a garden hose to the drain valve on the far end and then draining the water. There won't be much water draining because it will soon create a partial vacuum in the tank and it will be necessary to somehow add air to the tank to break this vacuum. You may be able to simply blow (hard) into the end of the hose several times to empty the tank. If you have access to an air compressor you may cobble up some fittings that will allow you to pressurize the tank through the drain valve prior to draining. Do not add more than 25 psi of air pressure at a time if you do this.

There is nothing wrong with non-diaphram expansion tanks such as yours, there are literally tens of thousands of them in existance and they continue to be manufactured and installed. They do require a bit more in maintenance than will a diaphram tank.
 
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Old 02-20-07, 03:31 PM
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I gotta say, that is a cool old system!
my fave is pic 304 I think.

It appears to have been pretty well maintained over the years, a few minor problems maybe, but overall, good condition.
 
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Old 02-24-07, 01:21 PM
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I tried manually feeding the system with water per furd by rasing the lever on the RPV. This seems to be working as the pressure stablized at around 15 and all the radiators gradually turned warm after serveral days. I am glad it turned out to be an easy fix. My remaining questions: should I replace my auto fill RPV or is it OK to monitor and do manul feed when necessary? Thanks for all your help.
 
 

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