Oil-fired Forced Hot Water System Leaks Water

Hi,
We have an oil furnace that uses forced hot water to heat the home. The system also provides hot water to the household for showers, etc. It is a Connecticut home that was built in the early 1960's. I can barely afford this home so I've been trying to get every last breath of life out of this furnace.
My problem right now is that the system leaves a large puddle of water. After I mop of the puddle, another will be in its place 24 or 48 hours later.
Last year a repairman looked at this and told us that the 'water jacket' is not cracked. The water is resulting from "overflow". He tweaked something and the problem went away for a long time.
Unfortunately he told my wife how to prevent this from happening in the future by turning a relief valve, etc. However, my wife was not able to effectively repeat his instructions to me.
Can someone give me some idea what I might do to stop the "puddles"?
\\cbf
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I would suggest first contacting the service guy who knows the system. It sounds like the leak is coming from the pressure relief valve and not the boiler itself. This is a brass valve with a lever on it and usually a pipe aiming down to the floor. This valve will blow off on high temperature or pressure. The valve could be bad, the water pressure feeding the boiler could be to high, or the boiler could be overheating, causing it to blow.

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Very likely the case. Replacement is simple if you have a little experience with using wrenches. One of the most common is a Watts brand that sells for about $65.
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Had a similar problem. Expansion tank was over filled and full of "guck".
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wrote:

My boiler was doing the same thing last winter. You could watch the needle on the pressure gage slowly creep into the red zone as it came up to temperature, then see water start to trickle out the overflow pipe. It turned out that the pressure relief tank had become, in the words of the service tech, "water logged". He simply drained some of the excess water inside this tank (thereby restoring the air space required for it to do its job) and the problem went away.
Cheers, Paul
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On Sun, 03 Feb 2008 04:30:39 -0800, cbfernald wrote:

I am going off on a tangent which may not have anything to do with your problem, this is from my memory of living with a hot water heating system a a bit more than a decade ago.
With my system, up in the rafters of the basement was a cylinder; it looked about like a 10 gallon black metal cylinder. This, I was Told, was an expansion tank for the hot water. My system was not rated for the circulated hot water to build up pressure (county building code thing.) Inside the tank was a rubber membrane, air on one side, and furnace water on the other side of the membrane. On the air side of the tank, there was a low point with an air bleed valve, to regulate the air pressure (or vacuum in summer) caused by expanding / contracting hot water.
The pressure relief valve on the system, I was told, had a high temp / pressure release point. I was told, IIRC, that if any water leaked from the pressure relief valve to 1st open the air valve on the expansion tank and release "some of the Air Pressure". (I put that in quotes, as I didn't get specific air pressure instructions.) I was, however, given explicit and specific instructions that when I opened the air valve, to keep a hand under the valve to see if any water escaped with the air; a sign the tank needs replacement.
With a "KA-CHING" in his eyes, the Hot Water Furnace guy told me the tank replacement was not a homeowner type of thing. Later I remember having a good hard look at the furnace pipe connecting to the tank, and the bracing of the tank in the rafters, and mostly I agreed a job like that should be left to someone else with more pipe soldering skills than I will ever have. I just knew that I would most likely set one of the rafters on fire.
Again, this is a bit off topic and may not apply to your local building code.
Phil
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On Sun, 03 Feb 2008 15:14:35 -0000, Phil again

Hi Phil,
I swear my ISP's news server is hooked-up to a crank telephone on a party line, so I didn't see your post until after I had uploaded mine. I think all of us are fingering this as the most likely cause and, hopefully, the OP can drain some water and correct the problem without encountering any out-of-pocket expense.
When I had my new boiler installed five years ago, they didn't bother to replace the pressure relief tank and, in hindsight, I wonder if that should have been done.
Mine is very similar to what you described. You can find a picture of it here: http://www.datafilehost.com/download.php?file 173172
Cheers, Paul
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On Sun, 3 Feb 2008 04:30:39 -0800 (PST), cbfernald

Sounds like a "water-logged" expansion tank to me. Best repair is to shut off the valve that feeds to that tank. (It may or may not have one depending on who installed it.) Next, open the drain to that tank and drain the entire tank. When finished draining, slowly, SLOWLY open the shut-off to that tank. The tank will refill, slowly, and only refill to about half the full capacity due to the air in the tank. This is what you want. Keep in mind that the water refilling that tank is coming from your system. If the incoming city water pressure reducing valve doesnt keep up with the rate you are refilling the tank, then you will get air in your system. Not a big deal really, just that you will usually then have to purge the air from your upper floor radiators. Bubba
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