Boiler High-water Cutoff Problem

[krishna prasad]

I apologize in advance for the length of this question. I dont know which facts are important, so Im including everything that might be pertinent.My house was built in 1927, and the Utica Radiator Company boiler is about 20 years old. It is a gas-fired, single-pipe steam system, and it has been working very well for the three years that I have owned the house. The previous owners told me that it had been very reliable.The previous owners removed two radiators from the ground floor, and capped the pipes. The living room and entrance hall (about 1/3 of the ground floor, in all) were converted from radiators to steam baseboard. A huge radiator in the garage was also disconnected, two owners (50 years?) ago.Several months ago, my plumber removed all of the radiators from the house, and we had them dipped to remove interior rust and exterior paint. (The steam baseboards were not removed.) The radiators were then powder-coated, and all of the vents were replaced, before the radiators were re-installed. Some of the valves were also replaced. We have been checking for leaks, and havent found any.When he re-installed the radiators, my plumber recommended that the boiler be cleaned out with a powdered chemical of some sort. He did so, and at the same time he installed a cleanout on one of the pipes, right at the boiler, to make future cleanings easier. No other mechanical work was performed, as far as I know.It may also be important that, while the renovation is taking place, we have temporarily removed and capped the radiators in the kitchen and breakfast room, plus the large bathroom on the second floor. One radiator on the second floor is turned off at the valve. That leaves us with the steam baseboard plus just one radiator on the ground floor (1900 sq ft), and six radiators on the second floor (same size). We are currently 6 radiators short, in all.Ever since the re-installation and cleanout, we have had a problem with the boiler shutting off unexpectedly. To get it to re-start, I have to use the blow down valve to drain some water from the boiler. When the water level goes down, the boiler starts. So I assume that the high-water cutoff is being activated. When I open the valve the boiler starts right away, but if I close it too soon it immediately shuts off again. Removing about 2 gallons usually gets it going properly. In most cases I can draw off about 5-8 gallons of cold water before the valve starts spitting. When the boiler is operating normally, when its hot, only about one gallon comes out before it spits.After I drain it, the system works fine for a period of time, from six hours to three weeks. In fact it has been working fine for about 3 weeks, but yesterday it shut down late in the day. I drained the boiler and it fired back up, but it was off again this morning. (The weather has been unusually warm, so we havent been running the system as much as we normally would, in Michigan in December. But it ran a lot during the last two weeks.)Heres what appears to be going on. Steam is going up into the system, and the auto-feed valve is adding water to the boiler to compensate. (The valve is less than 2 years old, and I have seen no signs that it is sticking, but I guess thats possible.) The whole time that Ive lived in the house Ive heard the valve thump many times per day during the heating season, so I assume this is normal. This cycle continues until the house comes up to the right temperature, and the thermostat shuts off the boiler. Then all of the steam condenses and drips back down, over-filling the boiler. It never comes back on.To try to fix the problem, the plumber came back and cleaned out the boiler again, using the same chemical, and then again, using a different chemical and some apple cider vinegar. A lot more rust came out, both times. (The water in the sight tube is relatively clear now.) I thought that the problem was fixed, until last night.I spoke to the Utica Radiator company, and they suggested that we install a delay device on the auto-feed valve, so that water will have a chance (1 minute?) to drain back down before the valve adds new water. I dont like that solution because it doesnt address the cause of the problem. The system worked great for years. What changed? Why cant we simply put it back the way it was, instead of putting a band-aid on the problem with the delay unit? Could the plumber have accidentally damaged or misadjusted something? Clearly, something has changed. We want to go out of town for the holidays, but now Im afraid to leave the boiler alone. If it shuts off, the house will freeze.Help!– Eric Pearson, Huntington Woods, Michigan

[Eric PearsonParticipant]

It has been years since I have worked on a steam boiler, but I have never installed a high water cutoff on one. If you are opening the drain on a McDonald Miller 47-2 or 51-2 unit, then it is working backwards and the burner may be connected to the electric feeder or alarm circuit. When you blow it down, it is supposed to simulate a low water condtion and turn the burner off (not on), until the water reaches the operating level again.: I apologize in advance for the length of this question. I dont know which facts are important, so Im including everything that might be pertinent.: My house was built in 1927, and the Utica Radiator Company boiler is about 20 years old. It is a gas-fired, single-pipe steam system, and it has been working very well for the three years that I have owned the house. The previous owners told me that it had been very reliable.: The previous owners removed two radiators from the ground floor, and capped the pipes. The living room and entrance hall (about 1/3 of the ground floor, in all) were converted from radiators to steam baseboard. A huge radiator in the garage was also disconnected, two owners (50 years?) ago.: Several months ago, my plumber removed all of the radiators from the house, and we had them dipped to remove interior rust and exterior paint. (The steam baseboards were not removed.) The radiators were then powder-coated, and all of the vents were replaced, before the radiators were re-installed. Some of the valves were also replaced. We have been checking for leaks, and havent found any.: When he re-installed the radiators, my plumber recommended that the boiler be cleaned out with a powdered chemical of some sort. He did so, and at the same time he installed a cleanout on one of the pipes, right at the boiler, to make future cleanings easier. No other mechanical work was performed, as far as I know.: It may also be important that, while the renovation is taking place, we have temporarily removed and capped the radiators in the kitchen and breakfast room, plus the large bathroom on the second floor. One radiator on the second floor is turned off at the valve. That leaves us with the steam baseboard plus just one radiator on the ground floor (1900 sq ft), and six radiators on the second floor (same size). We are currently 6 radiators short, in all.: Ever since the re-installation and cleanout, we have had a problem with the boiler shutting off unexpectedly. To get it to re-start, I have to use the blow down valve to drain some water from the boiler. When the water level goes down, the boiler starts. So I assume that the high-water cutoff is being activated. When I open the valve the boiler starts right away, but if I close it too soon it immediately shuts off again. Removing about 2 gallons usually gets it going properly. In most cases I can draw off about 5-8 gallons of cold water before the valve starts spitting. When the boiler is operating normally, when its hot, only about one gallon comes out before it spits.: After I drain it, the system works fine for a period of time, from six hours to three weeks. In fact it has been working fine for about 3 weeks, but yesterday it shut down late in the day. I drained the boiler and it fired back up, but it was off again this morning. (The weather has been unusually warm, so we havent been running the system as much as we normally would, in Michigan in December. But it ran a lot during the last two weeks.): Heres what appears to be going on. Steam is going up into the system, and the auto-feed valve is adding water to the boiler to compensate. (The valve is less than 2 years old, and I have seen no signs that it is sticking, but I guess thats possible.) The whole time that Ive lived in the house Ive heard the valve thump many times per day during the heating season, so I assume this is normal. This cycle continues until the house comes up to the right temperature, and the thermostat shuts off the boiler. Then all of the steam condenses and drips back down, over-filling the boiler. It never comes back on.: To try to fix the problem, the plumber came back and cleaned out the boiler again, using the same chemical, and then again, using a different chemical and some apple cider vinegar. A lot more rust came out, both times. (The water in the sight tube is relatively clear now.) I thought that the problem was fixed, until last night.: I spoke to the Utica Radiator company, and they suggested that we install a delay device on the auto-feed valve, so that water will have a chance (1 minute?) to drain back down before the valve adds new water. I dont like that solution because it doesnt address the cause of the problem. The system worked great for years. What changed? Why cant we simply put it back the way it was, instead of putting a band-aid on the problem with the delay unit? Could the plumber have accidentally damaged or misadjusted something? Clearly, something has changed. : : We want to go out of town for the holidays, but now Im afraid to leave the boiler alone. If it shuts off, the house will freeze.: Help!: — Eric Pearson, Huntington Woods, Michigan

[Eric PearsonParticipant]

Thanks for the quick response!> I have never installed a high water cutoff on one.Interesting. I assumed that it was standard equipment. Is there anything else that would cause a boiler to shut down when too much water is present?> When you blow it down, it is supposed to simulate a low water condtion and turn the burner off (not on), until the water reaches the operating level again.That is what it is doing. If the burner is on, when I blow it down it goes off until the auto-feed valve replaces the water, at which point the burner comes back on. Sorry I wasnt clear.– Eric

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