One Zone won't heat like it should Hot Water


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Old 01-15-11, 12:18 PM
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One Zone won't heat like it should Hot Water

I have a hot water furnace (Slant). I have three honeywell zone motors. About six weeks ago the pump failed and Center Point Energy replace it. After the service tech left I noticed my basement zone did not heat very well. All three zone motors are Honeywell V8043 E 1012 motorized valves. When the thermostat for the basement is turned up it sends a signal to the valve motor to make contact. This all works. The zone valve does send a message to the furnace to fire up (sometimes). The highest temperature I've been able to reach in the basement is around 68 degrees. After about a minute the furnish shuts down and I hear the pump working. I feel hot water both in the out supply and inward supply pipe. The problem is the furnace will not continue to run to get to the desired temperature. I replaced the zone motor and the valve. The furnace continues the same behavior. A repairman came out and told me the furnace will only run when it needs to heat. This makes no sense to me. The two other zones will make the furnace run all day to get to say 72 or even 75 degrees and will ask for more heat until the thermostat reaches the goal temperature. Why does my basement zone not call for the furnace to work harder and heat the room temperature to the desired level? I know it use to heat in the basement to even crazy high temperatures because my kids have turned it up to 80 before and when I got home I had to open the windows. Could it be the thermostat? Frustrated in Minnesota. Please help.
 
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Old 01-15-11, 01:24 PM
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The burner will run only as long as it takes to get the water temperature up to the high limit as set on the aquastat. The circulator then continues to run until the thermostat is satisfied. If the water temp in the boiler drops while the stat is still calling for heat, the burner will fire to heat the water.

With your hand trace the pipes (supply & return) as far from the boiler as you can. Are they hot a good distance from the boiler? What is the temp on the boiler?
 
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Old 01-15-11, 01:44 PM
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The pipes are pretty hot going into the ceiling above the finished rooms. I located the Honeywell Aquastat Relay L8148E. I see there is a metal dial that has temp markings on it. I turned it in one direction slightly and the furnace kicked in. I can't really tell where the mark set line is. There is a spring clamp set on top of it. What should the temperature be set to?
 
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Old 01-16-11, 01:26 PM
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I posted a reply last night but it has disappeared somehow so I'll try again.

The pipes near the boiler are hot but I'm concerned this might be due to conducted heat rather than circulation. You need to check the pipes at the baseboard, not the finned part but the actual bare pipe on each end. If they are not hot, we have a circulation problem possibly due to air.
 
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Old 01-21-11, 03:29 PM
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The pipes are sort of hot at the furthest point out but maybe not has hot as they should be. How would I purge air from the basement baseboard system? It is the lowest point of the house and as far as I can tell there are no bleeder valves to open for air venting like there is on the other floors. What we basically have is one solid connection of copper pipe that runs through the baseboards to the furthest part of the basement and then a U that turns the pipe back through the baseboards to the furnace. The basement was finished in 2004. Our house was built in 1908 and the rest of the house is radiators except for some baseboard in the kitchen which I would say must have been done in the 70. That is an older baseboard that does drain valve in it. Is there a way I can get air out of the basement system?
 
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Old 01-21-11, 03:57 PM
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The guy that changed the pump or zone should come back and bleed at no charge...

Could you give us the make and model of your boiler?
Could you post pics to a web imaging host such as photobucket? Take pics close, far, clear, from all angles, controls valves ect.
Whats the pressure and temp on the boiler gauge say?

Heres you aquastat for ref.

http://s3.pexsupply.com/manuals/1287..._PROD_FILE.pdf

Mike NJ
 
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Old 01-21-11, 05:26 PM
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Pictures of the boiler & nearby piping would be helpful. You can post them on photobucket.com or similar photo hosting site & provide a link here.
 
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Old 01-24-11, 03:44 PM
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OK. So I feel real stupid now. Probably won't be the last. Great idea on your part to take pictures. Last summer I was deep cleaning the basement and wiped down all the baseboards thoroughly. In the process I closed all of the louvers. I was looking at the baseboards and warming my feet under them. All of a sudden..."Light bulb" duh.. I opened all the louver vents and guess what? The heat started streaming out. I really knew better but was so hung up on the mechanical aspects I overlooked the most obvious. The room is nice and toasty now and my furnace is still really pissed at me for making it work way harder than it had to. I share this with you so others may learn. It's the classic question.. So your computer won't turn on, is it plugged into an outlet? Thanks for your time and help..
 
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Old 01-24-11, 04:22 PM
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You are most welcome. It takes a big person to admit overlooking the obvious. I commend you.
Should anything else crop up we are here and will do our best to help.
Stay Warm
 
 

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