Purging air from my oil burner


  #1  
Old 11-08-01, 05:37 AM
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Hi folks I just came across this Sight about 5 minutes ago while searching for, well, an oil burner forum.

Anyway, I have an older Weil mclien burner, My water is starting to get hotter then the shutoff calls for, my first guess at the problem is the Aguastat. I bought a new one and I'm going to do it this weekend. My question is: Aside from turning off the Raw water in and draining the burner, Can I/should I turn off all the ball valves that send water too and from my heating radiators? will this keep me from emptying my whole house? Will it be easier to purge my system when I finish the job and start letting water back into the burner?
While I'm shutting down the system, I will check the screen in the raw water pressure valve...Good idea?

Thanks in advance This sight looks like a friend to me. I do everything myself.
 
  #2  
Old 11-08-01, 06:14 AM
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If your system has no zones, to purge system of air;

Turn off power to system.

Close gate. This is the shut off valve usually located on the pipe that brings the water back to the boiler from the radiators. Usually the circulating pump is located below the gate.

Open tap. This is found usually directly above the gate. Drain system until system is purged of air. Then close tap.

Open gate and turn on system.

When you are draining water from the tap, water is being feed into the pipe that brings water to the radiators to replace the water that you are draining. This movement of water is designed to flush out the air that may be in your pipes and/or radiator through the tap.

If you have zones, there are just a few more simple things you have to do. Let me know if you do by posting a reply.
 
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Old 11-08-01, 06:34 AM
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YEs I have 3 zones. I have a pair of valves above each circulator they are the returns. So I will shut those off, shut off the valve of fresh water in, open up valve at bottom of boiler. let it drain down low enough to replace aquastat. Now, Do I turn on fresh water valve and let boiler fill until it stops filling then open up the Return valves??
 
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Old 11-08-01, 07:29 AM
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Let us use the same terms so we can communicate better. A GATE is a valve that stops the water from going through the pipe. A TAP is a valve that you drain water from. The aquastat and the boiler has very little to do with purging the system of air. It is done to remove air from your pipes and radiators. In most cases the purging of air bypasses the boiler. The reason for this is air bubbles in the water tend to rise to the highest point in your system, pipes and radiators. What you described leads me to believe that you have two pumps and three zoning valves. Therefore one of the pumps is serving two zoning valves. This is not an unsusal set up. In order for me to tell you how to properly bleed your system of air, I NEED YOU, to descibe your boiler set up to me. All hot water heating systems are closed loops. What this means one pipe send water from the boiler to the first radiator and on to the next radiator, then a separate pipe sends the same water back to the boiler from the last radiator on the loop. When you have three zones, you have three separate loops. To purge air from a three zone system, you have to do it one zone(loop) at a time. You have to describe to me where all the gates are, there should be six. You may have two or three taps. The pipe that comes up from the top of your boiler should split into three pipes with zoning valves and gates before or after the zoning valves. The pipe that has the pumps, one pump should have a pipe that splits into two pipes with a gate and a tap on each one. The other pump will have only one pipe to it with a gate and tap on it. You are always looking at the pipes that are going away from the boiler and not towards the boiler. Take your time, this sounds harder than it really is. I am certain you can do this. The hard part is doing it over the net.
 
  #5  
Old 11-09-01, 12:39 AM
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If your aquastst is located in the boiler, do your best to isolate only the boiler and do not drain. Thats correct, do not drain. It's not necessary to shut off everything you see just the area your working on. Once the boiler is isolated releive the pressure by opening a drain valve or temperature/pressure relief valve. Prepair your new aquastat for installation. Have it and any necessary tools right next to you ready to install. Slowly remove the old stat releiving any additional pressure that has built up then as quickly as possible swap them out without dumping any more water then necessary. Once completed very slowly crack open one of the valves used to isolate the boiler allowing it to build pressure while at the same time open the temp/pressure relief valve to purge as much air as possible. Once you've built full pressure, fully open the temp/press relief to remove any additional air that might trap hi in the boiler. (you will hear the air bubbles crackling through the relief valve) Open all valves origionally closed and again purge through the temp/press relief. Wire the stat and start the pump (leave boiler off). If you have a bladder expansion tank with an air scoop on top, purge the air scoop. The air scoop will look a little odd shaped but is usually cast iron, heavy looking and has the expansion tank hanging from the bottom middle. Make-up water may be piped into it also. Do not attempt to purge from the bottom of the tank, only the top of the air scoop. Allow the pump to run for awhile then bleed air from the radiators. Restart the boiler, then once heated, again purge air from all areas mentioned above. If after a few days you hear a bubble or two passing through the radiators, purge them again.

The idea is not to make the job harder than necessary. If you drain the boiler un-necessarily you'll spend hours back and forth purging. Air doesn't simply go to the bleeds. It traps until the bubble is absorbed or broken up and moved along to the bleeds. It can be, in some cases, very time consumming to remove.
 
  #6  
Old 11-09-01, 01:05 AM
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The ole quick-swaparoony.


Thanks all.
 
  #7  
Old 11-09-01, 02:04 AM
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I suppose you could dump the entire system and make a real job out of it. Frankly I'd rather be on the tennis court!
 
  #8  
Old 11-09-01, 03:24 AM
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Talking

I may burn my fingers, this sounds like a job for the Wife.

Just kidding...thanks again
 
 

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