Boiler works with no water pressure? why?


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Old 12-12-11, 02:22 AM
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Boiler works with no water pressure? why?

Hello,
My boiler is driving me insane. its a year old oil boiler used to heat the house and hot water. It seems to work when there is no water in the system. the auto filler seems to work but over fills by a little for some reason. I tried to shut the water to the boiler and keep the water in the closed system and it didnt refire and has gone back down to no heat. i am so lost and confused
 
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Old 12-12-11, 02:35 AM
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Basicly I think i have some weird problem with the water pressure for some reason. I dont know why it shouldnt be working even if i turned off the water to it. IF i turn down the main water it goes down to zero pressure. If i turn down the cut off valve to the burner it just doesnt refire. It makes no sense at all to me. help
 
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Old 12-12-11, 03:30 AM
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Timothy0001; I would fill the boiler until the pressure gauge , hopefully accurate reaches 25psi shut the feed water main valve ,close the valve to the expansion tank, shut the power supply off and then watch the pressure to see if you have a system leak it should show up quit quickly, depending on the size of the leak.
 
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Old 12-12-11, 06:01 AM
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Saves wrote:

the pressure gauge , hopefully accurate reaches 25psi
I believe he is A55uming that you have a HOT WATER system, but your description sounds to me as if you are speaking of a STEAM system?

Please tell us the make and model of the boiler and if this is STEAM or HOT WATER before you do anything else.

If i turn down the cut off valve to the burner it just doesnt refire.
Which valve? are you cutting off the fuel oil supply to the burner? Is it a small diameter tubing? Don't do that.
 
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Old 12-12-11, 03:41 PM
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the pressure gauge seems to be working fine. its a burnham v8 and the block was replaced last year. its not a steam system, i am pretty sure its hot water system bc the hot water goes thru the floor boards. I can hear the water go thru them but the pressure seems to be wrong. The valve i was messing with was the water coming into the system. I turned it off bc the pressure was getting pretty high and the pipes were knocking a bit. the auto fill valve seems to be working kind of? it starts filling with water even if the system is off. thanks for any help you can give me
 
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Old 12-12-11, 03:50 PM
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If you can hear the water going through, that usually means there's air running through also.

If you put water in the system and raise the pressure up, then close the fill valve and the pressure drops to zero, it means there's a leak somewhere.
 
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Old 12-12-11, 04:00 PM
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Your system should have a min pressure of 12 psi when the water is cold. What pressure does your system have now and what is the water temperature? When the system is running, how hot does the water get?
 
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Old 12-12-11, 04:03 PM
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everytime the boiler fires back up it fills with more water for some reason and the pressure gets pretty high. like 25psi hot and its a pretty small house then after a while it stops firing and basicly turns off for some reason. even when i had the psi at 18 by messing with the auto fill and the pipe that lets water out. it wouldnt refire after like 3 times. when it fires up to start there seems to be no air in the system. i tried to bleed it and it was just constant hot water with no air and that didnt seem right to me. maybe i cant figure out how to close the system and new water keeps getting in?
 
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Old 12-12-11, 04:08 PM
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when i turn the main water back on it fills to about 15psi and then it heats up to about like 20-21 but the auto valve puts more water into the system when it refires and can get to like 25-30. i mean maybe its the auto fill valve or maybe i should wait until the system is completely off with no water pressure and no heat. the system gets to about 180 and refires at about 160 so i think thats fine. just this water is annoying and it seems to work best when there is no water in there at all. makes no sense
 
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Old 12-12-11, 04:30 PM
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What do you mean by "when there is no water in there"?

At any rate. I think you need to learn about boilers a bit. It was good when you boiler filled up to about 15 psi. That number is just fine. That's when it is cold. Now, when the boiler heats the water up to 180, the pressure will increase to about 20-21 psi as you had stated. That is normal operation. When water is heated, it expands and that is what is causing the pressure increase. Now, when you say it went up even more to 25-30, that's an indication of a problem. More water is not coming into your system. It is the expansion of the water due to thermal heating that is increasing the pressure. There is a device on your boiler system to deal with this expanion and to keep the pressure under control. That is called an expansion tank. Most systems have something that looks like a propane tank on them. That would be the expansion tank. Older setups may have a steel tank up near the ceiling. Let us know which you have because the problem you are experiencing is indicative of an expansion tank problem. If you have the propane tank looking one, it needs to be replaced. If it is the other, we can tell you the specifics of getting that fixed.
 
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Old 12-12-11, 10:58 PM
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when it fires up it goes to about 15-20psi when its at 180 degrees its at like 20-25psi and it wont refire. when the water pressure is at 1 or 2 psi it will refire for about a day and then shut off. im pretty sure the expansion tank looks like a propane tank, its metal and like a big metal donut. I just dont know why it would keep refiring when there is very little water at like 1 or 2 psi but wont when there is 20 psi in the system?
 
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Old 12-13-11, 03:44 PM
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Replace your expansion tank.

You should have a min of 12 psi when the water is cold.
 
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Old 12-14-11, 03:30 PM
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I talked to my friend who is a professional and he said that it needs to be cleaned. the reason it keeps turning off is the nozzle and filter keep getting clogged. as for the auto fill valve maybe it has to be adjusted back to 15psi or maybe it could be warn out bc it hasnt been replaced for a very long time. does this seem like the correct answer? it hasnt been cleaned in a while. i guess when they put the new block in they forgot that part lol
 
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Old 12-18-11, 08:10 AM
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DO YOU HAVE A CIRCULATOR on the boiler if so there are no limit controls between the water feed or pressure to the actual cycle of the oil burner....unless you have ZONE valves with end switches.the temperature control on the boiler will fire with or without water thats why as said they have a 12PSI RED auto feed assembly at a cold boiler that heating up and temps is good 180F/20PSI and the stat is satisfied.if your dropping pressure without any heating you have a leak...the banging and water noise is air in the piping...leave the circ off shut off servcie switch..maunally open the zones valves and bleed from the highest point....the RED feeder will feed 12lbs into the boiler and piping to push the air out.....if the water is hot you can still bleed just shut the boiler off..NO CIRC..zones open positions manuall push bars
 
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Old 12-18-11, 09:40 AM
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Smink, for the sake of clarity... can you please explain to the audience what is a

"12PSI RED auto feed assembly"

Do you mean a "12 PSI pressure REDucing valve" ?
 
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Old 12-18-11, 03:06 PM
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it's the only thing painted RED mounted on the copper water line and feeds water into the boiler and maint 12PSI factory set.if you don't have on then you have to maually fill the boiler..to 10-12 PSI
 
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Old 12-18-11, 03:27 PM
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But only the Bell and Gosset are RED, and some of those are GOLDish... Taco is GREEN... Watts is kinda BROWNish... all pressure reducing valves are not the same!
 
 

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