Boiler pressure rising very fast.


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Old 02-14-13, 03:07 PM
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Boiler pressure rising very fast.

Hello, I have an old weil-mclain no 50 oil boiler and the pressure rises fairly quickly past the 30 psi saftey limit. I bled the radiators, drained the boiler until the pressure is 12psi, nothing seems to be working. Can anyone tell me how to set the pressure correctly. There are 2 valves (one at botton and one at top) where i drain to bring the pressure down. Any help appreciated. Thanks in advance.
 
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Old 02-14-13, 04:01 PM
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You need to service your expansion tank. Pictures of your system will help others give you more advise.
 
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Old 02-14-13, 04:05 PM
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Hi Neil, you may have one, or a combination of three troubles with your system.

First thing though, locate your EXPANSION TANK.

Is it a large steel tank in the joists above the boiler? or is is smaller, about the size of a propane gas grill fuel tank and hanging from the pipes?

Yes, please take pictures, the more the better.
 
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Old 02-17-13, 07:04 AM
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I dont see an expansion tank...

Hello , I dont see an expansion tank but here are some pics.

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[note says: "Water is from melting snow, not boiler"]

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Last edited by NJT; 02-17-13 at 07:32 AM.
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Old 02-17-13, 07:34 AM
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Do you see any CIRCULATOR PUMPS anywhere?

This may still be an antique GRAVITY FLOW system.

Have you been in the attic? Is there a tank up there?

More info:

Hot Water Heating Systems Design
 
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Old 02-17-13, 09:36 AM
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I see no exp tank in attic.
 
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Old 02-17-13, 09:47 AM
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And circulator pumps? are there any?
 
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Old 02-17-13, 04:20 PM
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no I dont see any either. This is a very old system.
 
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Old 02-17-13, 05:13 PM
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If there are no pumps, then it is a gravity system.

It may even be an 'open' gravity system...

How do you fill it with water?

If the system is 'closed', then there HAS TO BE an expansion tank, somewhere!
 
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Old 02-18-13, 04:09 AM
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If you look at the first pic (with the belt hanging) there is this device with a lever that auto fills but if i wanted to fill up I just lift the lever and it fills to whatever pressure i want. But as soon as the boiler kicks on the pressure starts rising after 10 mins or so beyond the 30 mark. I really cannot find an expan tank.
 
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Old 02-18-13, 05:36 AM
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Have you lived with this system for some time? Have a 'history' with it? In other words, it has worked fine up to this point?

Some of the parts appear to be new (that fill valve for example)? Did you do? or did a technician do?

Are there any pipes disappearing into the ceiling? and nearby are there any 'mystery' drain valves hanging down from the ceiling?
 
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Old 02-18-13, 01:49 PM
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You have an expansion tank. It will be either a bladder type that looks like a propane tank, or a steel tank high up above the boiler some where. Here is what a stell expansion tank may look like: Re-charge a Hot Water Boiler Expansion Tank - Steel Tank
 
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Old 02-18-13, 03:07 PM
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This is a real mystery to me I searched this entire house and cant find an exp tank. Anyway, i may have to call a pro but around what should I expect to pay for this?
 
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Old 02-18-13, 03:33 PM
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You've followed all the pipes where they go?

Looked behind the sheetrock in the basement ceiling?

Checked inside the closets?

When you were in the attic, did you happen to see any pipes coming up and going over and toward the eaves of the attic?

Have you ever seen any water coming from the eaves?

Please answer the questions, we can't help if you don't:


Have you lived with this system for some time? Have a 'history' with it? In other words, it has worked fine up to this point?

Some of the parts appear to be new (that fill valve for example)? Did you do? or did a technician do?
 
 

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