How to reduce pressure on gas fired boiler?

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Old 12-16-13, 04:57 PM
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How to reduce pressure on gas fired boiler?

A couple times each winter I have to purge the from the heating zone on the 2nd floor of my house so I decided to increase the pressure on the boiler hoping that it would fix the problem. Pressure on the boiler was around 12psi when the boiler was hot. After doing some research I decided to try to get it just under 20 (like 18ish) hot.
I unscrewed the nut on the feed valve (dont know the technical name for it) and turned the screw clockwise to increase pressure. Problem is I guess I turned it too much because the pressure kept climbing. It got to about 30 and I shut down the boiler. So now I'm trying to figure out how to reduce the pressure. If I back out the screw on the feed valve it doesnt do anything. I'm assuming that I need to reduce the pressure on the boiler. There's a red valve/spigot on the boiler with a hose connection at the end. Can I just drain some water out of that until I get to the right pressure? Should I do it when the boiler is hot or cold? Any other tips you can give me?
I appreciate the help!
 
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Old 12-16-13, 05:44 PM
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I thought we covered this in another thread Frank? I'll look ... maybe you missed some replies?

Pressure on the boiler was around 12psi when the boiler was hot
Right there is a problem to start with.

The pressure on a COLD boiler should be 12 -15 PSI for a 2 story home, slightly higher for a 3 story.

When the boiler heats up, you build some pressure above that because the water expands as it is heated.

As you have learned, turning up the pressure regulator was NOT the correct thing to do.

You need to get to the ROOT CAUSE of why you have low pressure in the system to start with.

If I back out the screw on the feed valve it doesnt do anything. I'm assuming that I need to reduce the pressure on the boiler.
Yes, that is correct.

There's a red valve/spigot on the boiler with a hose connection at the end. Can I just drain some water out of that until I get to the right pressure?
Turn off the manual water shut off leading to the pressure valve. Drain just a little water to bring the pressure to say 10 PSI, just below where you will be setting the pressure valve to 12 PSI.

I hope you remembered how many turns you went with the screw on the regulating valve because you need to reverse what you did and get back to where you started. Then back it out another turn.

You need to come UP to the desired pressure so you want to start BELOW where you want to be.

So, the boiler is at 10 PSI, and hopefully the regulator is now set to 10 or less...

Turn the manual shutoff back on and watch the pressure gauge for about 10 minutes or so. It should not rise... SLOWLY, turn the adjusting screw clockwise 1/2 turn at a time, with a 10 minute rest between adjustments to give the boiler time to equalize the pressure.

When you get back to 12-15 PSI, slightly snug the locknut while holding the adjustment screw so it doesn't turn.

Should I do it when the boiler is hot or cold?
For this, it really doesn't matter. The pressure will drop as the boiler cools and the valve will automatically adjust for that.

Any other tips you can give me?
Before you do anything, ask here first if you are unsure about something!
 
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Old 12-16-13, 05:46 PM
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OK, I just looked... here's your previous thread... and you seem to have just dropped it and never returned for your answers. You're not going to do that again this time, are you?

http://www.doityourself.com/forum/bo...baseboard.html
 
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