Hydronic Boiler won't start on own & shuts off too early

I have a Mini-Therm hot water boiler that no longer comes on when the thermostat calls for it. I have to push an ignition button each time including ~4am when the temp in the house goes below 62 degrees. The boiler also shuts itself off before the desired temperature is reached and I have to manually restart it each time. This has ended up being about 10+ times a day during really cold weather and is getting tiresome.
I've also noticed the water pressure is only at 15 psi. Isn't it supposed to be at 30 psi?
I've bled all of the upstairs radiators with the boiler on (which is what the previous owner told me) and got a small amount of air out of each one but when I opened one of the radiators in the basement, there was no valve to bleed it. I stopped at this point since the other 2 radiators downstairs are currently painted shut.
Any suggestions? Where should I start?
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snipped-for-privacy@earthlink.net wrote:

Not having the slightest idea of what sort of burner you might have, the first step would be to call your local oil or gas service, and get a tech out there before you do some major damage by hitting a reset.
And ask him/her the questions.
John
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Agreed, there are numerous possibilities, the least of which includes the thermostat or circulation part of the system. It sounds like a combustion problem which is best solved by a tech with proper equipment
wrote:

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Get a pro out for the ignition issue, I only run 12 lb on a 3 story house, you only need to get water to the highest radiator , you may not need 15lb
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It shuts itself off because the internal water temperature is up to where it should be. The thermostat controls the circulator, an aquastat inside controls the burner so it does not overheat. It should cycle off and on as needed.
There are numerous reasons it will not start. Is it oil or gas fired? Each has a different set of problem. It may be something as simple as cleaning the igniter or more complex as a fuel pump. If you have no clue how these things work, call a serviceman and let him do it.

15 psi is plenty

That is not your problem here.

Call a service tech.

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It is a gas fired boiler. The past couple of days it has been coming on by itself in the morning which it hasn't done in awhile, but it still does not stay on long enough to bring the temperature in my small living room up to 68. When it shuts itself off, the water temp seems to drop pretty fast but then it doesn't come back on. We are going to try cleaning the sensor near the pilot light first then call a serviceman if that doesn't work. Thanks. At least I know that it isn't a water pressure problem.

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Just wanted to update you on the problem. A service tech came out and found that the gas pressure going into the boiler was a little too high which was causing the safety switch to trip itself. He adjusted the pressure and it has been working perfectly since. Easy& cheap fix.
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