I would still lower the setting further. The 'big' houses (10+ radiators) I routinely service have no more than 1 psi set on the pressuretrol and they heat easily, with no surging. It do suspect, however,there is still oils and/or crud in the system that makes steam production difficult.
Originally posted by dtlithonia1
.... I also set the pressuretrol to 2psi and the differential to one half pound. It says the differential is subtractive. That means the boiler should cut out at 2 lbs and back in at one half pound if I am still calling for heat. Is that right?
I suspect you are right casturbo. It is a fairly big 9 room house with 10 radiators. How can I tell if it's a crud problem or a PH problem and how do you measure PH? I am still getting some surging although after several flushes (with just plain water) it's not as bad as it first was. I have not used any boiler cleaner or chemicals. It also builds to about 2 lbs of pressure. I have my work cut out for me.
You can use swimming pool test strips for the pH. Nobody does that on residential boilers, unless they've messed with the water.
It'll only be off if you use chemicals, instead of water.
Don't be bothered by the mud and crud coming back. If you pull off a little water each week to get the heavy stuff out, you'll find that it gets better and better as time goes by. Don't hurry it. New water makes new oxidation.
That you're finding mud when you look for it shows how well the system has been looked after in the past.
Think "steam cleaner" when you think about the inside of the pipes. It's like the vacuum cleaner; if you don't empty it regularly, it backs up the dirt into the piping.
If you take a little bit of mud out each week, it'll come back into it, the water will clear. Don't look for a drastic overnight cure for 50 years of nonchalant maintenance. It won't happen.
One other thing I learned, early in my career. Do your boiler maintenance on Monday morning. Every time. That way, when something comes off in your hand, and the water laps at your dancing toes, you won't have to pay overtime, or wait the weekend without heat for someone to come help. Believe me. It's your money that I'm concerned about.
Oh, by the way, don't worry about "air" coming in with the fresh water. Air refills the entire system after each run cycle. 3 times an hour, usually. NOT a problem.
Dissolved oxygen is another story, which goes away each time you heat the water.
[Edited by Noel Murdough on 11-01-2005 at 06:20 PM]
All good points Noel.
Some other points to consider for the original poster.
If you are having cold radiators around the house venting is typically the problem(but not always).
If your going to check the PH be sure that the watersample has cooled down, if it's hot it will give you a false hi reading.
Like Noel said and I agree, it's doubtfull that the PH is hi. but check anyway to be on the safe side. A litmus paper will do the job for now.
Water quality is your biggest enemy, or lack there-of.
Every attempt to control 02 and dis-solved minerals(solids) goes along way, even in a simple residential system.
Start with the proper techniques and avoid any bad habits.
The system does pull in air on the off cycle and this usually doesn't pose a problem, mainly because water at 212F will not absorb 02 readily as water at 70F will.
Now! in a perfect world you would only have to fill the unit once and never again worry about water treatment. We all know though that this doesn't happen.
The best investment you can make is a water softner.
If this is a cast-iron boiler and your still pulling out dis-colored water this could be due to the fact that cast is very pourous and it will take some time to clean the surface rust off the internal surfaces.
"Crud" in a new boiler isn't surprising, most don't clean the internals good enough after installation.
You could try a alkaline cleaner(boiler cleaner) but check with the manufacturer first, if you mess up you could void your warranty.
If you decide to go that route use very little and run multiple skims, too much alkaline cleaner will cause your residual PH to sky-rocket for a number of cycles(severe foaming) and you could possibly cause hairline cracking of the boiler internals.
I noticed that the installer used Vent-Rite #75 for the main vents. I can find information for Dole and Hoffman, but not Vent-Rite. I wonder if anyone has the pressure spec for this valve. I know for this boiler there should be low pressure (about 3psi) mains.