steam boiler low water problem

My steam heating system has never worked properly, it was installed in the summer so shortcomings were not apparent until the heating season. its gas fired with auto low water fill by sensor. The problem is that when filled to the recommended water level, during one heating cycle it will run and the water level will go down, until the low water sensor triggers a shut off, then it calls for a fill and the system water returns in addition to the fill, now its over full, the gas restarts and this cycle repeats itself until water comes out of the radiators, the only way to control it is to shut off the auto fill.
Ive done more homework to see if the boiler is correctly sized, and it seems to be, if nothing its bigger than required, its a 150K btu unit, the house has 234 sq ft of radiator tubes (by the mclain calculator (Boiler Sizing | Weil-McLain) any rcommendations would be appreciated.
thanks in advance

 

Your boiler sounds like it is surging, possibly from dirty water from not being properly skimmed at installation. Castings have an oil film on them from manufacturing and the boiler must be properly skimmed to get rid of that oil to stop the surging and produce dry steam to the rads.

Depending what you have for an autofill there may be a timer on it to give the water a chance to equilize before adding more water.

The near boiler piping is also important. Pics would be helpful if possible.

Hope this helps a little.

 

Add water to one-half the height of the sight glass and then turn off the make-up water valve. If the low-water cut-off actuates then raise the water level in one-inch increments until the boiler no longer trips from low water. Leave the make-up water valve off and check the level daily for a week to see how fast the system is losing water. Only add water manually to the lowest level that keeps the low-water cut-off from actuating. A tight system should not need to have water added more than once a week and probably less often. Do not run the water level more than three-quarters of the height of the glass.

There are several REQUIRED maintenance items that need to be performed on STEAM boilers on a periodic basis, adding water is one of them. Another is "blowing down" (draining off) an amount of water equal to that made up on a monthly basis or more often if yuo lose a lot of water.

I strongly urge you to buy the book We Got Steam Heat by Dan Holohan and read it cover to cover. Available from many sources.

None of the above is meant to negate what spott wrote, only additional information.

 

thanks for the replies! good things to try.
Also I have to correct my description as it may be that this only happens from a cold start, I did witness proper cycling after it had been in operation for a while in bringing the house up from the overnight setting

 

Thanks for the reference, do you know if the book covers the same material as Dan's other book " the lost art of steam heating"? Ive got that one, and it was helpful.

 

Shep,
By the looks of that piping you're not the only newbie here. That piping goes against every steam principle known to man. He piped that as a hot water boiler and not steam starting with the copper pipe.

If you look in your book from Dan you will get an idea of the right way to pipe it. For that matter look in the installation manual that came with the boiler and it will show you the proper way to pipe it.

I honestly believe that the way that boiler is piped voids the warranty. It may be something to check before it's too late and not from the guy who put it in.

I'm sorry to be so harsh but when I see people paying good money for a job from a supposed professional that doesn't have a clue it drives me nuts.

 

The comments were food for thought, and I think have led to a solution, I discovered that the fill solenoid has settings which allow for dwell time between getting a fill signal and actuation of the valve. With the dwell set at 3 minutes, this gives plenty of time for the water to run back into the boiler and cancel the low water alarm signal. I watched it this AM and there was no overfilling.
W/respect to the copper piping, I looked in other forums and it seems like a controversial topic, this led me to inspect the tubing more carefully. lo and behold, there are some pinhole leaks at at lwast one joint on the header. Can these be repaired or is replacement the only option?
thanks again!
Doug

 

Shep,
They can be repaired but will probably happen again. Anyone that knows steam never uses copper on the supply lines. One of the reasons for this is the expansion of copper compared to black iron is different. Solder joints are not made to handle steam. You have other issues besides the copper such as no proper header and Hartford loop.

I put a job in a few years back and the boiler leaked within the warranty period and flooded the basement. The homeowner called me and I got hold of the company who came down and covered the boiler but said that if there would have been any copper above the steam line the warranty would have been voided.

He did say he saw a trend in plumbers starting to use copper and boilers starting to leak so that's the action they were starting to take.

The owner called his home owners insurance about the basement damage and the agent was looking for 1 thing. A Hartford Loop on the boiler which it did have. He said without it the claim would have denied.

This was just my personal experience with steam installations. Until that time I thought copper and no loop were just bad piping practices. I didn't realize they were insurance and warranty issues.