Help with Water Loss

BigRedSteam

Need some help to track down the source of water loss in my boiler in NY

I am currently loosing between 8 and 12oz of water per run.
This happened at the end of last season. Never found the issue. Since the start of this heating season there has been no water loss until Mid January.

Boiler is a gas fired dunker psb7d (7 section) supplying about 420 edr. near boiler piping is correct. 2 mains loop the basement..Water is clean, system produces nice dry steam, ends of main get hot in 4 mins. Wet return new is piped in copper 4 years ago below basement floor.

• Started to notice this issue started to occur about 2-3 weeks after i started running steam master tablets.
  
• I checked all main vents (3) and radiator vents. Ruled out radiator vents since this occurs on warm days when rads don't heat all the way across, (so vents never feel steam.)
  
• no visible leaks on main pipes, valve stems etc.
  
• i finally held a humidistat below the flue intake above boiler crown. humidity went from 20% in boiler room to 60% above boiler!
  
• after burner shutoff I could hear a whistling, squeaking sound when holding ear close to sections.
  

Does the above indicate a leak in boiler? Is it possible that any holes or cracks in boiler sections corroded over during off season in untreated water and then got "cleaned" off after adding steam master and repeated boiler runs during cold snap?

Help help!!

nicholas bonham-carter

Do our favorite overfilling test: fill it up to the header, and let if sit for a couple of hours. Check the floor, and the fire box for drips.—NBC

Jamie Hall

And yes, it is entirely possible that there was some corrosion in the boiler, and when it got cleaned off it leaked. Not that one wants to count on the rust to stop a leak, but sometimes it does!

Fred

Do you see clouds of steam from your chimney, when the boiler is running? Sounds like maybe a leak in the boiler, above the water line.

BigRedSteam

I have seen white vapor on cold days..assumed it was just a function of hot exhaust cooling...would not describe them as clouds of smoke. I will look at that today..boiler filled to header currently and letting it sit for a while.

Jamie Hall

And yes, it is entirely possible that there was some corrosion in the boiler, and when it got cleaned off it leaked. Not that one wants to count on the rust to stop a leak, but sometimes it does!

BigRedSteam

NBC - flooded boiler to header Waited 2+hrs and no leaks visible on floor or in pan below burners. Boiler was still pretty warm so if there was any water from a small leak i guess its possible it could have evaporated before running down the side of the sections. It was 40 degrees here today, checked chimney for white smoke and nothing. Inspection of boiler cover (area above sections) showed white condensation on metal. Inspection of bottom of cast iron sections just above burners showed a bunch of rust, some darker than others and 2 small areas of a white deposit.

any next steps folks? shall i just take off the boiler cover in the off season?

Fred

When you say the wet return was piped in copper, about four years ago, below the floor. Was all of it replaced or just a section that leaked? If only partially replaced, it is possible another section is leaking.

BigRedSteam

it was before our ownership of the house..both sections, from end of main below waterline to termination with hartford loop are piped in copper so i assume the whole thing was done.

Fred

I assume they cut through the concrete floor to get to the buried wet return. Is the floor cut all the way from where it enters the floor (at the end of the main) to where it comes back up (at the boiler)? Is there only one Main and wet return ?
A half pint of water per heating cycle could be a leak in the wet return or something as minor as one or two radiator valves that are leaking (steaming) from around the Valve stem packing nut, a small leak at a radiator coupling or even a leak in a union/fitting on the main. Are the mains insulated? If it's on a main, the leak can steam away and never hit the floor. It takes close investigation.

BigRedSteam

hi fred..thanks for the reply...yes they cut through the floor end to end. There are two mains which drop below water line and turn into one copper return under floor as described.

I have done a pretty good look at the valve components..Mains are insulated and partially hidden. A few areas I will take a closer look at.
1) Will try the cold mirror trick on valves
2) There is wet return/drip below a bunch of risers..that i am pretty sure was turned into a dry return after previous owner replaced boiler some discoloration on that insulation
3) areas renovated like kitchen back in the day appear to be partially piped in copper..maybe a weld is bad?

will report back what i find!