10 story building open hot water system need advice

mikedo

I'm working in a large 220 unit 10 story building the heating system has an open to the atmosphere tank on the roof. they are having problems with sediment. it is 50 plus years old. I'm not that experienced with a system this big. is it common for the system to be open to the atmosphere. i am looking to consult with someone who has more experience than myself on troubleshooting this. not looking for free advice I'm willing to pay an expert for advice even just for a phone consultation . I'm a licensed contractor in ct building is in bridgeport ct

EBEBRATT-Ed

Open systems that are 50 years old are going to have rust and sediment, that's why most all hot water systems are closed. I have never seen an open system that large only residential on the heat side.

I had a similar situation wit a chilled water system that originally used river water and was converted to chilled water. They converted it to a closed system, installed strainers and used water treatment. It took 2-3 years of operation to straighten it out. Some times the strainers plugged up more than once a day.

Some piping had to be taken apart and cleaned, leaks fixed, air handler coils changed . It was a long procedure and cost a lot of $$$. But this system had 10" pipe. The cost to repipe in occupied areas was not an option.

Funny thing is the engineer recommended not trying to reuse the system, the owner wouldn't listen.

Yours may not bee as bad. You might rempve a few sections of pipe in different areas and take a look.

But then, winter is coming

mikedo

thanks for the advice. complicating the matter is the building has no isolating valves. also the fiberglass insulation is way past its life span and the steel piping is rusted very badly in places. mains are 6 "

nicholas bonham-carter

What sort of sediment is this? Where does it collect? What type of boiler is there? How is the tank prevented from freezing in winter?—NBC

JohnNY

I've dealt with this on larger buildings where we had to flush the system for a full day with a pump and then add a rust inhibitor/water conditioner to the system. Y strainers are too often ignored. Water treatment is sometimes, but not often in my experience, necessary to keep this at bay.

mikedo

sediment looks like mud. its collecting in the farthest riser from the boiler. 3 camus boilers. tank is on roof in a electric heated room. there are no valves to flush system properly

nicholas bonham-carter

Is it magnetic, or organic?--NBC

EBEBRATT-Ed

Sludge is not good with Camus I wouldn't think. They don't hold much water, a little sludge in those and they will go bye bye

mikedo

i never thought to check with a magnet thats a good idea thanks

nicholas bonham-carter

I suspect a combination of organic slime, and some rust. Possibly, lye could break down the organic component, and enable a good Pressure wash cleaning.
Can the roof tank stand any pressure?
Once everything has been cleaned out, the tank could be sealed up and a charge of nitrogen put in, as a cushion above the water. You may only need 5 pounds of pressure.—NBC