Steam to water conversion, opinions please

Steamhead (in transit)

what the heat-loss is on the proposed new floor......

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tim smith

Steam to water conversion, opinions please

Ok, here I go again. Customer has old 2 pipe steam system, going to add top floor addition, wants new zone for this area, wants to relocate and replaced old beast. Would like to have mains moved for better basement head clearance. Also possibly basement zone too. Before I decide on what direction to go, I want to see what opinions are from the Steam proponents and the water proponents.

Dave_4

As long as...

the oak/teak/hardwood holes from risers are dealt with realistically, moving the main(s) in the basement is the only thing that makes converting to water viable IMO.

We did a basement re-do and the HO asked us to move the mains to within 18" of the perimiter walls (they were ~30").

The job costs a fortune, came out beautifully and he ALSO dropped the basment floor 8"! On this small NJ house he spent 11K with us to repipe the entire basement and install a new oil-to-gas W/M EG unit with tankless coil - driving basement radiant in situ/concrete floor as a separate zone. The results he felt (and me too) were a killer rec room!

The notion of steam to water conversion was verboten because of the inlaid oak floors. Inlaid as in mahognay pinstripe a foot from the walls, embedded in 90-year-old red oak flooring. He loved the steam, hated holes/plugs in the flooring where riser would have been pulled.

The cost to convert the entire home would have added another 5K. He spent the 5K on a huge plasma TV and furniture and wet-bar in the radiant 7'6" ceilinged basement.

I thought the outcome among the best choices possible. Ever seen the Giants play on a 60" TV while your feet felt cozy in a silent (except for the surround-sound) basement?

He has Guinness in the fridge, just to the left of the boiler room (;-o)

Steamhead (in transit)

It is possible

according to one or two Dead Men, to run a steam main tight against the ceiling without pitch, IF it is dripped properly. Those who say it can't be done have probably never seen or read of it being done.

There are two major pitfalls when you try to convert a steam system to hot-water:

1- the system pressure of steam- or Vapor, which is what this probably is- should never exceed 2 pounds maximum. On Vapor, 1 pound is almost always too much. On hot-water in a 2-story building you need 12 pounds- ten times that of steam- and as the building gets taller the pressure gets higher. This increased pressure WILL do a great job of finding weak points in piping and radiators, and the resulting leaks can damage the building. I've seen jobs where this has happened, it's not pretty and usually attracts lawyers.

2. Often the old riser pipes are run in outside walls. With steam or Vapor, no water stands in these pipes when the system is off so they won't freeze. But on hot-water the opposite is true.

Our company does not recommend or perform steam-to-water conversions, and will not work on a system someone else has converted.

Ken's idea of a tankless for a hot-water zone will work fine if the load is within the coil's capacity. If it's larger, a separate small boiler would serve, and could also drive an indirect water heater.



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Dave_4

Coil capacity.

All tankless coils on steamers can deliver at least 100,000 BTU's (or whatever the minimum net I=B=R rating is of the so-equipped boiler is).

This, because all coils are minimally rated to deliver 3 GPM of hot water. It takes ~ 100,000 BTU's to delivery 3 GPM of 105F water, assuming incoming water temp of ~50 (resulting in a dT of 55 degrees @ 3GPM = ~100,000 BTU)

tim smith

Conversion

Steamhead, we have done a fair amount over the years, this one will be basically a total repipe so I am not concerned on condition of pipes, most radiators will be new and any saved will be pressure tested.