Kriebel Vapor vacuum systems

Butch Hobby

I am a plumbing and heating salesman for a wholesale supply
in upstate NY. I have about 35 years in the business. Recently, one of my customers asked that I go look at a 2 pipe steam system in an big stone house. It seems that the problems that the homeowners were having were water hammer, mid-cycle; some radiators not heating; and controlling the water level in the boiler. Through out the years there have been several different contractors working at this house. The system is a Kriebel Vapor Vacuum
with a still hooked up vapor/vacuum controller and a system seperator in the basement. There are about 45 radiators on the next 2 floors. Most if not all of the radiator supply valves have been changed to DanFoss TRVs and most of the return ells are the baffler ells that were originally on the system. The Weil Mclain steam boiler has 2 pressuretrols and are set at 5lbs. My questions are as follows: 1) Shouldn't there be a vaporstat instead of pressuetrols ? 2)Are DanFoss TRVs supposed to work with this system? If so, do you change the baffler ells and if not where would someone buy the orifice supply valves and baffler ells that were original to the system ? Any help would be appreciated. Thank You.

Steamhead (in transit)

First, crank it down!

5 pounds is way too high for this system. It's probably causing water to stack up in the drips, and when the steam main starts to fill with water it will bang. The ones we work on run at a few ounces. Put on a Vaporstat.

If you find you can't get steam to flow at these Vapor pressures, you have an air venting problem. The vapor-vacuum controller can be adjusted to open wider, or can be replaced with several large main vents such as Gorton #2. Also, if the steam mains are not well vented, vent them too.

If you lower the pressure and still get mid-cycle banging, the wet returns may be plugged. If so, replace them.

Aside from the bafflers, the Kriebel is basically an orifice system. You would not necessarily need to abandon the TRVs. If the system is out of balance, you can get orifice plates from Tunstall that you can drill to the proper size. These would most likely be used on the smaller radiators, and are installed in the union connection of the TRV.

What I'd do is run the boiler with enough ounces of pressure to get the largest radiator about 85% full of steam, then orifice down any radiators that filled to a greater percentage.

The bafflers should be left in place. If any radiators don't heat, however, it might indicate a baffler that is stuck closed. Disassemble and clean the baffler to fix this.

Is the system still running with gravity (non-pumped) return?

"Steamhead"



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Jamie Hall

Indeed

before you do anything else -- anything at all -- you have to get the pressure down. You won't even be able to diagnose any of the other problems until you do. A vapourstat, and make sure the pigtail is clear (or use a new one); I'd say no more than 9 or 10 ounces max. pressure.

Then you can start finding out what else is amiss.

The TRVs can be used, yes. However, do be aware that if there is a significant number of them, and the radiators they are on are not orificed down properly, and they close, the system will probably short cycle rather annoyingly, as the boiler will be oversized for the remaining radiation. Much better to get it balanced as well as you can with orifices as required, and then if you really need them, use the TRVs.