I need schoolen' steam guys

Solid_Fuel_Man

I have been maintaining 4 school buildings in our district all with two pipe steam heat. Water treatment, steam traps, condensate pumps, rotted condensate lines that run under the floor....... These buildings were all built between 1948 and 1967. Some still have the original Smith 450mills dry-base boilers and we have replaced some with W-M commercial 88's.

School me as to why you guys like steam, seriously, I do not want to sound condescending at all. I just don't see what steam has on water. Flame suit on...........

Taylor

Abracadabra

Solid_Fuel_Man said:

I have been maintaining 4 school buildings in our district all with two pipe steam heat. Water treatment, steam traps, condensate pumps, rotted condensate lines that run under the floor....... These buildings were all built between 1948 and 1967. Some still have the original Smith 450mills dry-base boilers and we have replaced some with W-M commercial 88's.

School me as to why you guys like steam, seriously, I do not want to sound condescending at all. I just don't see what steam has on water. Flame suit on...........

Taylor

I'll start off the long list.

• No pumps required to pump hot water
  
• Smaller radiators for same amount of heat
  
• Lower pressures required in the system
  
• Won't freeze up in no power situation
  
• Lower standby losses
  
• Faster response than hot water
  
• No electricity cost to run pumps
  
• Easier to make repairs on since there's no water to drain (above the water line obviously)
  

Abracadabra

Individual control of room temperatures

Steam can do that too

Significantly tighter control of room temperatures

Dunno.. think i'd disagree with that

NO standby loss (typical mod-con with very low mass)

I'm thinking the volume of water compared to a comparable steam boiler would lead to higher standby losses. More water mass in hot water system than a steam system.

Solid_Fuel_Man

I certainly understand the dry system, and freeze protection, but the condensate is what freezes and since it's an open system there is lots of scale and rot. Also these buildings are 100,000 square feet plus and there are many condensate pumps. So steam has pumps as well, and they are scattered all over the building.

We operate up to 10psi of steam on sub zero days in the largest building.

Taylor

Jamie Hall

May I try to be somewhat even handed here? First off, all three methods (steam, hot water, and forced air) have certain advantages. Further, there are situations in which each one's advantages are sufficient to make it the only useful choice.

OK. That said.

In a building such as a school, and considering the age of your buildings, steam would have been the reasonable choice.

Water treatment should not be required for steam heating systems (it is for power generation systems). If you are treating the water, you should examine very carefully why you are doing it. The treatment, if any, should be applied only to makeup water, and there should be very little if any of that.

Steam traps were then, and are now, simple reliable devices. Unless abused, they will work for decades without any attention.

Rotted condensate lines can be a problem, granted. Hopefully when they are replaced, it will be done properly so as not to be a problem in the future (yes, it can be done that way).

Temperature control for steam involves different valves from those one would use for hot water. They are neither more nor particularly less reliable than those for hot water. Again, properly maintained they will hold as close a temperature as hydronic controls, with the advantage that steam has a much quicker response time.

It requires far less energy for pumping (the condensate lift pumps have, at most 2 psi to work against).

@Abracadabra mentioned some other advantages.

I will add one comment: steam is a little less forgiving of poor maintenance and ill-conceived modifications. We find that it is almost invariably true that a properly maintained steam system -- even in very large buildings -- will give excellent service for many decades. On the other hand, we also find that poor maintenance (particularly of the controls for pressure) or ill-conceived modifications can render a steam system inoperative. This is also true, of course, of hydronic systems, but it is my opinion that it is more difficult for the knucklehead to really sabotage them once they are installed.

Abracadabra

Solid_Fuel_Man said:

We operate up to 10psi of steam on sub zero days in the largest building.

Taylor

Why so high? This is only for heat correct?

Jamie Hall

+1 for @Abracadabra

Unless you need the steam for a process somewhere, that's about 8 psi too high at least. Even the Empire State Building and Grand Central Terminal in New York manage very nicely on 2 psi.

And if you really are running that, it's no wonder that you are complaining about traps and pumps and so on!

Solid_Fuel_Man

The steam pressure is out of my control.......another company "takes care" of that. We at this point are just contracted to do blowdowns, traps, water testing (P/T, Sulfite) I am not at all the steam expert (water and cordwoodwood/chips are my expertise). The boiler water is generally quite murky, not at all what I'm used to with water systems.

The controls are a mix of original pneumatics and some DDC mixed in. I am the control guy, but lack understanding in steam. My company is working on getting the full contract to maintain the whole of the system, it is now serviced by a national company which we all know. Why would the pressure be run so high? This is what is killing the traps by what I have read and you are telling me.

Thanks again guys keep the lessons coming.

Taylor

Abracadabra

I think your current "company that "takes care" of that" might be idiots. I have not seen a good reason for anyone to run a steam system that solely supplies steam for heat at anything over 2psi.

jmho

Solid_Fuel_Man

Ok, I will voice some of this to the district super. And find out why the pressuretrols are set as they are.

Thanks again!
Taylor

Solid_Fuel_Man

While the kids were out of school for MLK day, we were back tracing bad steam traps. Found a pile of stuck open ones and two with the needle fallen off of the Trane bellows B-2 traps. replaced with Barnes&Jones retro kits and kept on listening and pointing the infrared thermometer everywhere we could find condensate lines.

Building guy has pressure set at 6psi with 1psi diff, said that's what it takes to get steam to the farthest wing of the school. In my estimation there would be 800 feet of steam line to the las radiator/fan coil on the line from the boiler.

Very informative today spending the majority of the day just on the heating system, as I'm usually doing some control work or electrical work there.

Taylor

Abracadabra

Solid_Fuel_Man said:

While the kids were out of school for MLK day, we were back tracing bad steam traps. Found a pile of stuck open ones and two with the needle fallen off of the Trane bellows B-2 traps. replaced with Barnes&Jones retro kits and kept on listening and pointing the infrared thermometer everywhere we could find condensate lines.

Building guy has pressure set at 6psi with 1psi diff, said that's what it takes to get steam to the farthest wing of the school. In my estimation there would be 800 feet of steam line to the las radiator/fan coil on the line from the boiler.

Very informative today spending the majority of the day just on the heating system, as I'm usually doing some control work or electrical work there.

Taylor

I've been able to get steam thru 6" mains over 800ft from boiler with less than 2 psi. Sounds to me like you need more main venting. How are the returns vented currently?

Steamhead

You might need some of these:

http://forum.heatinghelp.com/discussion/142217/the-king-of-all-crossover-traps