steam boiler convert to a hot water boiler?

Don Perisho

I am working on a large system in a very lod building that is water hammering badly. after looking into the reasons for water hammering, I am wondering can a steam boiler be converted into a hot water boiler? It seems that many of the reasons for water hammering exist on this system. I am wondering if it may be cheeper to convert? the biggest problem is the pitch of the return pipes is insufficient and they are i n a crawl space that is 200 ft long.

EBEBRATT-Ed_5

Most steam boilers can probably be converted to hot water suggest checking with the boiler mfg.

Why not do some reasearch and save the steam system? If the piping cannot be pitched a condensate receiver may help but you need to know steam systems as you have to look at the Whole system before making any changes.

Steamhead

It won't be cheaper to convert it

and you'll just be substituting one set of problems for another. Fix the steam system. We can help you out.

Where are you located?

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Christian Egli

A pitch for vacuum

Steam is still your friend

Steam and hot water systems both use pipes. That's about the end of the similarity. The pipes of either system are very poor at operating in the other system.

The differences have to do with layout, size, pressure, expansion, flow, zoning, dirt, air pockets... At any rate, you'd have to add a return line (because the condensate lines are not large enough and not clean) and you'd want to add a supply line (because steam mains are too voluminous to allow for efficient control and reasonable response time). Plus all the radiator connections will have to be touched. Not cheap.

Every time I've seen it, it resulted in a new water system that was worse than the steam system, even in a poor state of maintenance. The only OK way to go is to install a totally new thing, and then, you're still not as well off as with a steam system in top notch condition.

About the water hammer.

An old building with long pipes makes me think you might have a system that was designed for a vacuum pump. Are there any traces where one may have stood? Perhaps an old steam operated pump. If so, restoring the vacuum with a new pump would help. The vacuum pump would also improve steam distribution and greatly accelerate the start-up time to hot radiators. Vacuum pump manufacturers claim up to 35% in energy savings not wasted on pick up.

Are the returns big enough for the radiation, according to tables? Vacuumized returns are smaller and less pitched. That would also be a clue.

Before installing a vacuum pump, the first thing to do is hunt down the faulty traps which I suspect you have a lot of since steam is getting its way into the condensate lines and is causing the banging.

That's what I would do for sure.

One more idea that will keep you out of the crawl space. I am assuming the returns are still plenty good. What if you convert the return into a wet return? then the lack of pitch would not be a problem anymore. To do that, you'll have to provide a place for the air to leave the system. Either by an additional dry return installed above ground leaving off from each drip and radiator, or by installing one pipe style air vents on each drip leg.

The limitations to the wet return is the A dimension. If you operate at very low pressure your below the floor return could be OK. The flood level is easily maintained by a false water line.

The other alternative is... good knee pads.

Best of luck and vacuumizers are cool.

Don Perisho

convert boiler to hot water

the points you made about a vacumm pump are very good. The condendate lines are only 1 and 1/2 inch on the largest line. I am fairly stupid about steam systems. I know that one of my traps (there are four) is bad because there is steam getting into the condensate pump. I am wondering if two of the return lines may be wet returns as the traps filled up with water and I assume the lines do as well when I was cleaning the traps recently. The long return lines have vents at the far end of the lines way back in the crawl space. None of the traps are below the boiler but at or above the boilers water level. The condensate tank is supplied with fresh water fed in with a 12 psi pressure reducing valve. I don't know if this is correct.When cleaning the traps I took the top plugs out (accessing the float chamber) and both of the lower traps were full of water and with the pressure reducing valve feeding the system I am sure the long condensate returns were full of water too. I know that this system was not installed correctly as there are no drip legs or strainers in front of the traps or the condensate tank. I assume that all the traps need to be rebuilt as the pipes are the same temperature above and below the traps so they must be stuck open. what do you think? Thanks Don.

Don Perisho

boiler convert to hot water

thanks for the input. I think all the traps need to be rebuilt as there is steam getting into the condensate pump.
I have cleaned the traps but do not really know how to determine if they are bad, there are four.

Don Perisho

boiler convert to hot water

thanks for the input. I am in Oshkosh wisconsin.

Steamhead

Water backing up into returns

on this type of system means either the returns are clogging up, or the fill valve on the condensate tank is leaking. If the tank does not have a sight glass on it, open a plug on the tank and see how full of water it is. If the returns are backed up but the tank is not full (which it really shouldn't be) then the returns are clogged and need replacing.

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Christian Egli

Trouble with picturing what you have

Four traps for a whole building, that's not much. Are these traps just at the point where each return pours into the condensate tank?

How is each radiator connected to the pipes? one connection or two? are there thermostatic traps?

I am thinking that someone in frustration decided to install master traps in an attempt to keep steam from destroying the pump while avoiding the job of inspecting each radiator trap.

The problem is that a master trap installed downstream of a faulty radiator trap will cause water hammer. Double trap, double bang. Now, even the master traps are broken. Master traps are unnecessary when all the other system traps work and they become evil when any one system trap is defective.

Is that your hook-up?

This means that even more than before, the hunt for the bad traps in your system will yield great rewards.

Your condensate tank being attached to a fresh water feed line would seem to imply that your tank is indeed a feedwater tank. When does the pump come on? When the boiler level is low and calls for more water, or when the condensate tank level is high and need to be purged?

You mentioned the float in the condensate tank. Is that the float that controls the pump on and off or the inlet of fresh water?

Oshkosh, that's were all the people who have airplanes fly to from Dayton. I've never been there but it sounds like a nice place.

Looking forward to hearing back from you.