Fargo Steam Boilers

Supply House Rick

if there are any horizontals in the return just above the waterline the condensate could be hidden in there, as the boiler fires, and builds even the low pressure our systems thrive on.-nbc

Steve C

Steam boilers

Gentlemen,

I have 2) 100hp Burnham sectional boilers installed in a 71,000 sg ft School. The problem I have is when I start the boilers cold they trip out on low water cut off. once I get the building warm they start to cycle on the pressure controls. About a hour after starting them here comes the condenstate back dumping about a 100 gals of water and chemical on the floor any ideas?

Steamhead (in transit)

Several possibilities

There may be vacuum holding water up in the system, or the return lines are sluggish, or (if it's a 2-pipe system) bad traps.

How about some pics?

"Steamhead"

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Steve C

Fargo Steam

There mite be a trap left that has not been rebuilt. I think we have got all of them.

More Info

Burham Model V1117 Natural Gas / oil # of sections 17
Gorden Piatt Burner
M# R10.1-GO HP 2

Boiler Feed Pump & Receiver
Hoffman 200HBF (SO)-2525
12.5 GPM
25 PSI
Tank Size 220
Motor HP

I think that the boilers are to small for the load. If I shut off the steam to the newer addition converter. Steam builds faster and I do not have so much water bounce in the site glass. Because the system puts water on the floor on cold start up I think the tank is too small.

My co-worker thinks that the condensate pumps are to small.

The way the Building Eng keeps the boilers running on cold start up is to mannually control the feed water pumps until the boilers start cycling on the pressuretrols.

We are adding on to the building two more heat exchangers and I Am afraid that the problem will get worst.

bob young

Steamhead (in transit)

Instead of using heat exchangers

why not a dedicated hot-water boiler for those zones?

Have you counted up all the steam radiation and compared it to the boilers' ratings

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Steve C_2

Fargo steam

Our Mech Engineer claims to Have.
In talking with a former building enginner condensate return has always been a problem.

ttekushan_3

According to my calcs,

the pumps are adequate. The 200 HBF is large enough for 180 HP. You have 200 HP. This doesn't explain the phenomenon you describe, however. Each pump is good for 25 gpm. I am presuming you have the duplex unit with one pump for each boiler, both mounted on the 220 gallon tank. The boilers can produce about 3350 pounds per hour or so, requiring only about 7 gpm if run continuously. The pumping rate is adequate.

If the condensate takes an hour to come back, your receiver has to be 4 times what you have. Obviously, this is excessive. So where does it hang out for an hour? What could it possibly be doing?

A few things come to mind:

Since this is undoubtedly a two pipe system, has anyone added vents at the end of the mains or on radiators/convectors? The reason I ask is that if the return lines have poor pitch, the air flow through the proper return channels should assist the condensate return flow, unless vents were added to deal with slow heating of the affected areas. The condensate can then linger.

Are there any strainers that have not been cleared recently?

Are there any condensate transfer stations that are not properly vented? If there are condensate stations and they are vented with a line that returns to the boiler room, then we are dealing with something else.

The something else: Is this system supposed to have a vacuum condensate return system? If the system was originally conceived with vacuum return, then the condensate can hang out there for a very long time. There are vacuum condensate pumps, vacuum boiler feed pumps, and stand alone vacuum pumps which can be used in conjunction with an existing condensate pumping arrangement.

I am currently putting a quote together for restoring the vacuum to a Webster vacuum/ moderator system. Most of the moderator components are gone, but the 1936 vintage nash jennings vacuum pump worked until several years ago. A standard condensate pumping station was put in its place. At that point, the system began doing what your system does, flooding the receiver after a long return delay, dumping the overflow on the floor. They added a second tank, but that also floods. This may not be your situation, but vacuum return is common in school heating systems.

-Terry

The Steam Whisperer (Formerly Boilerpro)

I have a Nash Jennings' Rep nearby

if you need a contact

Oak Services
1 888 853 9963

Boilerpro

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tim smith

My guess is the system is spread out enough that all the

steam goes out to system, heats building up and then all that condensate comes back with boiler not calling anymore so needs no more water, water storage not near what it was with original boiler. Need more condensate storage. I would bet the old boiler had 4x the water storage the current boilers have. Probably old firebox boiler was in there. Might need 200 gals of storage to take up excess coming back. Just my thought from jobs I have done. I bet this had gone on ever since new boilers were installed. Tim

ttekushan_3

thanks boilerpro

I'll give them a call and describe the failure. I can't believe how this old unit is built. There's nothing on it that doesn't weigh a zillion pounds!

Terry