two pipe steam

William J. Rella

Many years ago it had three coal fired boilers (vacuum steam) that were replaced with one HB Smith converted to two pipe steam.
This summer we replaced the HB Smith with a Burnham V909A, (4200 sq.ft.) with Beckett CF-2300 burner. The new boiler has been skimmed several times and chemically treated so both the water in the boiler and the steam are clean. I have a Vaporstat controlling it set on just under a pound and cutting in at 6 oz.
The problem is while making steam the boiler water leaves the boiler and goes into the system and starts a short cycling situation. If we leave the 47-2 feeder/lwco controlling the water line, the boiler floods. If we leave the feeder disconnected it will short cycle and eventually trip the manual reset in the M/M #63M lwco. Today we are checking the returns to see if they are full of mud, therefore slowing the condensate return. I don't want to install a boiler feed tank and remove all the F&T traps until I'm positive I need one. Any sugesstions?

Ken_40

The chemicals you added...

are what?

We found automatic feeders to be inherently problematic. The reason?

They are on timer pumps. The timers are set at a specific interval of say twic e aday, for say 30 seconds pump/run time.

In fall, the pump puts in the same amount as dead of winter; resulting in huge overdosing and the resulting priming and srging you now experience. In dead of winter, that same pump rate will leave the boiler vulnerable and corrosion will accelerate.

The solution? Stop plugging the chemical feeder into the wall outlet and tie it into a spare relay contact that will only actaute the feeder when the boiler is on!

You have no feeder? No problem. Dump half the water in the boiler, don't add anymore chemicals and see if it quiets down. If so, you have the wrong chemicals or too much of the right one.

I urge you to dump the entire boiler, fill it with clean water, add 1 cup of TSP per 100,000 BTU's of input, almost let it steam, dump and then rinse the TSP and see what happens with no chemicals or detergents in the system.

If the water is stable without bounce or LWCO fake out, the problem is certifiably too much chemical or the wrong one.

Let us know what develops. Show this post to your chemical guy. If he doesn't "understand," find a new chemical guy.

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Matt_67

Short cycle

A condensate recever may be your only choice if your returns are clean and the water line steady. The time it takes to return condensate is the issue and what drives the need for a tank. Make sure the returns are clean and waterline not surging as you planed. Then you have to evaluate the need again.

Steamhead (in transit)

Did the system

have a vacuum pump originally?

If so, that's what you need because the pipes were sized for vacuum-pump operation.

But if it was always gravity return, with no pump of any type, you more than likely do NOT need a return tank and pump. Many times these are installed where they are not needed, and they add moving parts and service headaches to an otherwise simple system.

If condensate is slow to return, find the problem and fix it.

You mention "removing all the F&T traps": are these traps original to the system? If not, when and why were they added? If they don't belong there, they may be contributing to the problem.

If the boiler is not piped correctly, the steam may be pulling boiler water out to the system. Extremely dirty boiler water can do this too.

"Steamhead"

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