Steam Boiler Control(s)

Mad Dog_2

Outdoor Sensor Control. Mad Dog

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=210&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

CJN

Steam Boiler Control(s)

I work on the museum ship Battleship USS MASSACHUSETTS. We heat the ship by feeding the original steam lines (which serve heating coils/blowers)with a commercial boiler. Recently, we have decided to open more spaces and several contractors have looked at our system in order to furnish proposals for increased capacity. Two of them noticed that we were controlling the boiler with a nearby thermostat which allowed the system pressure to drop to 0 psi when it was satisfied (the thermostat was wired in series with the hi/lo pressure switches, emergency switch, low water switch, etc.) Both informed us that this setup was incorrect - the boiler should cycle on pressure. We have made that change (removed the thermostat) and there is now a remarkable difference in the comfort level within the served spaces.

I asked the question, "What do we do when it's warms up and it's no longer necessary to run the boiler?" "Have someone shut the boiler off" was the reply. Is there a way to eliminate the human element from equation and completely automate the system?

Thank you for any assistance in this matter.

Chris

Unknown

i'm no steam guy

but i do know that Tekmar Controls makes a steam control with warm weather shutdown.

look in data brochures Steam Control #269:

http://www.tekmarcontrols.com/literature.html

soot_seeker_2

Most Steam

...boilers operate the way yours originally did. When the thermostat is satisfied, the burner shuts down as does the steam.

When the thing calls for heat, the burner fires and the boiler makes stem. A pressuretrol cycles the boiler when the pressure rises exceeds what is necessary to feed all the radiators. In this manner, the burner cycles on and off.

I might be missing something, but if the boiler is always running you're going to be very warm and someone's going to be very poor.

Long Beach Ed

CJN

Steam Boiler Control(s)

Thans for your reply, Ed.

I am very confused on this issue. We were told that the most efficient way to operate the boiler is to maintain a head of steam in the system. The thermostat was shutting the boiler off and allowing steam pressure to reduce to zero. The boiler was restarting from a relatively cold state whenever the thermostat called for heat.

If we are supposed to have a thermostat, where should we place it? If the thermostat is satisfied in one area of the ship and shuts down the boiler, how will the far-reaches of the ship receive steam? Should the thermostat be situated at the extreme end of the system? How is it done in commercial or residential applications?

Again, any help on this subject is very much appreciated.

Chris

CJN

Steam Boiler Control(s)

P.S.

I neglected to mention that each "zone" on the ship has a separate aquastat/thermostat combination that controls the ambient air temperature for that zone.

J.C.A._3

I'm with Zac on this one.

I would wire all thermostats through an outdoor control. When the temperature goes above ???, the boiler shuts down.

If possible, maybe it could be taken a step further and you could have a "stage firing" set-up. Not sure if the boilers are setup that way, but Tekmar make a control for that also. Another Chris

CJN

Steam Boiler Control(s)

Hello:

I am reposting the below question - I'm afraid it got lost in the shuffle. I would be very grateful if someone could help me with this issue - I'm going nuts thinking about it.

Thanks,

Chris

"If we are supposed to have a thermostat, where should we place it? If the thermostat is satisfied in one area of the ship and shuts down the boiler, how will the far-reaches of the ship receive steam? Should the thermostat be situated at the extreme end of the system? How is it done in commercial or residential applications?"

adayton_2

Pressure going down to zero

before ALL areas (zones) are satisfied AND the main boiler thermostat is turning off means full bodied steam "volume" is not present in ALL areas (zones) at SAME TIME (so your thermostat which is probably located in a relative HOT SPOT is shutting down the boiler prematurely). What needs to be examined and adjusted FIRST is venting. Adequate venting at returns of each zone (and on each radiator if applicable) is necessary to assure large volumes of steam can FILL each and ALL of every zone. Once you have improved the venting make sure the thermostat in question is not near any radiator device OR cooped up in small area room (like the boiler room). i.e., place it in a moderate activity room a little away from the immediate vicinity of the main boiler where it can "breathe" a slightly cooler atmosphere and away from any fire breathing Dragon Heat spewing equipment...:-). Once you have "balanced" the venting so the farthest zones ALL gets nice and full of steam ALL at the same time (roughly) you will find the thermostat issue much less problematic.

PS: you might want to look into TRVs (Thermostatic Radiator Valves) to further "balance" heat distribution to some of your thorny problem zones in ADDITION to the venting. The venting is the MOST important issue to resolve FIRST.

PPS: your pressure should be ranging between 5 oz. and 10 oz steam while operating. (this on a vaporstat, 1/2 PSI to 1 1/2 PSI on a pressuretrol) it should NOT be dropping to -0- ZERO..EVER.. "This can be another reason the steam never "fulfills" all the zones. ( it keeps floundering down to -0- pressure before it gets the chance to complete its FILL mission)

PPPS: Check and clean the pigtail the pressuretrol device is mounted on.

Alfred

Boilerpro_3

Here's a stage fired steam boiler set up

CJN

Steam Boiler Control(s)

Thanks Alfred.

If the thermostat is wired in series with the pressure controls, why would pressure not go to zero? In other words, if the thermostat is satisfied (no matter where it is)it will be electrically open, thereby disabling the low pressure switch, thereby not permitting restart of the boiler until the thermostat closes again, which could take quite a while. Meanwhile, pressure drops to zero. Is there a different way to wire a boiler thermostat other than in series with all of the other boiler electrical controls?

Also, how do we reply to technicians who tell us there should be no thermostat at all?

Also, I probably shouldn't tell you this, but we run the boiler between 7 and 12 PSI.

Thanks for your patience.

Chris

Christian Egli_2

Time for a timer

The question was already answered, but I had a little time.

What should you do with your thermostat? Install it outside the ship, in the cold. Here's why:

When it gets cold, like in the winter, and when the outdoor temperature falls below a 55F, 45F, or whatever works best for you, the boiler fires up and steam fills the main piping. A little heat is given off by the pipes into your ship and that's okay.

Next, when each room thermostatic control calls for heat, it'll open up and feed off the filled steam mains. The combination of outdoor coldness and indoor low temperature will give you efficient heat. When a room is satisfied, it stops feeding off of the piping and the boiler.

The boiler itself has a brain and it senses when it needs (or not) to refill the steam mains with fresh steam. That's what the boiler pressuretrol does. Two boilers can work in a cooperative team when each is set (this is one method) to fire up on each its own pressure level, thereby giving a very efficient stepwise operation.

When the sun comes out and it starts getting hot outside, the outdoor thermostat goes above the (45F) and everything shuts off before you overheat any part of the ship. Extremely efficient heat.

The next big step in improvement is to tie in a timer in series with this outdoor thermostat. Now you can tell the system when you even want any heat. Set the timer to follow museum opening times and you'll be giving yourself the setback feature that gives you destroyer efficiency.

What happens without the thermostat?

I don't know that energy efficiency is one of your concerns, but not having heat appear on time or, likewise, suffering overheating discomfort are both situations you'll probably get into without efficient automatic control.

Of course, you can do all this with a bit of duct tape and just dangling the thermostat out a porthole... but the Tekmar and Heattimer and others are combined thermostat-timers that come in one neat box to which you attach outdoor (and other) sensors.

Ready to sail?

adayton_2

Thermostat out the Port

is an excellent idea Christian :-)...lol...
Assuming ALL heat distribution (zones) areas are individually controlled with their own independent thermostats then your solution "" but the Tekmar and Heattimer and others are combined thermostat-timers that come in one neat box to which you attach outdoor (and other) sensors. "" is perfect, Put a
tekmar/Heattimer on the main steam boiler. After installing this control solution I repeat the need to examine and adjust as required the venting.

PS: CJN, This solution would solve the -0- PSI "problem"..

PPS: CJN, properly vented you should NOT need more that 2 PSI unless there are very SMALL diameter and LONG piping considerations in the equation of which I am not aware.

Alfred

Christian Egli_2

Big Mamie?

I have visited the USS Alabama - did not notice thermostat dangling out the side like an extra anchor... Maybe there is something more to this...

Before you buy any brand control box, make sure you discuss it with their application engineer, so that they know you're talking about a battleship not just any ordinary home, their systems may have inappropriate features for you.

The people installing the extra boiler should have a good idea about how to stage their boiler relative to the others. These people can also very easily install a simple remote outdoor sensor for you.

The pressure you should run at is most likely governed by whatever lift height some of your unit heaters might need to reach an overhead condensate return (something to measure with a tape meter). Ships don't necessarily have straightforward down-sloping return lines like a home would. Count on rough seas rocking to disturb otherwise nicely planned pitch.

It would be a real treat to visit the behind the scene piping. Steam traps... air vents... and crossover traps galore, all together on the same system.

By the way, there was once a USS Dayton but since it didn't fly like an airplane it was turned into new steel. Plus, Dayton does not exactly have any deep harbor. A bad ending to a good story indeed.