View Full Version : steam boiler shuts down every night?
05-24-2005, 10:06 PM
Meet this dry cleaner. They use a steam boiler during normal operation. The owner shuts it down every night to save gas.
I'm used to seeing a steam boiler shut down a few times per year but not every night. My question is - is it bad for the boiler to be shut down every night?
05-24-2005, 11:58 PM
As long as it does not freeze & starts up I do not see a problem with it.I would look at an overnight shutdown like an extended off/cycle or no call for heat.
05-25-2005, 02:01 AM
Yes it is hard for it. The brick work expands and contracts which will cause it to flake and shorten its life. Tube sheets and tubes will expand and contract loosening tubes in time.
So it is a disadvantage to the boiler.
In the other coulmn. the expence of firring the boiler all night. safety of boiler firring all night with no one there or the expence of manning the boiler all night.
Which ever column is bigger is the on to go with.
05-25-2005, 09:04 AM
Also every time they shut down they go into a deep vacuum that will either waterlog the boiler by sucking in all the make-up water or suck in a bunch of air that will eat the tubes through oxygen pitting. Either way it's lots of extra stress on the boiler in addition to what Snipe mentioned.
05-25-2005, 01:42 PM
Every small dry cleaning shop I have seen does the same thing.
Dry cleaning is a low margin, volume business and they watch every penny....even at the expense of a dollar later.
The majority of boilers used in dry cleaning shops are designed for night shut down. Now do not equate this with a long life expectancy that you would from a central plant boiler. I remember my first encounter with one in a cleaner's shop, it looked ancient, when I called the factory for an oem part I found it was only 6 years old. Cleaners are also notorious for lack of maintenance.
05-26-2005, 12:16 AM
I hav alot of different process boilers I service that get shut down every night.One gets fired 1 or 2 times a week & is over twenty years old.I still don't see a problem with it.
05-26-2005, 11:13 AM
probably a colombia ct hi pressure,80 to 100psi ,,we add additional l404 pressuretroll set at 15 psi with a on off switch,to keep system hot during overnie layup
05-27-2005, 10:26 PM
I agree with MDP and Markwolf. The cleaners I service dont
do any maint. They just call when it doesnt work. Thats
always a fun call to run.
I think in a way the question may have been phrased wrong, as that is not a boiler but a steam generator.
Most if not all of the cleaners that I service us Fultons for this process, and they are pretty basic down fire double pass design.
They have to be the most dangrous piece of crap that they own, when ever you first fire one up watch just how fast that gauge goes from 0 to 125.
Then look around and see just whats connected to that steam main, and run the hell out.
I have seen garden hoses, inport gate valves rated for what would call less than 30 lbs used to control defferant peices in the plant.
I mean they are scary.
05-28-2005, 07:49 AM
Great, a lot of good replies.
I did not know that HVACR men service dry cleaners. I guess it's my lucky day.
What do you guys know about the dry cleaning process and basically how those dry clean machine works?
I know it uses a refrigeration system but I don't know what it is cooling.
05-28-2005, 09:04 AM
Basically heat evaporates the chemical out of the clothing and a refrigerated coil is used to condense the chemical and reuse it.
bjd is correct, the proper terminology is steam generator. I thought I was the only one scared of Fultons in cleaners shops. Very high recovery rate and watch out for the broom stick against that pesky relief valve thats always blowing off.
05-28-2005, 09:33 PM
There are alot of variables involved with the economics of shutting down a boiler everynight.
Older versus newer, pressure ranges involved, volumes involved, refractory types, etc, etc:
A steam generator is better suited for this than a traditional boiler.
It's very common for smaller boilers to shutdown in the daytime then fire at night, much more un-common for larger units to fire that way.
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