I was recently consulted about a boiler that a friend of mine has at he and his wife's dry cleaning business.  I don't have any experience with dry cleaning equipment, but the steam side of it should be all the same.  We need some help...

     The steam plant is a 15 horsepower Fulton boiler that runs at 85 psi during production.  It is just over 1 year old and they have had to replace what the service tech called the flame rod - igniter assembly, twice.  They have offered no explaination for the premature failures.  What would cause that assembly to fail after 6 months, twice in a row?  I suspect it is going to happen again in another 6 months. 

     They also told me that they suspect the salt from the water softener or the boiler chemicals are turning white shirts yellow.  Has anyone ever heard of this happening, or know what the real problem is?  They are getting little to no support from the manufacturer of the dry cleaning equipment.

     One more issue.  When the boiler cycles off at 85 psi during production, it doesn't come back on for about 20 to 30 minutes.  Today it cycled off at 85 psi, and within 30 seconds cycled back on, cycled off at 85 psi, and did this the rest of the day.  Coincidently, it started doing this after the flame rod - igniter assembly was replaced, but I don't see a commonality between the two.  Sounds to me like something is water-logged.  Any advice is appreciated.

Submitted on their behalf by:

Jeff Gardner - Plant Engineer - Healthcare Waste Solutions, LLC   

Jeff,

Unless there is something REALLY wrong with the softener it shouldn't be causing a discoloration problem in the clothes.  The softener's purpose is actually to remove hardness (minerals, salts, etc) from the water, not add salt and stain the water yellow.

Even if the softeners were adding something they shouldn't be, the boiler acts like a still.  Unless there are other problems like carryover, salts and the like will accumulate in the boiler and will not leave with the steam. 

That being said, have you or anyone else done a hardness test on the softeners?  That would be a good place to start.  Check that and post the results if you have time.  TDS and pH tests may also be a good idea.  A very high TDS could cause carryover which could foul a process like dry cleaning.

Are they using any type of water treatment chemicals?

If the boiler is short cycling every 30 seconds it may not be surprising that the component that starts/ignites the boiler is going bad early.  It's tough to determine for sure, but I would focus on the short cycling issue and see if the igniter failure problem takes care of itself.

The operating pressuretrol should have an adjustment on it to control hunting.  This is normally called the differential adjustment.  Try increasing this (it would be the screw next to the adjustment screw for the set pressure).  If the differential is 1 and the steam setupoint is 10, then the boiler shuts off at 10 and starts back up at 9 (psig).  If the differential were set at 2 then the boiler would shut off at 10 and come back on at 8.  Obviously, in this case you would want to set the differential as high as you can without causing an unacceptably low steam pressure before the boiler restarts.  I would also adjust the set pressure as high as conditions permit so you have more room for a big differential.

If you can't adjust this so there is a reasonable time period before the boiler cycles then you may want to look at other things.

Is the burner capable of running at different firing rates or does it just shut off and turn on as needed?  If it just shuts off and turns on in response to the load, then you may need a different control system and/or burner.  Another thing that could help would be some type of accumulator or another small boiler to make the steam pressure drop slower.

-Reed