Metal Minutes - SECO/WARWICK Heat Treat Newsletter
HEAT PROCESSING NEWS

Atmosphere  Maintenance Tips

Troubleshooting Endogas® Endothermic Generators

Although atmosphere generators are relatively simple and straightforward, they do require maintenance and some adjustments.

#1 Question from our customers:  How do you check the catalyst bed?

The easiest way is to make a slight change in the air/gas ratio and observe the corresponding change in the dewpoint of the output gas.

It should be noted that an increase of 17 cu ft. of air raises the dewpoint in a 1000 cfh generator by as much as 30°F if the catalyst is reactive and free of soot. With this in mind, one can do the following test: With the generator running offline, note the current dewpoint.  Then increase the natural gas flow 5 cfh and observe the change in dewpoint. Depending on the size of the generator, the dewpoint should drop 10°F or so. After it has stabilized, increase the natural gas flow another 5 cfh and observe the change in dewpoint.  Another drop of 10°F or so in the dewpoint temperature should be observed. Decreasing the natural gas flow 10 cfh should now return the dewpoint to where we started at the beginning of the test. In about 15 minutes one can determine whether the catalyst is reactive or not.

If the generator has not responded or responded sluggishly during the test, perform a burnout to clean the soot from the catalyst and perform the test again. If the response is the same, the catalyst should be replaced.

The following table lists more troubleshooting tips:

Symptoms Causes Solutions
Low Flow Soot building up in piping to furnace Clean pipes, particularly the elbows
Firecheck screen is dirty Clean or replace screen
Air filter is dirty Clean or replace air filter
Excessive soot buildup in retort Use burnout procedure to remove excessive soot.  If extreme sooting, replace catalyst
Pump motor drive belts slipping Tighten belts
Pump by-pass regulator allowing too much flow around pump Adjust regulator to limit flow by-pass.  Make sure pump motor amps are not excessive.
Flowmeters not reading correctly Inspect and clean flowmeters.  Verify that the float serial number matches the flowmeter body.  Verify float weights are not missing.
High Dewpoint Air/Gas ratio too high Reduce air/gas ratio to lower dewpoint
Excessive soot buildup in retort Use burnout procedure to remove excessive soot in the retort
Breeched retort Replace retort
Low Dewpoint Air/Gas ratio too low Increase air/gas ratio to raise dewpoint
Methane carryover in process gas Use burnout procedure to remove excessive soot.  If extreme sooting, replace catalyst.
Mixture pump won't run Holdback temperature not achieved Allow generator to reach minimum temperature for proper operation
Pump motor starter tripped Reset motor starter and monitor pump amp draw
Firecheck switch tripped Reset firecheck
High/low gas pressure switches of mixture pressure not made If pressure is correct at switch locations, adjust or replace switch
Excessive sooting Low temperature in retort Verify control thermocouple and instrument are working properly
Air/gas ratio too low Raise air/gas ratio slightly
Quality of supply gas suspect Have supply gas checked for additives
Catalyst depleted Replace catalyst
Generator will not reach operating temperature (gas-fired) Dirty combustion air filter Clean/replace combustion air filter
Burner air/gas settings not correct Adjust air/gas settings per combustion drawing
Control thermocouple failure Replace control thermocouple
Generator will not reach operating temperature (electrically heated) SCR/contactor not working properly Adjust/replace SCR/contactor
Power not on or fuses blown Turn on power, replace fuses
Heating element(s) failed Replace heating elements

For more information on Endogas generators along with sizes and applications visit

The latest design, materials and equipment specifications should be obtained from the company before any reliance is placed on the enclosed since changes may occur due to product improvement.

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Phone (814)332-8400 - Fax (814)724-1407
info@secowarwick.com

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