Convective space heater.

Defeating Overheating 

When you run the convective space heater, NSN 4520-01-431-8927, in moderate climates (like the southern U.S., for example), you're liable to overheat your tent. Once the temperature inside exceeds 90[degrees]F, the in-tent controller system fault light shows a code 10, TENT OVER TEMPERATURE. At that point, the heater will either shut off immediately or shut off as soon as the battery recharges.

After the tent cools, the heater cycles back on and eventually overheats the tent again. The heater continues cycling on and off until the outdoor temperature drops. This on/off cycling causes carbon to build up in the burner and around the glow plug. Too much carbon around the glow plug increases the chance that the plug will overheat and burn out.

So, if your heater's been cycling a lot, the first thing you'll need to do is give the burner a thorough cleaning.

Cleaning

Whether you use JP-8 or diesel in your heater, sooner or later you may have to clean the burner assembly. That's why you need to get the new Simplified Burner Cleaning service bulletin (Instruction Sheet PN 5-13-5647). It's available online at http://www.huntermfgco.com/military/bulletins.htm

Once you reach the website, click on SHC, Simplified Burner Cleaning to download the bulletin. If you'd prefer a hard copy, phone [phone], Ext 222, or DSN 256-5592.

Used along with the heater's technical manual, TM 10-4520-262-12&P, the bulletin offers a simple way to clean and inspect the burner in the field. This information will be included in the next change to the TM.

Besides needing the TM to clean the burner, you'll also need the wire brush, NSN 7920-00-291-5815, found in the general mechanic's tool kit, or a multi-tool, NSN 5110-01-394-6252.

AUDIBLE DIAGNOSTIC CODES

1. LOW VOLTAGE 

2. COMBUSTION BLOWER

3. LOSS OF FLAME

4. BURNER MAINTENANCE

5. GLOW PLUG

6. TEG OVER TEMPERATURE

7. OVER VOLTAGE

8. TIP-OVER

9. FIN TEMP SENSOR

10. TENT OVER TEMPERATURE

1. Open the tent door and cool the inside.

2. If the cycling continues after cooling off the inside, disconnect the air supply duct from the tent's air duct opening. Keep the air supply duct attached to the heater. That'll help keep rain and snow from getting inside the heater. Allow the heater to draw the cooler outside air until the cycling stops. Then reattach the air supply duct to the air duct opening.

Burner Cleaning Made Simple

The convective space heater, NSN 4520-01-431-8927, produces forced hot air to keep your tent or shelter cozy. You'll stay warm as long as you understand the link between the heater's fuel and a clean burner assembly.

Facts About Fuels

JP-8 is the preferred fuel for the heater. It burns clean and extends the life of the burner assembly. That means fewer unscheduled maintenance tasks to worry with.

If you don't have JP-8, you can use diesel fuel in the heater. But you need to know a few things about diesel:

Diesel burns dirtier than JP-8. It leaves more carbon residue in the burner, especially on the wick, around the glow plug and in the burner chamber.

More carbon calls for more cleaning. If you use diesel fuel, expect to clean the burner every 250 hours (or about 10 days of continuous operation). Use JP-8 and you'll need to clean the burner only if the system fault light shows a code 4, burner maintenance.

Carbon building up around the glow plug increases the chance that the plug will overheat and burn out. So much for staying warm on a cold winter night.