Double heater - one side lights the other does not.

Most likely there is a bad thermocouple on one side.

Heater will not light.

Is it a new tank? Can they hear the gas flow? Gas does not immediately flow from brand new tank.

Purge (let air out) of tank for about 10 seconds or so. Repeat process. Strongly recommended to take back to dealer for purging. Tank should be kept outdoors at all times.

When lighting heater and holding in plunger, heater does not stay lit or stays lit for 5 minutes then goes out.

Most likely a bad thermocouple (or a nut may be loose).

Not getting right  mixture of propane and air.

First check the opening, in either the venturi tube or the orifice. Blow air through the orifice, or use small wire probe making certain it is clean. Make sure nothing is in or blocking the venturi tube.

Orifice may need to be cleaned out - may be plugged. Cobwebs in the venturi tube.

Clean orifice with air gun to blow out any debris or use small wire probe. Clean venturi tube with air gun or match stick.

E-Z heater will not spark.

Electrode not connected to igniter or electrode not pushed in enough in igniter.

Check wire connection to igniter.

Heater is burning in back of screens. May also notice a loud roaring noise.

Screen could have holes in it or be worn out (uneven or buckled screen surfaces). Regulator might be set too high.

Replace new screen assembly 1040 (screws for replacement included). Use 1/8" drill bit to drill out rivets. Take care not to bend reflector. As a last resort, snap off small cap on regulator knob. With heater lid in the high position, use an Allen wrench to turn brass adjusting screw 1/4 turn counter-clockwise, which will reduce the heat slightly. Repeat as necessary.