They're about $160 bucks.īTW, since the Janitrol heater gets its fuel supply from the left tank, make sure the overhead console fuel shutoff valve is in the green or yellow crossfeed position.

This will still be the case after you replace the older problem- causing 42D36 combustion air pressure switch with the newer 94E42 switch. The AD note on the combustion air switch and combustion tube has to be done every 24-months or 100 heater hours TIS (Time in Service), whichever occurs first. You'll probably have to have the unit checked by a qualified mechanic that is FAMILIAR with the Janitrol B2030 series Heaters as installed on the 337's and who has a copy of the service and overhaul manual (P/N 24E25-1).

Very seldom is the 39D18 spark plug a problem. Of course, you could have other problems, like the thermostat switch as the base of the pilot's rudder pedals, or if you don't have the levers in the right position and there isn't sufficient air flow through the heater, this too will cause the combustion air switch to stop the process and the heater will flame-out. After a light-off attempt and you shut things off, you should see some fuel dripping from the overflow drain tube which comes through the left lower front engine cowl. What generally happens is, you will hear the fuel pump and regulator clicking away, the blower on full high, and the heater either trying to intermittantly light-off or not at all. The old style 42D36 combustion air pressure switch is generally the culprit and will keep the heater from operating and it is primarily through shops messing with the switch through over adjustment and consequent de-coupling of the pressure sensing spring that's inside the unit which will render the switch inoperative and your heater ka-put. The applicable AD notes include 96-20-7 pertaining to the integrity of the combustion tube (a flame erosion problem) and the combustion air pressure switch, and pertaining to the JanAero Series 14D11-7.5 fuel regulator and shutoff valve.

Do you know when the last pressure decay test was run on your Janitrol? There are two AD notes on the heater that affect the 42D36 combustion air pressure switch that's mounted on the upper forward part of the heater unit, as well as the combustion tube itself and the fuel regulator shut off valve. I'm also awaiting arrival of the Janitrol B2030 Series Heater Service and Overhaul Manual from Kelly Aerospace. I don't have the manual from Cessna yet, but it's 'on order'.

Janitrol heater service manual