The International Cessna 170 Association

I would like to understand the IPC pg 94.95

Manifold heater has never worked in 30 years.

Cable frozen

Partner said forget it dress warmly

I am in mood for everything should work.

Why are two cables shown in drawing fig. 55?

Aircraft is C170B , sn 26433 JUly 1954.

Can you help?

You have a '54 so nothing on page 94 applies to your aircraft.

Page 95, fig 55 One cable (16) opens the flat sliding door which allows heat/fresh air into the cabin. The other one (15) selects between heat and fresh air. Pretty simple system and the start of the most effective heat/fresh air system of all the 170s. If your partner doesn't think this system works he should try to use the '52 and prior system.

I still think it odd that the fresh air cable is pushed in for "on" and pulled out for "off"....... I was pulling mine trying to turn on fresh air until I figured out why it wasn't working the way I thought it should. ('53 B model)

Also.. check your mufflers!!! I recently nearly gassed myself with exhaust in the cabin heat. Mechanic found a crack in the muffler next to an old weld on a previous crack .... a new muffler solved the problem. A $500 muffler is a lot less expensive than the alternative.

Aryana wrote:

KG wrote:I still think it odd that the fresh air cable is pushed in for "on" and pulled out for "off"....... I was pulling mine trying to turn on fresh air until I figured out why it wasn't working the way I thought it should. ('53 B model)

Also.. check your mufflers!!! I recently nearly gassed myself with exhaust in the cabin heat. Mechanic found a crack in the muffler next to an old weld on a previous crack .... a new muffler solved the problem. A $500 muffler is a lot less expensive than the alternative.

Pulling the muffs and inspecting the mufflers for cracks should be part of each annual inspection.

Yes, and mine was pulled and inspected at the annual inspection but that was ten months prior. The muffler was welded three years ago after the annual inspection revealed a crack. It took almost three years but it cracked again near the weld. I don't think I'll have another one welded.

I have no complaints with my Late B-model (sn 26541) heater. I've seen -20F at altitude and was comfortable in a light jacket. The "pull for off" on the fresh air is for isolating the cockpit from the engine compartment in case of an engine fire. Mine stays pushed in except for testing at annual time.

KG wrote:I still think it odd that the fresh air cable is pushed in for "on" and pulled out for "off"....... I was pulling mine trying to turn on fresh air until I figured out why it wasn't working the way I thought it should. ('53 B model)....

Don't think of it as cabin air on/off. Think of it as cabin-air FIREWALL SHUT OFF. PULL that cabin air knob if you have an ENGINE FIRE to keep smoke out of the cabin.

Well that makes sense now that you guys have explained it. Thanks!