Janitrol system not heating well, please help

[whr1966]

I have a janitrol system thats about 10 or so years old. I had it serviced back in the summer and it was doing okay heating this winter until now. It runs all the time but doesn't seem to be heating. Had it set to 70 last night and it never got higher than 60. I did notice that the outside fan unit was like frosted all over?? Is this an easy fix? Something I can do myself? Parts? Cost?

I thank you in advance for your help.
Hank

 

[picasso]

your system isint very common here, try this link

http://www.hvac-for-beginners.com/furnace-troubleshooting.html