I have a new Modine HD75 Hot Dawg heater that was just mounted by my local HVAC contractorn in my workshop. It was installed at an approximate 15 deg angle from the exterior wall so that the clearance at the rear of the unit on the side closest to the wall is approximately 11". The rear clearance on the other side of the heater is over 48". Because the installation book calls for 18" clearance at the rear, I did not pass my inspection. The inspector said if I could get a letter from Modine saying this was OK that he would accept that. Do you think that I can get such a letter from Modine or should I just bite the bullet and straighten it out to get the 18" of clearance? Thanks for your help.