I'm Jason, the sales manager at Easy Radiant Works. I was referred to this thread by another customer who has our product, and was concerned as he was so happy with his heater. I am very sorry to hear about your bad experiences with your installer and our unit.
First, you should know that your unit, if purchased and installed in 2014, is still fully covered under warranty. If you are not 100% satisfied with the unit, please call me at 1-800-403-3279 and we will do what we can to make it right.
Regarding the particular issues you listed here - if this unit is functioning correctly, there is no reason why it shouldn't be able to heat your garage. The EZ Duzzit series is routinely installed to great success in garages up to 1000 sq ft, with ceilings as high as 12', even in very cold Northern markets. The mild Southern Ontario climate shouldn't be challenging the system at all.
As you mentioned that the unit was rattling, I am wondering if the baffle in the unit didn't become misaligned. This can happen as a result of rough handling during transit or installation. If this is the case, it can cause vibration and excessive noise when the unit is operating. It may be that your installer determined this and actually removed the baffle rather than correctly re-seating it - this could also explain why you have such a strong imbalance in heat output from the burner to the exhaust end. The baffle is there to keep back pressure in the system, to slow the exhaust and allow more time for heat to transmit through the tube - if it is removed there is nothing to slow the exhaust, and all of your heat could potentially be vented prior to transferring into the emitter tubes.
I urge you to contact me at 1-800-403-3279 to discuss your situation. We take customer satisfaction very seriously. Our units last in excess of 25 years. For such a long term investment, it is important that it is correctly installed, functioning well, and that you are satisfied with its performance. I will do whatever I can to make sure that you're happy with your purchase.
Sweet way to make a glue up start off terribly, have the 4" paint roller NOT WORK for spreading glue at all. . I was able to rush into the finishing cabinet and grab my glue roller and use that like a paint roller.
Definately need to grab a different roller for the back slab.