Access For Cleaning "A" Evaporator Coils
 

I have a Ruud central system. Gas heater. Closet installation with air intake below. The A coils are above the unit just below the attic. The A coil compartment was sealed with some type of sealer over tape. I removed some sealer and found a removable opening from which I can see the A coils but, I cannot access the underside of the coils which I am sure need cleaning. I also see a side cover but there is no room to work from there. It sure seems that major disassembly is needed meaning removing the firebox.
Any hints ?

Hello CliffW:
Many of the larger suppliers of HVAC have an aresol can of chemical that can clean one side of an 'A' coil per can. I think it is called Blaster, Blast Away, or something like that. It can be found at places like Grainger, Johnstone or United Refrigeration.
You will need to place absorbent material on something sturdy under the 'A' coil to catch the crud that will be blown out.
Glenn

Thanks Glenn.
My problem is that I can not access the undersides of the A coil. I would hate to back blow the dirt on top of the burner and definitely do not want to back flush.
Any HVAC sites any are familiar with which might be helpful ?

Do you by chance have a picture of your setup? Is this a furnace with a separate coil or is this a Air handler/heatpump? And you say it is a upflow setup? (return on bottom)