^ Ah, much better!
Since I haven't had a failed part yet... I don't know how I would prioritize the spares list other than by what I've read over the last two plus years on other brand mod-con boilers. It seems sensors fail more than other parts... and the good news is that in many cases they are under $10 each. I've even ordered two of some common sensors because they are so inexpensive.
Regarding the control and display boards... the problem in keeping spares of them is that firmware gets updated as program flaws are discovered and corrected. If you order a spare control board today and don't use it for 3 years... you may miss out on a lot of improvements that have been made since you purchased it. That being said, the control board is extremely important, if it fails you're dead in the water so it's important to have a spare.
Anyway, below is my current spares list for the UFT-80W. I believe my first order was about $150, the expensive parts like the control board, display board, inducer fan and gas valve I ordered later on as funds permitted.
http://www.shophtp.com/ecommerce/
My Spares On Hand....
7855P-068 $19 Ignition Rod
7855P-252 $6 GASKET, IGNITER
7855P-031 $7 Flame Sensor (2)
7855P-262 $17 Air Pressure Switch
7855P-092 $24 Exhaust Temperature Sensor
7855P-030 $15 CH Supply Temperature Sensor
7855P-097 $11 CH Return Sensor
7855P-029 $9 Water Level Detection Sensor
7855P-066 $7 Burner Overheat Sensor (2)
7855P-249 $2 O-RING, BURNER PLATE (2)
7850P-210 $8 EXHAUST & INTAKE GASKET
7855P-368 $8 Air Damper
7855P-369 $7 Air Damper Guide
7855P-425 $11 Fan Outlet Gasket
7855P-370 $8 Burner Inlet Channel Gasket
7855P-007 $47 Ignition Transformer
7855P-308 $238 Control Board (no gas sensor on board)(firmware rev 0012)
7855P-344 $91 Display Panel
7855P-025 $158 Blower Motor (inducer fan)
7855P-381 $149 GAS VALVE ASSY