Blue patch I have a blue patch that shows up on the left side of my screen. The shape changes over time but it's always on the left side.

You didn't state how many hours are on the unit, but I'm guessing close to 3,000 hours, that is when most brands have LCD panel failures, due to the heat over time the coating on the lcd panels burns off, the panels start to burn up, and it gets worse with time, and you notice it more when you put a fresh bright lamp in. if it is low hours then you could have a bad lamp, that casts a bad tint, but it sounds like fried LcD panels, a sure way to tell, is put up a white back-ground screen and see if you see discolored "BLOB" in the center of the screen.
keeping the filters clean, and the projector cool is the best way to prevent this.

Its an obstruction on reflectors beyond lamp.remove lamp,clean it anyway(dry cloth)get hair dryer ,blow into casing to remove residue,re fit lamp.not the the best remedy but the other way requires disassemble and voids warranty but this disperses build up of dust

I had the same problem with my Hitachi PJTX100. I discovered that there was considerable dust build-up inside the unit, causing insufficient venting of heat which then damaged the color prism/filter. It was close enough in time to the warranty for Hitachi to cover parts replacement (approximately $1,600). Since the repair, I regularly vacuum not only the outer cover but also the inner air filter that easily snaps on and off.

Requesting projector status (Get command)
(1) Send the request code Header + Command data (‘02H’+‘00H’+ type (2 bytes)+
‘00H’+‘00H’) from the computer to the projector.
(2) The projector returns the response code ‘1DH’+ data (2 bytes) to the computer.
Changing the projector settings (Set command)
(1) Send the setting code Header + Command data (‘01H’+‘00H’+ type (2 bytes) +
setting code (2 bytes)) from the computer to the projector.
(2) The projector changes the setting based on the above setting code.
(3) The projector returns the response code ‘06H’ to the computer.
Using the projector default settings (Reset Command)
(1) The computer sends the default setting code Header + Command data (‘06H’+
‘00H’+ type (2 bytes) +‘00H’+‘00H’) to the projector.
(2) The projector changes the specified setting to the default value.
(3) The projector returns the response code ‘06H’ to the computer.
Increasing the projector setting value (Increment command)
(1) The computer sends the increment code Header + Command data (‘04H’+
‘00H’+ type (2 bytes) +‘00H’+‘00H’) to the projector.
(2) The projector in creases the setting value on the above setting code.
(3) The projector returns the response code ‘06H’ to the computer.
Decreasing the projector setting value (Decrement command)
(1) The computer sends the decrement code Header + Command data (‘05H’+
‘00H’+ type (2 bytes) +‘00H’ + ‘00H’) to the projector.
(2) The projector decreases the setting value on the above setting code.
(3) The projector returns the response code ‘06H’ to the computer.
When the projector cannot understand the received command
When the projector cannot understand the received command, the error code ‘15H’
is sent back to the computer.
Sometimes the projector cannot properly receive the command. In such a
case, the command is not executed and the error code ‘15H’ is sent back to the
computer. If this error code is returned, send the same command again.
When the projector cannot execute the received command.
When the projector cannot execute the received command, the error code ‘1cH’
+ ‘xxxxH’ is sent back to the computer. When the data length is greater than
indicated by the data length code, the projector ignore the excess data code.
Conversely when the data length is shorter than indicated by the data length
code, an error code will be returned to the computer.