Continuity mistake: When Kent (Bobby Sherman) is ready to leave Station 51, the guys are about to sit down to dinner and the table is full of food, plates, cups, utensils, etc, but when the tones drop for the refinery fire and everyone rushes into the apparatus bay, the table is seen behind them and it's bare. Also, the order in which the guys run out of the kitchen is completely different, depending on the angle of the shot.
Visible crew/equipment: When Roy and Johnny get to the gas station, Captain Stanley tells them to look at the owner of the station, and when the owner leans over and places the nozzle back on the pump, the outlines of the mic transmitter and wire are visible on the back of his shirt.
Continuity mistake: When Dixie has her hand caught in the coffee dispensing machine, Roy gets it free, and when she pulls her hand out all of her nails on that hand are very short in the closeup, but in following shots her nails are quite long, as usual.
Propinquity - S3-E20
Continuity mistake: When the victims are loaded onto the second ambulance with Roy, after the original ambulance was hit by the car, we can see the license plate, Z99977, as Johnny closes the back doors. Then while en route to Rampart, the ambulance's make/model changes with plate, Z99953, then the make/model changes yet again, but still has the same plate, Z99953.
Inventions - S3-E22
Continuity mistake: When Station 51 is on site at the major chemical leak, Roy and Johnny are wearing SCBA tanks that have distinctive markings/stickers, and their tanks change while they search, locate and rescue the worker.
Continuity mistake: When Johnny and Roy are in the basket with the man who was electrocuted by a power line, they are atop three more power lines. Chet and Mike cut the two outer lines and only the center line remains, but in the closeup of the basket there are still three power lines under the basket.
Continuity mistake: After Dr. Early fixes the squad's engine problem, while Roy is driving we see a two-way radio mounted at the top of the dashboard, just past the steering wheel. When the dispatcher calls on Squad 51 to respond, there's a closeup of the Motorola two-way radio/Interceptor units which are mounted under the dash (near gas pedal), and Johnny lifts this mic, but then we see that he's speaking on the mic from the top of the dash. Additionally, in those two closeups of the two-way radio, we can see the gas pedal, but Roy's foot is nowhere to be seen, even though the squad has been moving all along.
The Promise - S3-E11
Continuity mistake: When Roy and Johnny try to subdue the out-of-control patient on Rampart's ledge, after Brackett tells them that he'll go to x-ray right away, Roy's helmet is off, but in the overhead shot it's on his head, then in the next shot Roy puts it on his head.
The Promise - S3-E11
Continuity mistake: When Station 51 is dispatched to the people trapped in the house, Johnny and Roy clear away all the tumbleweeds from the front door, but in the next shot facing the door there is another huge tumbleweed in front of it.
The Promise - S3-E11
Visible crew/equipment: When Paula walks in the kitchen's back door holding the dog, in the overhead shot the actor's black tape mark is visible on the floor by her feet, which was not there when Johnny had first seen her.
Continuity mistake: When Roy and Johnny are climbing the aerial ladder to get to the boy on the ledge, in the overhead long shot we see down below that the Biophone and drug box are placed on the ground, right beside 85's captain. Then later, after the boy tries to jump, the captain instructs one of his men to go get the paramedics' Biophone and drug box, even though we saw them already placed there awhile ago.
Continuity mistake: After rescuing the young boy from the structure fire, when Roy and Johnny are stopped by a reporter with a camera crew and asked questions, the boy is standing behind Roy, then between shots the boy is standing in front of Roy.
Audio problem: When Truck 85 raises the aerial ladder so Roy can get to the boy on the ledge, the aerial apparatus operator tells Roy, "DeSoto, up the ladder," and we hear Roy respond, "Okay, Cap." There are two problems here: first, Roy's mouth movements are not in sync with what we hear, and second, Roy is not responding to 85's captain, he's responding to the aerial apparatus operator. The captain is standing on the ground behind Truck 85.
Continuity mistake: At the structure fire with the trapped young boy, when Johnny and Roy enter the building Johnny's SCBA tank is all yellow - no stickers, and Roy's tank has a white sticker and a red sticker, but in the following shots looking for the boy until they exit the building, their tanks keep on changing.
Visible crew/equipment: When Engine 51 gets dispatched to their first run on the new Ward LaFrance engine, Captain Stanley tells Johnny and Roy to get their gear to go with them. When the paramedics go to the closet to get the turnout coats, the bulging outlines of the mic transmitters and wires are visible on the sides of their shirts before putting on the turnouts. The outline of Johnny's mic transmitter is also visible when he first walks over to the new engine.
Inventions - S3-E22
Character mistake: Dr. Brackett calls Dr. Early "Jim." In the show, Dr. Early's first name is "Joe."
How Green Was My Thumb? - S3-E17
Continuity mistake: When the squad and engine roll up on scene at the winery fire, there are wood barrels at the back of the burning trailer, and in consecutive shots the short barrel at the back left corner suddenly appears out of nowhere, then disappears, and then it reappears again.
Revealing mistake: After the snakebite, when the guys carry Johnny and place him at the back of Engine 51, the chrome spotlights are shiny and reflective, but in the closeups the spotlight near Marco has been partially sprayed with a dulling spray, to prevent the camera's reflection.
Visible crew/equipment: When Roy and Johnny are in the basket with the man who was electrocuted, after they finally get the victim on the ground and surround him, the shadows of the cameraman/camera are visible mainly on Roy and Captain Stanley.
Answer: I believe you are speaking of the old man, Mr. Wilson. He's played by J. Pat O'Malley.
Bishop73
Correct, it was J. Pat O'Malley...he also played the grandfather with his grandson when their rocket exploded, and also played "Old Bill" in the episode with Ann Prentiss, where Gage saves the little girl from the burning tree house, and her mother falls in love with him.