Visible crew/equipment: When Gage and DeSoto are at Harry Teal's house for the third time, there is an actor's white tape mark on the floor in front of the cabinets, just below where the Biophone is placed.
Continuity mistake: While Brackett is with Ken in the ER he's wearing a blue/white striped tie, and when he calls Ken's doctor the tie is tied differently, but then it's tied the original way.
Other mistake: When all the guys are asleep in the dorm, at 12:47 AM the dispatcher drops tones for Squad 51 and we hear him say, "Squad 51, person sick," yet the footage that is shown is of all the guys getting up, not just Roy and Johnny, putting on their turnouts.
Continuity mistake: When Brackett leads Mr. Teal to his wife they walk into treatment 2, which has a windowless door, but in the shot from inside the room they're actually in treatment 1, which has a window on its door.
Visible crew/equipment: When John and Roy are dispatched to the couple's house, for the second time, after they've checked the rooms upstairs and downstairs they join the couple in the living room, and the reflection of the large overhead set lighting is visible in the mirror hanging over the mantel.
Continuity mistake: When Johnny and Roy are in the water trying to rescue the the man trapped in the submerged car, they are wearing water-type shoes, not their regular uniform shoes.
Visible crew/equipment: During the rescue of the man trapped in the submerged car, when 110's Captain is handing John and Roy (who are in the water) the cave-in gear's air hose, in the shots from behind him on deck, the reflection of a crew member wearing white pants can be seen on the chrome surface beside him.
Visible crew/equipment: The first three times that Squad 51 is dispatched to 1012 Clinton Drive, before they leave the apparatus bay, we can see the reflections of set lighting in the squad's spotlights, particularly the driver's side.
Revealing mistake: During the rescue of the man trapped in the submerged car, when 110's Captain hands John and Roy (in the water) the special cave-in gear's air hose, then when he opens the O2 valve and also when he revs up the jaws, we see that The Boat's port side has a taught line tying it off at the stern in the closeups (seen from The Boat's deck) to prevent it moving, but in the long shots there is no line.
Continuity mistake: When Engine 51 rolls up to the Teal house and quickly enter, we can see the flames inside through the living room window - no shade blocks the view, but in the next shot from the living room, the shade is now pulled halfway down the window.
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.