Derbyshire Fire and Rescue Service tweeted on Sunday afternoon to say it had just rescued the dog and that she was being given oxygen to bring her around.
Now a rescue service spokeswoman has revealed that the pet "suffered no lasting effects of the incident".
The spokeswoman said the dog got her head stuck in the opening of a 100-year-old double steel skin boiler. She said: "The dog had been fully sedated by the vets on scene and lubricant was used to free the dog.
"She just had to be eased out gradually. We didn't have to cut her out. She was then given oxygen to bring her round."
The dog's family found her stuck at about 1.40pm and she was freed four hours later.
(derbytelegraph.co.uk - May 2, 2017)