The market initially reacted negatively to the news, despite the company also upgrading its earnings guidance for the financial year ending March 31, 2016.
If conditions remained the same, it expected full-year net profit after tax of about $135 to $140 million. But the company's shares eventually bounced to close up 1c at $7.23.
"You do sometimes see CEOs leave and then things take a turn for the worse or taper off a bit - I'm not suggesting that's the case with Fisher & Paykel but it is always something that keeps investors a bit wary when you're getting a very good CEO who has presided over a very successful period of growth and profitability, leaving," said Craigs Investment Partners Mark Lister.
"Things are tracking well for them but this succession change will be why the market might be applying a bit of caution."
The company has opted to appoint a candidate with almost as much experience as Daniell - Gradon has been with the business for 32 years, something JB Were equity manager Rickey Ward said was a good sign that the business was nurturing its people to take over roles in the future.
"It's always been Mike that dominated the discussion because he is the leader, so I guess the question the market might ask is what style will Lewis bring that will be different to Mike's," Ward said.
"Mike was clearly very articulate and on top of everything and answered every question that needed to be answered, so it will be interesting to see whether Lewis has the same aura about him."
Ward said he was well known to the investment community.
Daniell will remain on the company's board and, although Lister said this was likely to ensure a smooth transition, Ward said it might be viewed negatively.
"People who look closely at governance sort of frown upon it a little bit when you have CEOs or MDs step up and become directors on the board because it's really hard for a new leader to take control when the previous leader is still looking over your shoulder like they have in the past," Ward said.
"But time will tell."
During his time in the business, Daniell helped drive the company's diversification from its traditional invasive ventilation market into the obstructive sleep apnoea market and then into non-invasive ventilation, oxygen therapy and surgery.
Mike Daniell
Age: 58
Born: Hastings
Education: Hastings Boys High School, Auckland University BE in Electrical Engineering
Family: Married to Glenys, with a son and a daughter
Hobbies: Tramping, photography
