The school in Bridgend had to temporarily shut doors after several of its pupils fell ill with a sickness bug.
On Friday morning parents of children at Brynmenyn Primary were informed that classes would be cancelled so that the school could undergo a thorough cleaning.
A spokesman from Bridgend county borough council said: “As a significant number of pupils at Brynmenyn Primary were absent through illness on Friday and the school boiler developed a fault, the head and chair of governors took the decision to close the school to help prevent further spread of the illness, enable the boiler to be repaired and facilitate a ‘deep clean’ of the school and its facilities.”
It has since reopened to pupils.
The illness has been attributed to the common, but unpleasant, stomach bug Norovirus.
A Public Health Wales spokeswoman said: “Public Health Wales has been working with colleagues in the environmental health department at Bridgend County Borough Council to manage an episode of a vomiting illness affecting children at a primary school in the area.
“We suspect this illness is due to Norovirus.
“Norovirus is highly infectious and a common cause of diarrhoea and vomiting.
“The illness is generally mild and most people usually recover within two to three days.”
Norovirus is often called the ‘winter vomiting bug’ since it’s most common in winter, but it can strike at any time of year.
According to the NHS, symptoms usually include suddenly feeling sick, projectile vomiting and watery diarrhoea, however people may also experience a slight fever, headaches, painful stomach cramps and aching limbs.
The bug hit the headlines in February this year after outbreaks at restaurant chains Wahaca and Toby Carvery.
Indeed, recent data from Public Health England revealed cases of Norovirus were nine per cent higher than average compared to the same period over the last five years.
The spokeswoman from Public Health Wales added: “Hand washing is one of the most important ways to prevent the spread of Norovirus.
“All members of a household with any case of vomiting or diarrhoea should wash their hands with liquid soap and warm water before preparing or eating food, after contact with infected people and after using the toilet.
“Towels and flannels should not be shared.
“People who are unwell with diarrhoea or vomiting should not attend work or school for 48 hours after their last symptoms to avoid spreading infection to others.”