She said the boiler was kept at a low level and water flooded in, damaging its parts and soaking wooden pallets used to fuel it, causing between $6000 and $10,000 in damage.
She said the rest of the school week was needed to fix the boiler and dry out the parts. Students were told they were not getting a holiday.
"The main thing for us is all learning continues . . . They are still working really hard. It's a great thing with technology they can work anytime, anywhere."
She said teachers and students already used online systems and students had been given work to complete for the week.
"They [the teachers] are expecting them to work."
She said teachers remained working at the school from Wednesday until today in staff rooms heated with heaters.
The school's boiler has already broken down this year, with the school having to close for two days in May. That fault in the boiler was not related to this week's flood damage.
"It needs to have a full safety and operational check and hopefully it will be okay on Monday."
She said the timing wasn't ideal as there were senior exams next week and she could understand parents and students' frustrations.
Mrs Gibbons said the school had been working with the Ministry of Education over its property plan but heating the school with electricity wasn't an option because it was too expensive.
"We are looking at how other schools are heated," Mrs Gibbons said.
