Power cut shows up water fault

Ruapehu Bulletin, Volume 10, Issue 459, 27 October 1992, Page 1

Power cut shows up water fault

Power was cut to the Waimarino area on Thursday night after a Powerco power cable blew out. The fault caused the Makaranui Substation to cut out, which meant King Country Energy customers in the northem parts of the Waimarino were also affected. Ohakune people suffered a second time when they awoke Friday moming to find that their water supply was cut. Disruption to the supply was caused by a computer malfunction at the new water treatment plant, in tum caused by the power cut. "When the power came back on the computer started the plant again, but the power was cut a second time," said district engineer Don Sattler. He said when the system's automatic controls activated the second time a valve was damaged, causing the shutdown. The system is designed so that in the event of a plant shutdown, an automatic telephone call is made, advising staff of the fault. "Unfortunately the call was to the Taumarunui treatment plant at Ongarue, which

was switched to the council offices - but of course the machine only got the office answerphone," said Mr Sattler. Waimarino staff were not aware of the problem until advised by residents, at about 5.30am. While attempts were being made to contact the plant 's manufacturTurn to page 3

Water power

Frpm page 1 ers, the plant was bypassed so the town could be supplied "with raw water. Whcn the plant's manufacturers were contacted, they advised staff to divert the raw water through the plant's backup chlorination system. By 10am the damaged valve was discovercd and repaired, and UV treated water was again flowing. Mr Sattler said it would take a few days for the raw water, the chlorinated water and air pockets to be purged from the reticulation system, so the townspeople were advised to boil their drinking water. "In some ways it is fortunate that the problem has happened now because the plant is still within the commissioning stage, so it is up to the contractor to fix the faults," said Mr Sattler. "It won't cost the ratepayer anything to repair the plant." He said a better system of contacting staff would be worked out, so that the right people were called in the ' event of a fault.