Please read this advice from Pepsi and check your machine. Could you ensure the Pepsi machine condenser grill is cleaned regularly as it will help the machine perform efficiently.   Pepsi drinks dispenser cooler unit - advice during hot weather

During hot weather, the back of house cooler unit for the Pepsi drinks dispenser works much harder to maintain a constant drink temperature. Britvic advises stores to keep the condenser grills clean and free from obstruction, in order to maintain the optimum performance of the cooler.