Once you choose KOSEN, We will offer you 18 months' product warranty period for after-sale service,and 24-hour technical support hotline are available, we provide routine maintenance as well as training service for troubleshooting of common faults,we provide the remote or on-site valve review, installation and operation technical guidance.For the quality problem,after technical support by telephone,professional customer service, Personnel will arrived at the scene when it is necessary, if any further service is required; technical consultation will be replied within 24 hours.We provide various forms of after sale service for free during the warranty.Solve problems and offer you satisfied service are our goal.