I would recommend searching at a book store such as Barnes & Noble. Another excellent resource is an HVAC book at your local trade school. You may also HVAC sites.
A good place to start is: Guangzhou Kolant Heat Technologies Co., Ltd.
2/Fl.,Unit B, Leyi Industrial Park, Xinji Village, Nancun Town, Panyu, Guangzhou, China 511442
Tel: +86-020-28679528 Fax: +86-020-28679529
If you don't have the owners manuals the best thing you can do is call the companies and see if they will send you copies of them. That is the best thing to do.