TechWhirl (TECHWR-L) is a resource for technical writing and technical communications professionals of all experience levels and in all industries to share their experiences and acquire information.
For two decades, technical communicators have turned to TechWhirl to ask and answer questions about the always-changing world of technical communications, such as tools, skills, career paths, methodologies, and emerging industries. The TechWhirl Archives and magazine, created for, by and about technical writers, offer a wealth of knowledge to everyone with an interest in any aspect of technical communications.
If it's work from another employee in your company and the manual was
written under your company's copyright then it is perfectly fine to copy
word for word without noting the source in another manual under the same
company's copyright. Any employee writing documentation for a company,
whether the documentation is internal or external, is acting as an agent
for the company.
Basically, in this situation it's OK because technically you are quoting
yourself.