There are not many books about biomedical engineering on the market. The few are theoretical oriented and concentrate on the design but not much on the usage and their problems in daily routine. Non of the books gives hints for repair or maintenance.
The books are written for engineers who need background information of the equipment design. For all books basic knowledge in medicine and electronics required. In general all the books are very expensive (see the Amazon links).
For an overview about principles and functions the internet is an excellent alternative - and it is for free (see Links and of course wikipedia-medical equipment).
In addition to this you will find some books and documents as pdf-files in the Biomed Books section.
Beside the biomed books often information and explinations of electrical problems are needed. It is wise also to have a book about electronics and A/C in the workshop.
Here some good books I work with:

Biomedical Instrumentation: Technology and Applications

by R.S. Khandpur
924 pages

Best book I know, practical oriented and comprehensive
A voluminous and heavy book with tons of informations. It starts with medical basics and ends with the description of defibrillators and x-ray machines. It is not too theoretical and always related to the practical use.
For me the best biomedical book. One of the most comprehensive books and not too theoretical.

Clinical Engineering Handbook

by Joseph Dyro
674 pages

Good book for hospital organisation and practical workshop management
A book for people who want to organize and run a biomedical workshop. Half of the book is about management, financial backgrounds, organizing service, experiences in other counties and other considerations around how to manage a biomedical service. The other half introduces the medical equipment. The introduction is not so detailed as in Biomedical Instrumentation but surprisingly very practical oriented. It is obvious that the author has many years of practical experience.
Again, it is not a technical book, but a very good addition to 'Biomedical Instrumentation'

Biomedical Device Technology

by Anthony Y.K. Chan
582 pages

A book for engineers. Too much theory stuff.
The best of the book is that it covers all biomedical equipment. But unfortunately it is very theoretical. The articles are peppered with countless complicated mathematical and chemical formulas. The practical usage comes off badly. A technician who needs practical explanations will be overstrained.

Biomedical Engineering Technology

Laurence J. Street
344 pages

Maybe interesting for absolut beginners
This book is a good example for how people make money getting all the information from the Internet and sell it as a book. Meaningless images of patients, body cells and other crap. Photos and schematics of equipment functions are not shown. The equipment explanations are poor and shallow. You are better served with wikipedia.

Essentials of Anaesthetic Equipment

Baha Al-Shaikh, Simon Stacey
288 pages

Made for novice anaesthetists but also highly recommended for hospital technicians with the focus on anaethesia equipment and their usage.
Excellent book, easy to read and nicely illustrated. Topics: Medical gas supply, anaesthesia machine, ventilators, monitoring, infusion pumps and more.
Go for the 4th edition. It is completely updated with new photos and diagrams.

Essentials of Anatomy and Physiology

by Valerie C. Scanlon and Tina Sanders
603 pages

Good structured and illustrated. Not overloaded
For everybody who likes to know what is going on in a human body in order to understand the functions and usages of the biomedical equipment. Of course it is more detailed than a biomedical technician need to know. But anyway a medical book like this should not be missing in a workshop.

Wiring a House

by Rex Cauldwell
248 pages

Interesting to read, excellent photos and lots of information for daily work
All about electrical installation. You think you don't need such a book? You will be impressed how interesting the topic is and how much you can learn. The book gives a lot of practical information and hints to improve your work. For example the chapter about Grounding everyone should read...

Home Wiring

by Black & Decker
336 pages

For beginners. Very detailed, maybe too detailed
Similar to the above mentioned. Good to read, nice photos and the same content. But for me it is too American ;-) Installation in this books only shows installation under wood construction and twenty colored photos of wall sockets and ten photos about how to dig a hole I don't need...

Refrigeration & Air Conditioning Technology

by Whiteman, Johnson and Tomczyk
1325 pages

Heavy-weighted title, heavy-weighted book, expensive but worse every shilingi. Simply the Best!
What a surprise! Boring title but how amazing to work with. A book simply about everything of cooling but also about electrical installation, repairing motors, piping, etc. Excellent explanations, photos and diagrams. For beginners as well for experts who think they know already everything. The best technical book I have ever seen. A must for every workshop. If you want to buy a reference book for your workshop – buy this!

Air Conditioning & Refrigeration Toolbox Manual

by Tenenbaum
396 pages

Small, cheap and good
For those who can not afford the heavy Refrigeration & Air Conditioning Technology. This is a nice alternative. Of course no so comprehensive but very helpful for your daily repairs. All parts and technologies are explained on examples from practice. A small pocket book which fits in every tool box.