The Galaxy 170 CO2 incubators are around for quite a while. That said, their models are in principle quite the same over the time. Thus, you might try to learn something from the manuals to the newer models, in particular 170-201 (http://www.cultek.com/inf/otros/perfil-proveedores/perfil_rs/galaxy_s_user_manual.pdf) or try to contact Samson Scientific (http://samsonscientific.com/products/spare-parts/galaxy-standard.html) who carry spare parts for you model, thus might be in possession of a manual. Last, but no least, you may try to contact Eppendorf, who took over the RS Biotech business and thus should have the old manuals available.