deadprogrammer’s cafe has a good article on steam and water heat … and a tip on how to adjust the temperature … “Deadprogrammer Visits The Radiator Planet” … using a “regulated thermostatic valve” with pics … and help from Gary the cat …

The kit usually consists of three parts: a temperature control device, an adaptor and a Hoffman-type valve. This will run you about $100 altogether. I have one on two radiators, and let me tell you, these are worth every penny.