Also, if you have steam flow meters installed they will generally not be accurate when running at a drastically lower pressure than intended.
Reed Sprung
Sprung Services
http://www.sprungservices.com
I do consulting and training in this area. First of all, your boilers are in no danger of being "exposed" to the deadly vacuum of your return system ;-) There is a reason you have a bypass for the PRV. There is absolutely no need to be concerned about this. The PRV protects the low-pressure...
