What type of climate are you operating in? I'm in Canada, thus putting any equipment outdoors is a big no-no, unless you want to fill it w/ antifreeze.
Assuming you're in a more temperate climate, I imagine the biggest issues you'll run into are weather-resistance. The expansion tank isn't as...
"how common and/or advisable is it to run a boiler without a primary pump? I have come across a set-up where the 500kw boiler (700L internal water capacity) runs with zone circulators off a common header. is this a good idea?"
There's no easy answer to this, and the best answer is: it...
It depends on the climate, it depends on the size of the room, it depends on their definition of "warm", and it depends on what's going on in that auto shop. A large lighting and motor load could be causing the heat problem.
There also may be a large make-up air load if exhaust fans are...
It absolutely depends on how the building heating water is plumbed. Many older schools in my area are single pipe hot water systems w/ monoflow tees, and manual valves for "control". Real load control is based on a single thermostat controlling the boiler load. We're doing a lot of boiler...
