Posted by Harold Kestenholz - Hydronic Network on August 26, 2001 at 08:03:04:
In Reply to: New boiler for Parkton Presbyterian Church, in NC posted by Jack Hughes on August 26, 2001 at 07:33:05:
This is the time to change the old system from steam to hot water heat. The pipes for hot water are smaller and do not have to intrude into the useful building space. The hot water system will pay for itself over the replacement of the steam and electric units. New piping will require less maintenance and the new pipe will provide fewer unpleasant surprise repairs than 100-year-old pipes.
You will have to pipe new radiation to replace the electric heaters, so this requires a new zone. Sanctuaries, fellowships, and classrooms take place at differing times. Keeping them all warm to heat one just area is expensive and steam heat is difficult to zone and more expensive to run than hot water, which can be easily zoned to allow functions to occur without having to heat the entire building.
Selecting steam boilers uses a different method than hot water. Steam radiators must be filled with steam on every cycle, so the boiler is selected by counting the equivalent square feet of radiation and allowing for heating the pipes. Hopefully, the radiation in the room is sized by doing a heat loss estimate. You can find the procedure for estimating the amount of heat required for radiators at http://www.hydronic.net
Selecting a hot water boiler is done by estimating the heat requirements of all rooms. Choose which system you will use and use the appropriate methods.