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Posted by Ron on November 17, 2005 at 10:19:17:
In Reply to: circulator vs gravity posted by Daniel on November 17, 2005 at 00:56:48:
The near boiler piping is critical in a gravity hot water system conversion to a forced gravity system. You must reduce the pipe sizing from the boiler to the existing piping and install a boiler bypass. Use about 1/2 the pipe size to the old existing pipe. Size the circulator for the system and a boiler bypass has more water bypassing the boiler then what is going through the system. The cool return water will bypass the boiler and allow the boiler to achieve an average water temperature above 140f so it stops condensing for boiler protection and get hotter water to blend with system water. This will drop system water temperature. Old gravity systems work with lower system temperatures and have larger radiators. This piping will allow for better comfort while protecting the boiler.