Re: gravity hot water recirculating loops
Posted by hj on November 16, 2001 at 08:05:55:
In response to Re: gravity hot water recirculating loops
The two main requirements for a gravity loop are that there be a constant slope up to the far end of the loop and a constatnt slope down back to the water heater, and that there be no high points where air can accumulate. In addition, it works better if the water can retain some temperature all the way around the loop so that the maximum comvection circulation can occur. Small tubing can be difficult to install to avoid high points and it radiates temperature so that the water in it has to be forced back to the water heater instead of moving on its own. The advantage of larger return sizes, is that if the convection system does not work, possibly because the existing system was not installed properly to allow it to function, then a pump can still be added to it. That is not possible with smaller sized tubing.
: Gravity hot water recirculating loops. I have seen two applications of one-fourth inch i.d. flexible copper tubing. What is likelyhood of success if applied to a lateral run of 50 feet from first floor sink to basement water heater drain valve(vertical drop about 9 feet)? What is likelyhood of success if applied to a lateral run of 40 feet from second floor sink to basement water heater drain valve (vertical drop about 18 feet)? Would the loop be more successful if 3/8 inch tubing is used? What are the primary concerns in this loop?




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