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Posted by HeatPro on November 30, 2005 at 11:34:45:
In Reply to: Re: To HeatPro and Joe Brix posted by Dave on November 30, 2005 at 11:12:28:
Actually, the entire piping mess you now have was completely unnecessary as I had said last year. The boiler pumping into and from the buffer tank with the zones coming off and returning to a buffer tank manifold would be the same and less complicated, serving both my and Joe's suggestion to have the boiler off a primary-secondary and the heating circuits off another primary secondary with the buffer tank between. If you want to eliminate much of the piping mess, you can do that. The boiler then would not pump until the buffer tank called for it which would solve the problem of the boiler being heated by the tank and gain some efficiency. That is shown in my free course drawings here:
http://64.226.150.132/hydronic/zon/bufferz.htm
I suggested that be done in January and still do; but there has been continual growth to understand the reason, so was resisted to save the plumber some time. It would have saved a lot of the 'yeah-but-here's-another-idea' posting; but would have short-circuited the learning curve. As I had suggested, you only need two 0010 circulators, one from the boiler to the buffer, and one from the buffer on the supply stub to the zones with zone valves. You then have 5 extra circulators, extra pipe, and 4 relays to put in storage for some use in the future or sell on eBay.
Yes, the bypass is unnecessary when you repipe. The buffer or the primary loop to the buffer tank is a bypass. The problem isn't solved by using 'magic' design solutions that are redundant. The bypass is a problem, not a solution - and never was, as John Siegenthaler's zero-balance design is a bypass. His design is just missing a buffer tank because the design concentrates on the problem of misbalanced piping, not mass/water relationship of a simply-controlled boiler.