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Posted by heatpro on December 02, 2005 at 11:05:51:
In Reply to: Re: Change in my repiping/buffer tank schedule posted by Dave on December 02, 2005 at 10:05:56:
: Just to be 100% sure, we need no checkvalves beyond what we currently have? We will only have an IFC in 0010 pump and check valves just beyond each individual zone pump. Currently, there are no check valves on return piping at all.
No; the majority of circulator zoned systems have the flow check at the supply and none at the return - this system need not be different. If water is stopped at the supply side of a circuit, not much water can flow back up the return by small gravity flow; especially coming from the bottom of the tank.
: I assume my existing Potter Flowswitch would go in the outflow pipe from the boiler to the buffer tank? Its function is to shut off the furnace when there is no flow.
+++ Yes; it is best to have it shut off the burner in case of no flow.
: We have NoBurst 100 in our system in a 50/50 mixture as 2 of our air handlers are in unheated spaces. Do you recommend replacing it every 3 years or so? I believe it is very expensive and would involve a total of 50 gallons every few years.
+++ Provided you can keep the system from leaks, so that no air can get into the system, the mixture can stay in there over many decades. It is oxygen and liming from fresh water that forces the renewal when the midcture is no longer enough of the mixture.
: Our Phase III is the last zone on the supply header. Since it only has about 8 gallons of boiler water circulating around it, will we notice a significant difference in hot water recovery at the lower end of the buffer tank temp (150)? we have the DHW temp set to 130 on the Phase III.
+++ The flow rate of the Taco 007 with the Phase 3 resistance of the coil still provides enough flow of 150F water to heat the tank. It is more probably rated at 170F water for the full amount; but you still have far more than an electric heater would provide; about 80 gallons of first draw.
: The Lochinvar storage tank has a baffle in the boiler inlet to cause the water to mix better. Will that cause a significant decrease in flow in the boiler loop? I am just afraid of having a low flow situation with that boiler.
+++ No. the baffle is there to prevent cold water mixture with the hot above. There would be little sense of putting a 2-inch tap on the tank with a restriction that would prevent such flow; I'm sure the engineers became aware of that.
: Again, thank you so much for all your expertise. I finally feel it will solve all our issues.
: Have a great weekend, and I will update you when it's all redone.
: Dave
+++ Good to hear about the progress.