circut setters
circut setters
(OP)
Looking for information on setting up Taco circut setters in Hot water systems . Thanks Mike
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RE: circut setters
RE: circut setters
RE: circut setters
RE: circut setters
RE: circut setters
knowledge is power
RE: circut setters
Rebalance is a significant issue, especially when the ABCV's age. Last two I had to have cut out because they would no longer budge from their set positions. Trying to find the ABCV's can be a task by itself.
RE: circut setters
"they are required at every terminal in the system, even when there is a control valve present. The only exception to this rule is when the control valve is a pressure independent type"
You must not design chilled/heating hot water systems. Stick to plumbing buddy. Be sure to install your water hammer arrestor.
RE: circut setters
Do you mean you dump some percentage of the pump's output right at the pump head? Seems a bit wasteful, esp. in a system that's running at 20-30% of max design load. Would seem to make more sense to put PICV's at each terminal and back the system up the pump curve, lowering energy costs due to pumping. Yeah, the first cost might be high, but it pays off to the building owner in lower energy costs over time.
RE: circut setters
RE: circut setters
RE: circut setters
Totally unrelated to the discussion on circuit setters, other than triple duty valves are a balancing valves.
This is an incorrect statement, which KLPE2B noted. There is really no call for you to tell them to go 'back to plumbing'. KLPE2B's description of circuit setters was accurate and concise.
RE: circut setters
RE: circut setters
I'm assuming that in this case, terminal would be a terminal device (coil, panel, HX).
You don't NEED ONE AT EVERY DEVICE, provided you don't mind having UNBALANCED flow in your system.
RE: circut setters
I think he means this to be a Griswald valve, which will provide a minimum flow through the hot water system that would be equal to the minimum flow of the pumps on VFD's lowest speed, as to not over pressurize the system.
knowledge is power
RE: circut setters
RE: circut setters
RE: circut setters
NCPE-you only need one balance valve if you have only one device on the loop. Two of the heating loops I've been working are constant volume with Griswald's. On one, the design flow was 837 gpm for 840 gpm pumps. The valve choked flow down from 840 to 837. The other choked flow from 440 down to 437 gpm. I lost both griswald's. Valves are not always needed on the return, sometimes you luck out. Also was a chance to bypass the VFD's some meathead had put on a constant volume system.
FYI, the larger chillers are IGV's. The small unit is VFD; cooling towers are pony motor plus VFD motor. The LCCA bore it out, with electrical escalation factor being the most sensitive-depending on kw costs for 25 years, either one could be lowest cost.
RE: circut setters
Pump energy (in terms of input energy to a centrifugal pump) is best minimized by minimizing flow, not by allowing full volume flow.
Pumping at full volume returns "partially used" chilled water or hot water back to the chiller or boiler. Neither result gives best efficiency for the chller or boiler.
So how does that save energy?
RE: circut setters
RE: circut setters
RE: circut setters
How many people understand the effect of fluid dynamics? Path of least resistance? Lets say that the system has 440 cfm at 100 ft. head. What would happen to a coil that is about 50 feet (pipe length, size doesn't matter) from the pump, and needs 15 cfm to heat or cool properly (there are going to be a buttload - engineering term - of terminals in the system). Without a circuit setter (or balancing valve), a lot more than 15 cfm is going to pass through the terminal. This is why it's called balancing the system. You "balance" the flow to supply the required flow to each and every "terminal" in the system.
In essence a circuit setter is a bottle neck. It creates pressure loss to allow the proper conditions to be met in the terminal, to allow proper use of the unit.
*Lots of explanations because some people can't read between the lines, and need it spelled out for them. And buttload was used because that's just fun.