circut setters circut setters HVACTec (Mechanical) (OP) 14 Feb 11 11:39 Looking for information on setting up Taco circut setters in Hot water systems . Thanks Mike RE: circut setters 2 MintJulep (Mechanical) 14 Feb 11 13:22 And you found the vast amount of detailed information on the Taco web site not useful? RE: circut setters MechEngNCPE (Mechanical) 15 Feb 11 12:50 Circuit setters generally are installed at the end of a heating hot water loop to allow there to be continuous flow through the piping system. It is a minimum flow device, they are generally not needed if your system involves 3-way valves. I typically design reheat coil heating hot water loops with 2 way valves, and install a circuit setter at the end of the loop, and set it for ten percent flow. RE: circut setters KLPE2B (Mechanical) 22 Feb 11 22:57 NCPE, you couldn't be any more incorrect in your statement. Circuit setters are used to balance hydronic systems, and 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, which involves a significant cost increase. Contact your local testing and balancing firm for details on the importance of balancing valves(circuit setters). RE: circut setters willard3 (Mechanical) 23 Feb 11 08:55 Circuit setters are inexpensive and you will need a shut-off valve anyway. They are required for balancing. RE: circut setters cdxx139 (Mechanical) 23 Feb 11 09:08 But if you have the option, go with the pressure independant control valve. This eliminates the need for the circuit setter, and you dont have to rely on the balancer for a balanced system. (I am not sure what the upcharge is, but by not having to rely on the balancer, I think it would be worth it) knowledge is power RE: circut setters mauricestoker (Mechanical) 23 Feb 11 10:20 I think it may depend on your pumping. If you have variable primary pumping, then I would suggest going to the PICV and losing the balance valve. If its a small system, say under 5 HP pumping then variable pumping may not offset cost. 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 MechEngNCPE (Mechanical) 23 Feb 11 14:58 KLPE, "at every terminal in the system? Different systems call for different components, first off. Chilled water primary loops for example, can be balanced with the triple duty valve after the pump discharge. 2way valve hot water recirculation piping typically needs a circuit setter at each end of the loop. Heating hot water piping could be balanced with any flow control device, VFD on the pump, bypass valve, flow control valve, etc. I don't know exacty what you mean when you say "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 btrueblood (Mechanical) 23 Feb 11 16:49 "Chilled water primary loops for example, can be balanced with the triple duty valve after the pump discharge"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 mauricestoker (Mechanical) 24 Feb 11 08:18 That would seem to be pretty much the idea behind going to variable primary pumping. I'm in the middle of converting a constant primary/constant secondary into a variable primary. The LCCA has it as the best cost over 25 years, lower first cost than variable primary/secondary, and it means geting rid of a buttload (an engineering estimation term) of ABCV's and 3-ways. RE: circut setters MechEngNCPE (Mechanical) 24 Feb 11 10:17 Variable primary AND variable secondary would seem the way to go, especially if you have large swings in demand which you normally do. Put a VFD on the chiller compressor and cooling tower fan as well and now your talkin energy savings. RE: circut setters ChrisConley (Mechanical) 24 Feb 11 10:19 Quote: Chilled water primary loops for example, can be balanced with the triple duty valve after the pump dischargeTotally unrelated to the discussion on circuit setters, other than triple duty valves are a balancing valves.Quote:Circuit setters generally are installed at the end of a heating hot water loop to allow there to be continuous flow through the piping systemThis 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 MechEngNCPE (Mechanical) 24 Feb 11 12:32 Ok Cris, so like KLPE noted, they are REQUIRED AT EVERY TERMINAL IN THE SYSTEM???? What about at a 3-way valve heating coil? And he didn't say what kind of system either... RE: circut setters ChrisConley (Mechanical) 24 Feb 11 12:53 You need 2 balancing valves on a 3-way valve, one on the return and one in the bypass.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 cdxx139 (Mechanical) 24 Feb 11 13:12 "Circuit setters generally are installed at the end of a heating hot water loop to allow there to be continuous flow through the piping system"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 btrueblood (Mechanical) 24 Feb 11 13:13 Bigger issue - circuit setters don't balance systems that are not at full rated flow, i.e. at part load. RE: circut setters MechEngNCPE (Mechanical) 24 Feb 11 14:21 Cris, you are correct, one on the bypass and one on the return. I don't think I was being clear. RE: circut setters mauricestoker (Mechanical) 24 Feb 11 16:05 I thought that the balance valves would satisfy part load conditions by pumping full volume whether needed or not-where the energy savings are. Where I've usually seen them is for maximum flow independent of pressure on multiple loops off the same pump.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 btrueblood (Mechanical) 24 Feb 11 17:40 "I thought that the balance valves would satisfy part load conditions by pumping full volume whether needed or not-where the energy savings are."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 mauricestoker (Mechanical) 28 Feb 11 08:32 I think you've got the point, but in reverse. The offset for not having to run the pump is the payoff goal of the PICV's. If you can wait 25 years, I'll tell you how it came out as compared to the estimated life cycle cost analysis. First year data will be available about 1 year from now. RE: circut setters btrueblood (Mechanical) 28 Feb 11 13:02 Ok, reread your statement, maurice, I think we are on the same wavelength. Good luck! RE: circut setters Ziggypump (Mechanical) 9 Mar 11 11:15 I'll stick up for NCPE here; He is correct that circuit setters do not need to be installed at every terminal (read coil), you also can use venturi style balancing valves. They're a little more expensive, but can be separated from the circuit setter title.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.