Balancing manifold with ECM pump

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MillAlien

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We're expanding a 20 year old single-zone system with a three-zone system (powered by a Navien comb-boiler). The legacy single zone consists of four in-floor circuits fed by a four-port Rehau balancing manifold. The expanded system will drive that legacy loop with a single Taco VT2218 ECM circulator to replace the Taco 007-F5 circulator. I was not planning on replacing the Rehau manifold, but as I contemplated this ... the manifold range is 0-2 gpm which matches the heat load of ~ 20,000 BTU. My question is whether limiting the flow rate to 2 gpm defeat the strength of the ECM circulator (which if I'm understanding its curve correctly, manages flow rate in a way that the old 007 doesn't)? Is it worthwhile increasing the max floor of the balancing manifold?
 

Fitter30

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Normal temp drops are usually 20° per zone design. With a probe type electronic since i don't like ir for pipe temps. Since the system must heat ok a baseline of td's would be a good baseline. Pump setup delta t that what i start with. Piping the navian primary/ secondary piping? Air removal a micro bubbler there are several brands Spirovent is just one. Are you happy with your pump now? If you are .67 to .71 amps between pumps will never have a pay back. They have a 007 e pump.
 
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John Gayewski

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We're expanding a 20 year old single-zone system with a three-zone system (powered by a Navien comb-boiler). The legacy single zone consists of four in-floor circuits fed by a four-port Rehau balancing manifold. The expanded system will drive that legacy loop with a single Taco VT2218 ECM circulator to replace the Taco 007-F5 circulator. I was not planning on replacing the Rehau manifold, but as I contemplated this ... the manifold range is 0-2 gpm which matches the heat load of ~ 20,000 BTU. My question is whether limiting the flow rate to 2 gpm defeat the strength of the ECM circulator (which if I'm understanding its curve correctly, manages flow rate in a way that the old 007 doesn't)? Is it worthwhile increasing the max floor of the balancing manifold?
I guess I'm not really sure what your asking. Is it worth what?
 

MillAlien

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I guess I'm not really sure what your asking. Is it worth what?
Well, I guess that’s THE question. My understanding is that the VT2218 will vary the flow rate to maintain the temp delta. The older 007 will not. The current manifold max rate of 2 gpm and my thought was that it’s capping flow rate and will defeat the VT2218, making it not worthwhile for temp delta management unless the manifold is replaced. My rule of thumb based 1 gpm per 10,000 BTU and 20,000 BTU heat load says that 2 gpm should be adequate either way.
 

John Gayewski

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A delta t pump adjust itself on temp and doesn't necessarily perform well with loops that are different lengths. A delta p pump manages the flow based on resistance and can be used with loops of different lengths.

I would leave the manifold.
 

Fitter30

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Are u happy with three zones heating guess there are no zone valves. Whats the total flow through manifold? Are u going to pipe the Navian primary secondary loops.What model unit? Look at this grundfos pump

UPSe 15-58FR High Efficiency ECM Wet Rotor Circulator Pump with Rotated Flange and Universal Programming​

 

MillAlien

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NCB-240/130H. We haven’t installed it yet, so too soon to tell about the happiness. The one legacy loop is using a Rehau balancing manifold with a 2 gpm max. We’re committed to the Taco’s at this point.
 
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