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Bizarre VAV problem
I agree with IMOK on the water flow, if the design was for 1.06 and you are now at 1.5 then the water flow is too great for the volume of air you are passing over the coil. Are these actually Griswold automatic flow controllers or are these the Griswold manual balance valves? If they are the...- TFurst
- Post #10
- Forum: HVAC/R engineering
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New Chiller Design
In response to the question about the Griswold flow controllers, they are actually a variable orifice balance valve. One of the problems with any hydronic system that uses two way valves and A VFD is that as the different control valves modulate in response to load changes the actual system...- TFurst
- Post #7
- Forum: HVAC/R engineering
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Bizarre VAV problem
Have you checked the reheat coil at the box is it operating at capacity? You didn't state whether it is HW reheat or electric but if it is HW then I would also check the control valve and actual water flow at the coil. It wouldn't be the first time I've seen a reheat coil get plugged up with...- TFurst
- Post #4
- Forum: HVAC/R engineering
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HHW boiler modulating burner control
Keep in mind that the high limit control on a hot water boiler is mounted on the outlet side of the boiler and if you are controlling the burner cycle and modulation from return water your setpoint needs to be offset to account for the design temperature rise through the boiler at the minimum...- TFurst
- Post #6
- Forum: HVAC/R engineering
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New Chiller Design
A VFD and two way chilled water valves is a great system, in addition to this I would recommend using Griswold or Flow Design flow controllers at each coil as they will modulate to maintain the correct flow rate regardless of where the pump is operating at on its curve and how many other coils...- TFurst
- Post #3
- Forum: HVAC/R engineering
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a bad experience descaling a brazed heat exchanger
I don't know what brand descaler you were using but if it is like most it contains hydrochloric acid. If this is the case then the cleaning solution is most likely what caused the heat exchanger to fail. For stainless steel heat exchangers never use anything other than sulfamic or phosphoric...- TFurst
- Post #3
- Forum: HVAC/R engineering
