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Is it the static pressure in the system or the differential pressure at the supply and return tap you are worried about? If you are worried about the differential pressure I would decouple heat exchanger pump from the building pump. The HEX pump will see the pressure differential caused by...

Bless your for trying. If you have a contact for sheet metal supplier or a contractor go visit them and see what is sold and installed in your area. I tried the same thing, then reality slapped me the face.

Inch and Novice have answered your question. Parallel fans should always be similar as the the one w/the most balls (that's a MT Tech technical term) will override the other one. Fans in parallel (assuming the same size), double the air flow while working against the same differential pressure...

This is a question for the blower manufacturers. In short, there are theoretical calcs, but they are just that.

I just glanced thru this. You have a tad bit more chiller capacity than your estimated load? Can we set the chilled water temp lower? I know how load calculations go, I've done them for years. On a 'bad' day what is the loading on the chillers?

So the air inlet is opposite the motor, I assume (which is normal). And a centrifugal fan has a 90 degree inlet to outlet direction. The force (ie... mass) is coming directly at the shaft side of the motor. I think you are correct. I'm assuming a SWSI fan. Single Width, Single Inlet Fan...

Little inch and Novice hit it. Think of it this way, and I'm thinking of a closed loop system (not domestic). The fill pressure is the amount of pressure to lift the water to the highest heating/cooling element in your building with no pumps operating. I then add what I call a flood pressure...

I'm assuming your interested in what happens when you turn one of the parallel pumps off?

Think of pressure developed by the fan in a similar manner as the voltage provided by a battery..

If the installation requires a smoke barrier, I don't think the price difference between a combination fire-smoke damper and a smoke damper is huge. The smoke damper is what drives the major costs. Fire dampers can be fairly simple and be completely standalone requiring no external interface...

Friction loss in pipe as well as dynamic losses at fittings, valves... etc...

LittleInch is revealing the reason (or at least one of them) that autoflow balancing valves were developed. To overcome the manual balancing valves 'fixed' head based at design flow. There are other considerations when using autoflow valves (like two-way modulating control valves and them...

Short answer is you are correct. In order to guarantee flow in the ahu coil you would have to set the remote dp transducer to 33 feet out in the system. Which would cause your balancing valve set lower (closed) to 'eat up' this excess head at the boxes. And I would see the pump not modulating...

Typically in cold climates the drain is for the exhaust air stream and again primarily on plate-type heat exchangers. However wheels can frost as well. Pan and drain used to remove condensate. see link... http://www.greenheck.com/media/pdf/catalogs/ERV_catalog.pdf

Is it possible that a valve, like a fitting is a dynamic (kinetic loss) meaning the V squared thing is still valid, whereas a pipe/tube/heat exchanger/coil also has the 'pipe friction component (ie... a length) which varies as described by f value and others???

I had to go look at Bernie's equation again then to Hazen Williams - then to Darcy Weisbach... Talk about taking a trip in the way back machine. In Darcy which is considered the more accurate of the two, friction is related to the square of the velocity which we would expect... I wonder if...

agreed, combustion blower or draft inducer. If getting really loud there maybe an issue w/ it. have a tech look at.

Try the following link. http://www.greenheck.com/library/articles/40

I was taught the following method by an old timer. You have enthalpy values on the bottom/right side as well as above the saturation curve (diagonal) on your chart. Place your pencil on your point and adjust straight edge until you read the same enthalpy on both 'sides of the chart. One...

The fan will usually have more heat contribution to the airstream than the motor. A 65% mechanical eff. fan will add 35% of shaft power as heat. At 90% efficient motor would add 10% of the motor power output as heat if located w/in the airstream.