Digital Zeus™ HVAC Tool & Instruments Journal

More colors listed than colors at the bottom. Was running 2 temp humidity wirless probes will try and send the pdf on all the temp’s. It’s a Luxaire 2.5 ton heat pump with expansion valve. 10 degrees of subcooling. Just started working with these charts will try and get the other out. Humidity inside and outside with indoor and outdoor temps.

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Winner of the ACHR NEWS® 2005 Dealer Design Award, the SG3000™ - contrary to popular misconception is not a new instrument. It’s technology is fully patented. With over 2 years of research and development invested in it’s refinement.

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If you are not familiar yet with the SG3000™ - watch the clips below. Then join and participate in our member FieldTests yourself.

Review the SG3000™ User’s Guide in Zeus’ Black Box, right hand column lower section of the page.

External Static Duct Pressure

- Using your Combustion Air Analyzer to determine External Static Pressure -

Probably one of the most frequently ignored factors in setting up a duct system is the external static duct pressure (ESP).

In years past the temperature rise or drop across the coil or heat exchanger could verify that the air flow was in the ‘ballpark’, but with the higher efficiencies, particularly of air conditioning systems and heat pumps, air flow becomes absolutely critical. In fact, if the air flow is not per manufacturers recommendations, it is impossible to even get the refrigerant charge correct.

Ironically, measuring ESP is a fairly simple procedure and, in all likelihood, will result in increasing customer satisfaction with the system’s performance, comfort and efficiency as well as find more work on a jobsite. Several studies have concluded that most heat pump and air conditioning systems have duct systems that are inadequate to supply sufficient air flow.

To correctly measure ESP, a static pressure tip is used in conjunction with a pressure gauge capable of reading in the hundredths of a water column inch. Bacharach’s electronic instruments which measure differential pressure (typically used for draft measurements), can measure ESP.

The two Bacharach combustion test instruments commonly used to measure ESP are the PCA 25 (and higher series) or the Fyrite Pro 125.

PCA 25

Fyrite Pro 125

In the photo’s above, the differential pressure taps are the two on the right hand side, the port on the left hand side is for sampling combustion gases.

This Article provided courtesy Bacharach® Instruments. For the rest of this Article: http://hvacprotech.forumwise.com/hvacprotech-post-11130.html#11130

Measure Duct Loss in Five Minutes
Rob Falke 

“We’ve all heard our customers describe how the air conditioning system works well in the morning, but doesn’t deliver any cooling in the afternoon. We send out a service tech, he services the unit and reports that it’s working pretty well. End of story, right? Well, not for the customer. He or she is still uncomfortable every afternoon until the weather cools down in the fall. Why does this happen? The most likely reason is duct loss.
Ideally, the temperature of the air leaving the equipment should be the same as the air leaving the farthest supply grille. But if the duct is running through a 140F attic, it’s not uncommon for supply air to lose up to half of its Btus of cooling.

Let’s take a look and discover how a simple five minute test can quantify the duct loss and help us solve a problem that may have been overlooked for years. But you won’t find the answer to this question at the unit. You’ve got to pull your head out of the box and check the duct system.

Check the Delta T
Delta T is the difference between any two related temperatures. Checking it is easy and quick: simply take two temperature readings, and subtract one from the other.”

Lets take a closer look at that idea and plot it out on a psychrometric chart
The first photo is a plot of the conditions as stated.

Click the Image for more Detail

Read the Rest of this Discussion and Articles: http://hvacprotech.forumwise.com/hvacprotech-thread4176.html