Originally Posted by
elevatedvagabond
Ruud AHU
m)UBHC14J07NFA
Delta T on high speed 8*F/ low speed 15.5*F
Can somebody please tell me where my mistakes are on the heat rise method?
I'm going with measurement errors. Are you sure about those ∆T's ?
Lets look at an example with the nominal 800 cfm on high speed, with your 7,000 watt heat strips.
∆T = BTUH/1.08 x 800 cfm
∆T = BTUH/864
7000 watts x 3.413 = 23891 btuh
23891 / 864 = 28ºf ∆T
Your system test is only showing a 8ºf ∆T on high.
Using your volts and amps, and assuming 800 cfm, you should have something like this:
245 volts x 26.5 amps = 6493 watts
6493 watts x 3.413 = 22160 btuh
22160 / 864 = 25ºf ∆T
Instead of learning the tricks of the trade, learn the trade.