Recent content by jvithayapun

so does that mean you would get the rated max cooling only at the highest fan speed?

If an indoor unit is rated for 7500 btu/h cooling capacity, and has 3 fan speeds of 212/282/353 cfm. Does this mean that Only the highest fan speed of 353 cfm will provide 7500 btu/h of cooling? If so, how would I calculate how much cooling the low speed of 212 cfm would provide? thanks!

Im looking at some Carrier condensers and the residential (ex. model 24APA760---30, 5 ton) has a SEER=16, EER=13ish. Then if you look at the commercial models (while it is 1 ton more) a 6 ton unit has an EER=11. I think I have seen this pretty common across the board from different...

is there a website that you could provide? i tried googling it with no luck. thank you.

Im looking for around 15 ton condensing unit with a high SEER/EER rating. Who is leading the pack nowadays in terms of energy efficiency. This will air cooled preferbly r-410.

thanks for the replies. any comments as to why many heaters come preset at 120F though?

yeah, i was thinking about just using 140F at the heater based on ashrae, and then running to mixing valve to bring the temps down. but then it got me thinking why most factory set points of water heaters are 120F if in fact at this temp legionnella is still prone to growing? I have read from...

Im a little confused on what the setpoint for say a standard electric hot water heater for an office building should be which serves sinks and such. I have read in ashrae that 'service water temperature in the 140F range is recommended to limit the potential for Legionella growth'. Ive also...

could be leakage somewhere or static pressure from ductwork. just by looking at random fan curves, a 1 inch increase in static pressure can cause an 8000 cfm decrease.

disregard last post, i found my error. the h that gives me 15.52 is roughly 41db/41wb. i believe this would be correct?

ok, so if i use Qt = cfm * 4.5 * deltaH 24000 = 425 cfm * 4.5 * deltaH deltaH = 12.54 Now assuming EAT=75F at 50% then h=28.15 so 28.15-12.54 = 15.61 = h leaving coil Im looking for some random point with about 100% saturated air and i am coming up with 25 db/ 25 wb that gives me a...

Say a split system is rated at 2 tons Total MBH=24. Assuming the t-stat is set at 75F and the fan in the unit does 425 cfm. So: 24000 = ( 425 cfm) * (1.1) * deltaT Therefore deltaT = 51.33 Does that mean if my room is set to 75, my EAT=75 and my LAT off the coil is (75-51.33)=23.7F? Im...

I have yet to read through everyone else's reply so what I type might either agree or conflict. But in VAV systems the box can be equipped with a hot water or electric heating coil to heat back up the air that has essentially been 'overcooled' due to air changes. As far as the outside air...

I have tried looking and found a range b/w 80-130F as a good heating discharge temperature. I have also read that aiming for 105F is a good spot. When adjusting the heating cfm, do you adjust it up and down until the discharge temperature reaches a certain temperature you are aiming for? And...

Does anyone know where a specification for these systems can be found?