Wet bulb / dry bulb

1511 Views 15 Replies 7 Participants Last post by DOUG1111, Mar 8, 2016

DOUG1111

Discussion Starter · Mar 6, 2016

The difference in #s (spread)Wet bulb temp #s & dry bulb temp #s???? Is there an average/ norm/ about/ should be/ #?? Example: Wet bulb temp @ return air should be approximately between____ & ____ lower than dry bulb temp @ return air.. OK if #s too high (spread) what to look for?? If #s too low (spread) what to look for??

1 - 16 of 16 Posts

gregzoll

· #2 · Mar 6, 2016

One is actual temperature vs. the temperature with humidity. The difference between the two is what gives you the Dew Point. We are talking about Second grade science here, if even that these days.

All that you had to do was search at noaa.gov or online for the answer. I did not even have to search, since this is the most simple thing in life to understand how it works.

beenthere

· #3 · Mar 6, 2016

gregzoll said:
One is actual temperature vs. the temperature with humidity. The difference between the two is what gives you the Dew Point. We are talking about Second grade science here, if even that these days.

All that you had to do was search at noaa.gov or online for the answer. I did not even have to search, since this is the most simple thing in life to understand how it works.

Doug is asking what the wetbulb depression range should be, not what wet bulb is. So I take it, that you don't know what the wetbulb depression range should be either.

Reactions: 1

beenthere

· #4 · Mar 6, 2016

DOUG1111 said:
The difference in #s (spread)Wet bulb temp #s & dry bulb temp #s???? Is there an average/ norm/ about/ should be/ #?? Example: Wet bulb temp @ return air should be approximately between____ & ____ lower than dry bulb temp @ return air.. OK if #s too high (spread) what to look for?? If #s too low (spread) what to look for??

At human comfort temps, the depression in the home/building, or the return duct should be between 10 and 15. The lower the drybulb, the shorter the depression range.

Depression can be used on both the supply and return. And each gives indications if the A/C is or isn't working like it should.

In the supply duct, a depression of 4 to 6 is good.

Reactions: 2

Bob Sanders

· #5 · Mar 6, 2016

gregzoll said:
One is actual temperature vs. the temperature with humidity. The difference between the two is what gives you the Dew Point. We are talking about Second grade science here, if even that these days.

All that you had to do was search at noaa.gov or online for the answer. I did not even have to search, since this is the most simple thing in life to understand how it works.

This is just uncalled for and it pisses me off to no end.

A diy'er has asked a question and this is a DIY site. The answer may seem simple to you but that doesn't mean it is simple to others. (even though you completely misread it). If you want to give people a whole pile of mouth for asking legitimate questions then go somewhere else.

Reactions: 3

user_12345a

· #6 · Mar 6, 2016

There is no normal, no should - it is what it is.

Return air wet and drybulb temps will vary a lot.

There are charts that tell you what the supply air drybulb should be at x return air wetbulb/drybulb - those are useful, but that all hinges on proper airflow across the coil.

SeniorSitizen

· #7 · Mar 6, 2016

Bob Sanders said:
If you want to give people a whole pile of mouth for asking legitimate questions then go somewhere else.

Especially if you had to repeat second grade. LMAO

yuri

· #8 · Mar 6, 2016

Gregzoll has been here a LONG time with no bad attitude. I suspect the Trump/GOP biz is bothering a lot of people and creating snark-i-ness.:devil3:

Reactions: 2

gregzoll

· #9 · Mar 6, 2016

beenthere said:
Doug is asking what the wetbulb depression range should be, not what wet bulb is. So I take it, that you don't know what the wetbulb depression range should be either.

I did not catch that, since I am still using my phone to go online, since my right eye had the bigger Cataract and is still not fully focusing. Add in a coffee cup of Dewer's when I saw this.

I never understood the whole depression thing, but always knew the other, since it is a lot easier to figure.

gregzoll

· #10 · Mar 6, 2016

Yuri I am not even paying attention to this year's run. Yes I am getting really tired of it by now and wanting it over.

DOUG1111

Discussion Starter · #11 · Mar 6, 2016

Wb/db

beenthere said:
At human comfort temps, the depression in the home/building, or the return duct should be between 10 and 15. The lower the drybulb, the shorter the depression range.

Depression can be used on both the supply and return. And each gives indications if the A/C is or isn't working like it should.

In the supply duct, a depression of 4 to 6 is good.

Thank you for the info!! I was thinking my friend checking that the WB sock may have dried out

Reactions: 1

beenthere

· #12 · Mar 6, 2016

While I still have a wet sock sling. I use my digital mostly. So I don't have to worry about the sock drying out, and not having anymore distilled water with me.

Reactions: 2

user_12345a

· #13 · Mar 7, 2016

^Does it have to be distilled to get an accurate reading? How much would tap water throw it off?

DOUG1111

Discussion Starter · #14 · Mar 7, 2016

user_12345a said:
^Does it have to be distilled to get an accurate reading? How much would tap water throw it off?

Good question!! I did not know about the distilled water. I use feildpeace digital. Comments on poor mans WB thermometer= stem thermometer with sock /shoe string/ t-shirt hem over the stem???

Reactions: 1

beenthere

· #15 · Mar 7, 2016

user_12345a said:
^Does it have to be distilled to get an accurate reading? How much would tap water throw it off?

Couple degrees, after a few months of using tap water. The minerals can insulate the bulb so it reads high.

Reactions: 1

DOUG1111

Discussion Starter · #16 · Mar 8, 2016

Good info!!! Thanks everyone!!!!!!!

Reactions: 1

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