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  1. #27
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    I'm confused just a little here.

    If you had 1 lb of 211*F water,then you add just 1 BTU to make that 1 lb of 211*F water into 1 lb of 212*F water. Then you need 970 more BTU to change that 1 lb of 212*F water into 212*F steam.

    If starting at 32*F water w/ 1 lb of water,there is needed 180 BTU to raise that 1 lb of 32*F water into 1 lb of 212*F water.Then the same 970 btu is needed for the change of state into 212*F steam.

  2. #28
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    Putting way too much lipstick on this pig

    Sent from my XT1710-02 using Tapatalk

  3. #29
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    Quote Originally Posted by JeffWil View Post
    Putting way too much lipstick on this pig

    Sent from my XT1710-02 using Tapatalk
    There were a few diff versions of the amount of BTU required and how many "times" the amount of BTU needed for the change of state. They are all correct?

  4. #30
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    No, but the OP is a younger tech, and hitting him with the exact BTU properties to change ice to steam is way above his questions regarding superheat. While I understand it's relativity, and many others do it is just way over what he's asking and could just flat out confuse him.

    Sent from my XT1710-02 using Tapatalk

  5. #31
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    Quote Originally Posted by TechmanTerry View Post
    I'm confused just a little here.

    If you had 1 lb of 211*F water,then you add just 1 BTU to make that 1 lb of 211*F water into 1 lb of 212*F water. Then you need 970 more BTU to change that 1 lb of 212*F water into 212*F steam.

    If starting at 32*F water w/ 1 lb of water,there is needed 180 BTU to raise that 1 lb of 32*F water into 1 lb of 212*F water.Then the same 970 btu is needed for the change of state into 212*F steam.
    no confusion at all Terry. this is the laws of physics and the basis of many HVAC heating and cooling mediums. steam heat and refrigeration. its written in many many textbooks. you do read all these textbooks you speak of?

    Quote Originally Posted by JeffWil View Post
    No, but the OP is a younger tech, and hitting him with the exact BTU properties to change ice to steam is way above his questions regarding superheat. While I understand it's relativity, and many others do it is just way over what he's asking and could just flat out confuse him.

    Sent from my XT1710-02 using Tapatalk
    maybe i did go in a bit deep for a newer tech ( the op) but someone else responded with incorrect information. nothing can be worse to a new guy trying to learn. he did ask about 970.
    my boss thinks its possible to repeal the laws of physics

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  7. #32
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    Quote Originally Posted by ch4man View Post
    no confusion at all Terry. this is the laws of physics and the basis of many HVAC heating and cooling mediums. steam heat and refrigeration. its written in many many textbooks. you do read all these textbooks you speak of?



    maybe i did go in a bit deep for a newer tech ( the op) but someone else responded with incorrect information. nothing can be worse to a new guy trying to learn. he did ask about 970.
    Yes sir I agree, and yes your info is correct in comparison to the original information posted on said subject.

    Sent from my XT1710-02 using Tapatalk

  8. #33
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    Quote Originally Posted by TechmanTerry View Post
    I'm confused just a little here.

    If you had 1 lb of 211*F water,then you add just 1 BTU to make that 1 lb of 211*F water into 1 lb of 212*F water. Then you need 970 more BTU to change that 1 lb of 212*F water into 212*F steam.

    If starting at 32*F water w/ 1 lb of water,there is needed 180 BTU to raise that 1 lb of 32*F water into 1 lb of 212*F water.Then the same 970 btu is needed for the change of state into 212*F steam.
    you know Terry, now I'm confused. is the quoted post a question or statement??
    my boss thinks its possible to repeal the laws of physics

  9. #34
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    Jun 2011
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    Quote Originally Posted by Buckeye88 View Post
    However I guess with low superheat that would mean the coil isn’t doing it’s job in absorbing heat.
    it is possible that if there is enough refrigerant liquid / gas mixture entering the evaporator coil it could be boiling / " changing state " the entire time from the inlet of the evaporator coil to the outlet of the evaporator coil and you would have ZERO superheat ......

    and while the refrigerant liquid / gas mixture is boiling / " changing state " the refrigerant liquid / gas mixture remains the same temperature ..... but it is still absorbing a lot of heat from the air being blown across the coil .....

    https://www.achrnews.com/articles/94...ng-made-simple

    it is absolutely critical you understand this .....

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  11. #35
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    Nov 2016
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    Quote Originally Posted by Buckeye88 View Post
    I am a new tech a little confused about a call I ran today. It was a unit with a piston and R22. When I first put my gauges on I was was getting readings for around 28 degree evaporator coil. The supply air was around 82 or so. Now when I added refrigerant and brought up the evaporator temp to around 42 the supply temperature dropped to somewhere in the 60s.

    I have been confused about why this is and why the supply temp would be so high when the coil was low originally. The coil wasn’t frozen as the unit had been off. If anyone can help me understand I’d appreciate it.
    Low juice in the evap means no heat is being absorbed or very very little and air is just being sent out just as it came in.

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