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Pre-charged heat pumps - ever see one over charged???

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Pre-charged heat pumps - ever see one over charged??? Kettering 03-05-2007
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Posted by on March 6, 2007, 10:55 pm

> >
> >
> > > Did an install on a Rheem 4T RPNE. Factory says to add .6 oz/ft. over
> > > 15'. OK, I pulled her down to <500 microns and added exactly 21 oz
> > > gas. (ie 50-15 X.6 oz)
> >
> > > Now I fire her up and she runs about a minute of two and shuts off
> > > while AH continues to go. "Y" remains hot.
> >
> > > Now I hook up the guages and low is about 65 PSI and hi goes upwards
> > > of 300 PSI!!!.
> >
> > > OK now I recover the refrigerant and add enough back in to to bring it
> > > to the Rheem chart. Now it's about 40-45 PSI low/200-210 PSI hi at
> > > about 50 ambient and 65 IDB. It's producing about 25-30 heat rise
> > > over the coil.
> >
> > Whats your subcooling??
> >
> >
> >
> > > Have you ever seen the factory charge this far off?? Does elevation
> > > affect factory charge that much? (site is at 1500')- Hide quoted
text -
> >
> > - Show quoted text -
>
> Subcooling isn't valid for a HP running in heat mode. He could use the
> Lennox method of heating the home with aux. heat then blocking off the
> condenser and running it in AC mode to get his subcooling reading.
> Superheat won't tell him anything either since his indoor coil has a
> TXV.


We all know we charge by SC on a TXV system, but knowing the SH is valuable
data for troubleshooting.




Posted by Bob Pietrangelo on March 6, 2007, 9:45 am

> Did an install on a Rheem 4T RPNE. Factory says to add .6 oz/ft. over
> 15'. OK, I pulled her down to <500 microns and added exactly 21 oz
> gas. (ie 50-15 X.6 oz)
>
> Now I fire her up and she runs about a minute of two and shuts off
> while AH continues to go. "Y" remains hot.
>
> Now I hook up the guages and low is about 65 PSI and hi goes upwards
> of 300 PSI!!!.
>
> OK now I recover the refrigerant and add enough back in to to bring it
> to the Rheem chart. Now it's about 40-45 PSI low/200-210 PSI hi at
> about 50 ambient and 65 IDB. It's producing about 25-30 heat rise
> over the coil.
>
> Have you ever seen the factory charge this far off?? Does elevation
> affect factory charge that much? (site is at 1500')


Ever see something other than the charge cause bad pressures????????



Posted by on March 6, 2007, 8:01 pm

>Did an install on a Rheem 4T RPNE. Factory says to add .6 oz/ft. over
>15'. OK, I pulled her down to <500 microns and added exactly 21 oz
>gas. (ie 50-15 X.6 oz)



what method of charging did you use to add exactly 21 oz of gas?





>
>Now I fire her up and she runs about a minute of two and shuts off
>while AH continues to go. "Y" remains hot.
>
>Now I hook up the guages and low is about 65 PSI and hi goes upwards
>of 300 PSI!!!.
>
>OK now I recover the refrigerant and add enough back in to to bring it
>to the Rheem chart. Now it's about 40-45 PSI low/200-210 PSI hi at
>about 50 ambient and 65 IDB. It's producing about 25-30 heat rise
>over the coil.
>
>Have you ever seen the factory charge this far off?? Does elevation
>affect factory charge that much? (site is at 1500')
>
>
>
>
>
>


Posted by Deke on March 7, 2007, 8:36 am

>Did an install on a Rheem 4T RPNE. Factory says to add .6 oz/ft. over
>15'. OK, I pulled her down to <500 microns and added exactly 21 oz
>gas. (ie 50-15 X.6 oz)
>
>Now I fire her up and she runs about a minute of two and shuts off
>while AH continues to go. "Y" remains hot.
>
>Now I hook up the guages and low is about 65 PSI and hi goes upwards
>of 300 PSI!!!.
>
>OK now I recover the refrigerant and add enough back in to to bring it
>to the Rheem chart. Now it's about 40-45 PSI low/200-210 PSI hi at
>about 50 ambient and 65 IDB. It's producing about 25-30 heat rise
>over the coil.
>
>Have you ever seen the factory charge this far off?? Does elevation
>affect factory charge that much? (site is at 1500')

I say you have a restriction and the problem (lack of cooling) will
show up come summer.


>
>
>
>
>
>


Posted by Kettering on March 7, 2007, 9:55 pm
Then why would a restriction magiclly vanish with a slightly lower
refrigerant charge?


>
>>Did an install on a Rheem 4T RPNE. Factory says to add .6 oz/ft. over
>>15'. OK, I pulled her down to <500 microns and added exactly 21 oz
>>gas. (ie 50-15 X.6 oz)
>>
>>Now I fire her up and she runs about a minute of two and shuts off
>>while AH continues to go. "Y" remains hot.
>>
>>Now I hook up the guages and low is about 65 PSI and hi goes upwards
>>of 300 PSI!!!.
>>
>>OK now I recover the refrigerant and add enough back in to to bring it
>>to the Rheem chart. Now it's about 40-45 PSI low/200-210 PSI hi at
>>about 50 ambient and 65 IDB. It's producing about 25-30 heat rise
>>over the coil.
>>
>>Have you ever seen the factory charge this far off?? Does elevation
>>affect factory charge that much? (site is at 1500')
>
> I say you have a restriction and the problem (lack of cooling) will
>show up come summer.
>
>
>>
>>
>>
>>
>>
>>


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