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Posted by geoman on July 6, 2006, 7:58 pm
>
>>
>>>We are hooking up a unit that was relocated. In the piping they have a
>>>refrigerant heat exchanger from liquid to suction.
>>>
>>>Air cooled Copeland, inside unit outside they want us to convert.
>>>
>>>I stated that they have to put a fan on the compressor, put a suction
>>>line
>>>accumulator on it, crankcase heater and fan cycling since it gets zero up
>>>here in Ohio. BTW, its 404A
>>>
>>>Question is, Didn't Jim Lavell (Spelling) once say he didn't like heat
>>>exchangers on the new refrigerants? Should I take it out?
>>>What's the rules for heat exchangers?
>>>
>>>I think Jim may have stated that it could be a problem with those with
>>>glides but I can't remember. Heck, I'm not sure if it was Jim that
>>>mentioned
>>>it either, but I know I heard it.
>>>
>>>Thanks
>>>Rich
>>>
>> Keep the HX it increases efficiency, forget about adding a head fan if
>> the compressor didnt come with one you dont need it, use a headmaster
>> instead of fan cycling.
>
>
> Exerts From Copeland Refrigeration Manual
> EFFECT of SUB-COOLING LIQUID REFRIGERANT
> By Superheating The VAPOR.
> A suction gas to liquid refrigerant heat exchanger is
> frequently used for the "FOLLOWING REASONS"
>
> 1 To raise the temperature of retune suction gas So
> frosting or condensation will not occur on the suction line.
>
> 2 To sub-cool the liquid refrigerant sufficiently to offset any pressure
> drop that might occur in the liquid line, and prevent formation
> of flash gas in the liquid line.
>
> 3 To provide a source of heat to evaporate any liquid refrigerant
> which might have flooded through the evaporator, thus
> preventing the return of liquid refrigerant to crankcase.
>
> 4 To increase total system capacity.
>
> Now question is do you need increase in capacity?
> As for compressor head fan you do not needed for that condition.
> If you want good working system you need both controls on
> condenser fan, pressure switch and head master ?
> Switch alone to much fluctuation in liquid pressure.
> Head master alone it require large receiver to store the gas,
> doing hot summer days, and in winter must have some reserve
> around 20% to maintain effective cooling, it also must be able to store
> what ever is in the condenser and evaporator, by use of both controls
> you can reduce size of receiver and refrigerant from 1/4 to 1/3 of
> capacity been used. However everybody have they own opinion and
> I am talking from my own experience.
>
> Dido say that
> www.cas-environ.com
I know all of this, and once again, I'm specifically asking about the sub
cooler with some of the new refrigerants. I remember explicitly that
some manufacture/rep stated that with some refrigerants you do NOT want a
sub-cooler in the line. I believe it was with gas's with a wide
Slide too them. This is the information that I require.
Also, I would love to put a head master control on, but the cost of it with
the additional reciever isn't an option. With an air cooled compressor
however we need air over the compressor. I suppose that if the owner doesn't
want to pay for it he will buy a compressor sooner from me than he wish's,
but I'm not putting one on without them paying for it.
Back to the question:
Considering the new refrigerants, what refrigerants should you NOT use a sub
cooler with?
RIch
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