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Posted by Zyp on February 27, 2008, 12:04 pm
Marc O'Brien wrote:
> On Feb 26, 3:30 am, .p.jm@see_my_sig_for_address.com wrote:
>>> Tony wrote:
>>>> Taken in consideration what stormin and zyp told you
>>>> I believe that EPR valve are still being made
>>>> tony
>>
>>
>>>>>> I poped back in to see how this cellar cooler system was doing
>>>>>> after my repairs.
>>
>>>>>> It's iced again but this time the full charge still exists,
>>>>>> subcool remains sufficient.
>>
>>>>>> It's design saturated evaporating temperature is about 4 deg C,
>>>>>> however, surely, due to an inefficient compressor the lower
>>>>>> evaporator circuit freezes?
>>
>>>>> Add a hot gas bypass and solenoid.
>>
>>> For the first time in how many month's, I actually understood what
>>> Tony said. An EPR valve might help here.
>>
>> At the risk of short cycling. I always hesitate to look at
>> 'solutions' that involve re-engineering the system.
>
> Indeed, keep it simple stupid. The irony is that one has to know an
> aweful lot more each time one wants to further simplify something.
> Like the saying "Sorry my letter to you is so long but I didn't have
> the time to write a shorter one".
>
> An EPR reduces evaporator volume flow which is precisely not what you
> want if your problem is already too little evaporator volume flow.
I'm not sure his problem stems from evaporator flow. It seems to me that
when the fixture temperature is just above freeze point, and the evaporator
is below freeze point, you're getting frost no matter what you do. At least
an EPR could keep the evaporator from reaching that point. [Albeit - it is
already a case of refrigeration effect being lost because of the saturation
temperature and flow.] Perhaps just simply execute a defrost every 3-4
hours for 20 minutes would be sufficient. It depends on his load for the
fixture, no?
--
Zyp
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