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Posted by Bubba on December 28, 2007, 6:46 pm
wrote:
>I doubt plugged pilot lines are the problem - at least I've never found any.
Well maybe your eye are old and you need glasses? :-)
>The pilot lines see a pressure difference equal to the difference between
>suction an discharge, so its tough to plug em.
Never say never. It'll get you everytime
>Given the age, I would
>suspect wear or debris on the main piston/slide/shuttle , gummed-up or
>damaged plastic or rubber on either the pilot or main or a plugged bleed
>hole on the pilot.
Didnt you just say up top that pilots dont plug?
And the op did say the piston slid freely and with authority
> As to repeat failure - these things are installed in a
>position so they are damn tough to just replace using all the original
>fittings only without damaging the valve. I typically play it safe and add
>a couple (or sometimes more) couplings as needed in a place that's
>accessible and braze the valve with 50-60% silver with the valve completely
>out in the open, then do the couplings with the valve installed. Also -
>doing this frees you from the need to use the OEM valve - the old monsters
>especially cost about the same as a compressor.
Yup, same way I do them but I use the valve recommended. I also braze
(not solder) with the sticks, Dynaflow, Stay-silv 6 of 15 I believe
its called.
Bubba
>
>
>> On Fri, 28 Dec 2007 19:20:58 -0000, "Lloyd E. Sponenburgh"
>> <lloydspinsidemindspring.com> wrote:
>>
>>>I just replaced the reversing valve on an old Tempstar package unit.
>>>DAMN... the cost of the job would've half replaced the unit, but the
>>>owner sez no. So you do the work, and only warrant that part, no?
>>>
>>>It's a pilot-operated valve.
>>>
>>>Anyway, what I am curious is, what is the mode of failure on these
>>>valves? One assumption I could make is that one of the pilot lines -
>>>almost as small as capillary tubing - has become clogged. The armature
>>>in the pilot valve moves freely and hits both seats with authority.
>>>
>>>If there isn't a general consensus on why these fail, I'll probably
>>>dissect it on my own time to try and figure it out.
>>>
>>>And no, I don't want to fix it. I just want to understand why it failed.
>>>If they do fail from grod in the pilot lines, it seems to me it's just an
>>>invitation for a new valve to fail in the same way.
>>>
>>>Ideas?
>>>
>>>LLoyd
>>
>> Exactly why any refrigeration system needs to have someone follow
>> proper brazing practices, driers, charging, evacuation and servicing.
>> If it were that easy, everyone would be doing it.
>> Bubba
>
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