student w/ a compressor ?

[kywhiskey]

im currently a student in a hvac program in Louisville KY.i have a question on a study sheet that i d like y,alls help with. a compressor that has a broken valve will cause these symptoms? a. high suction pressure/low discharge pressure b.high suction/ high discharge pressure c.low suction/ low discharge pressure d. low suction/ high discharge pressure? I thank y all for any and all responses

[HVAC Pro]

a. now why couldn't you find that in the book? :D

[dschwab9]

Think about it a minute, and I think you'll answer your own question. Broken valve means you lose pumping capacity on that cylinder? Right?

So, you now have a compressor that's pumping a lot less volume than it should. What's that going to do to your operating pressures assuming everything else in the system remains the same?

[midhvac]

That could depend on where that broken valve ends up :)

[kywhiskey]

thank you both 4 helping me with my ?. you both are right i didnt think the question thru an research it more. please dont think im a guy on here looking 4 others to do my homework i do study hard im universally certified EPA an passed my basic electricity ESCO certified but i did take the easy way out and got on here and asked 4 an answer that i should have studied 4 ty again

[HVAC Pro]

Originally posted by kywhiskey
i do study hard im universally certified EPA an passed my basic electricity ESCO certified

Good job! Keep up the hard work...

[mattm]

Do you make your own whiskey?

[Shophound]

thank you both 4 helping me with my ?.

I know it sounds nit picky, but I'm curious as to why you'll spell out every other word in your post but "for" and "question"? :confused:

As for your question, think about a system that is idle and has been for some time. You have your gauges on it and you flip up the disconnect. Compressor kicks on and runs. You watch gauges and something seems wrong. Suction pressure doesn't seem to be pulling down to a normal range and head pressure doesn't seem to be rising to a normal range. You place your amp clamp on the run or common lead to the compressor and you get a low amperage reading. You then close the liquid line base valve on the condensing unit (split system) and attempt to pump down the liquid line, evaporator, and suction line into the condenser. You notice that this process occurs slowly or not at all.

Oh...I just realized I gave you a service tech's answer to your question, vs. a textbook answer. Of course, the scenario I described above doens't apply only to bad compressor valves. Incorrectly sized piston metering device, TXV stuck full open, etc might also render high suction/low head, but a pumpdown test would eliminate the compressor as being at fault and cause your focus to shift elsewhere. It is not unheard of for a tech to slap his gauges on a system, get a reading of high suction/low head, condemn and change out the compressor, only to fire it up and still have the same problem! :eek:

[Green Mountain]

It is not a pump it is a compressor. The school I went to taught us that a compressor becomes a pump just before it becomes a wreck.:)

[dschwab9]

Originally posted by benncool
It is not a pump it is a compressor. The school I went to taught us that a compressor becomes a pump just before it becomes a wreck.:)

LOL. That's a good one.