Heat Pump, After major burnout.

[georgelass]

I've already posted two questions about heat pumps this weekend,
so I know I'm pushing my luck, perhaps squeezing the good-nature
of the helpful forum veterans. Sorry, but this one may save some
more pain.

We have a Trane heat pump. Major compressor burnout.
The thing even blew a hole through one of the electrical
terminals at the compressor. Very stinky.

Compressor was changed. Evap coil was changed. It had
a big leak and a bunch of fins were dissolved--nobody
really can figure that one out.

Changed the compressor, of course. As stated in earlier
post, little filter-drier was removed and big blue 163S was
put on the liquid line. Much, much purging with nitrogen.
Used the acid-neutralizer stuff for good measure and
superstition.

Put on gauges, start unit in cooling. Gauges don't budge.
Check reversing valve. 24 V at wires to solenoid.
Remove wires. Add. Remove. Add. Rap on reversing valve
body with large crescent. Clicks but no wooshing.
Three of the four reversing valve appendages were
very warm. Fourth closer to ambient of maybe 53 F.
Based on my assumption that a max of two appendages
should be warm, I concluded the reversing valve is bad.
We will schedule a replacement pursuant to senior tech
approval.

My question is whether even with such major reversing
valve failure, could THAT account for the gauges not budging
the needles, or should we also suspect check valves are
stuck open? (In case you haven't seen my recent posts,
you should know that I don't have experience with
such problems on heat pumps, that I'm only going
with what I've read.)

One more possibly relevant point. The outside unit has
a TXV. When we changed the inside coil, we noted it did
NOT, absolutely, no mistake, did NOT have an orifice.
The coil installation instructions and Trane Help-line both
said it SHOULD have an orifice and specified its location.
We obtained and installed the orifice. Senior tech
said he did not know how it could have functioned without
an orifice. We did not ever observe operation of the unit
prior to the burnout, so we can't say how it functioned,
good or bad.

Is the reversing valve replacement likely to bring total success?
Thank you all.

[cjpwalker]

Which pipes were hot? Where were your gauges attached?

Also I have seen a system operate without a piston or txv before. Pressures and temps look like crap but it will cool. There is enough pressure drop across the distributor tubes and through the coil to get refrigeration.

Sometimes if you get a strong enough magnet you can force that valve to shift. You also might try stopping the fans to get your pressure up and force that valve to seat on its own. I don't know your experience level, but are you familiar with the internals of these valves and how they function?

[SBKold]

Rev valves can be damaged during compressor failure.

Believe it or not compressor manufacture actually recommends new accumulator and Rev valve on every burn.

[georgelass]

I had my gauges low-side on suction and high-side on liquid...service valves
as one would with typical a/c. No, I didn't actually write down the pressures.
Hot pipes were the top one and the two on the left. The one on the right, I believe
it went to the evap coil, it was about ambient. I didn't put a thermocouple on any
of them.

I've seen a cutaway of reversing valves. I understand they need the pressure to make them
switch, that the solenoid just opens/closes the little tubes.

This compressor was a warranty replacment. I didn't talk to Trane but I'm sure our boss
would have gladly accepted a reversing valve were it offered. The owner was not interested
in paying for anything that wasn't absolutely necessary.

So the gauges not budging could be blamed entirely on the reversing valve? The check
valves are not a concern?

Thank you.

[Push It]

This compressor was a warranty replacment. I didn't talk to Trane but I'm sure our boss
would have gladly accepted a reversing valve were it offered. The owner was not interested
in paying for anything that wasn't absolutely necessary.

So the compressor was under warranty but the RV was not? I would have stated in the quote that the RV should be replaced and that a suction line filter drier must be installed at a minimum. Also state several filter drier changes may be needed and after start up that all valves(TXV, check) will be tested for proper operation and recommendations made if replacement is needed.

No orifice is what caused the compressor failure.

Good luck, add that suction line filter drier when you replace the reversing valve.

[georgelass]

I think that if we had our druthers, we would have simply got a new condenser unit rather
than remove the old copper filter-drier, the reversing valve, maybe the TXV, and the
compressor. But the owner didn't want to pay for anything but the most basic of labor,
and we couldn't guarantee him that anything was wrong except the compressor.
I don't believe he was interested in likelihoods. Our senior tech agreed that the no orifice
was the likely killer. It did last for eight years without raising any eyebrows.

Over the years, our company has evidently done a bunch of compressor burnouts
without having to do the much more expensive suction line filter drier additions and
removals, and everything worked out fine from most accounts. It is hard to tell
the customer that they will need all of that extra work a couple of weeks down the
road so we don't try. Like I said, they have managed thus far even though in an
ideal world, the recommendation would be otherwise.

[Snapperhead]

Sounds like when you find the problem , you will then know WHY the compressor went bad in the first place ....

[toocoolforschool]

You might have some clogged check valves and filter driers if they weren't changed too.

[crazzycajun]

A 163s drier how about a bi flow not your main problem however

[georgelass]

A 163s drier how about a bi flow not your main problem however

I thought the 163S was simply the 4-ton, 3/8 inch, sweat, and then it came in
uni- and bi-flow?

[garyed]

One of the problems dealing with heat pumps is that there is no way to know if the RV if good without a good running compressor. I got in the habit of whenever a compressor goes bad to tell the customer that there is always a possibility of a bad RV that caused the problem but no way to be sure until the compressor is replaced. There's always other possible causes of the compressor damage but an RV is the one I fear the most.

[beenthere]

An RV stuck in the middle will cause the head and vapor pressures to be the same while the compressor runs. can also cause the comp to over heat and eventually fail.

163S is just the size of filter, and sweat connection indication, weather bi flo or not the designation doesn't tell you.

[crazzycajun]

I didn't see the hpc in the post i assumed just regular 163 my appologies to the op