Does anybody know the metering devices used for this heat pump?
Their location would be helpful as well.
Whilst replacing the evap coil, we found that the old unit had NO
orifice. The instructions for the new one called for an orifice.
How could the old one have worked? It was maybe eight years
old.
Do they have some kind of bi-flow out at the heat pump?
Double-metering wouldn't be good.
Outdoor unit has a TXV for heating only. Indoor is a TXV or piston. If you found no metering device inside and just added one you will probably be replacing the compressor soon.
It's just the nature of the beast. I have found this myself.
I failed to mention that the old compressor did indeed die a horrible burnout.
But it evidently worked for eight or so years as a heat pump & a/c.
When pressure-testing the heat pump, we found the strange damage to
the evap coil and replaced that.
The fact that the thing worked for eight years leads one to suspect
that the metering device for the indoor coil was not where it was supposed
to be. Else a metering device is optional except for the small matter
of compressor longevity? Strange.
I replied to the first reply as the second reply was being posted.
So we have two seasoned ones in agreement that the indoor unit
needed an orifice. The outdoor unit did indeed have a TXV.
Thank you. I feel better, I think.
The replacement compressor appears to not be compressing.
At least we can be confident that it wasn't related to double-metering.
What are the odds that a replacement compressor could have such
an issue?
What are the odds that a replacement compressor could have such
an issue?
That is always a coin toss.
I think this outside unit might have come with a filter dryer installed on the liquid line inside the cabinet, before the TXV. Be sure to check that, and replace it, if it is the case.
Instead of learning the tricks of the trade, learn the trade.
Yes, I did the compressor change-out. I had first thought the muffler
was a filter-drier, until I removed it and read "muffler" on the side. Duh.
Then I found the real filter drier and replaced it with copper tubing.
Installed a large bi-flow on the liquid line.
I have had indoor units with no metering device. It is suppose to have one one. Installers just forget to put them in. For some reason it cools somewhat. I forget what my superheat and sub oolong has been.
This was a burnout? Did you follow burnout procedures? HH driers and replacing them? Maybe reversing valve and check valves have trash in them?
I have had indoor units with no metering device. It is suppose to have one one. Installers just forget to put them in. For some reason it cools somewhat. I forget what my superheat and sub oolong has been.
This was a burnout? Did you follow burnout procedures? HH driers and replacing them? Maybe reversing valve and check valves have trash in them?
New LL drier. No suction line drier. I blew a ton of nitrogen through it.
Put some acid neutralizer snakeoil in the system. Replaced the evap coil.
The senior tech doesn't seem to think there is an obstruction.
We shall see and I'll report back when we do. It might be
a week or so.
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Originally Posted by georgelass
