Heat Pump Metering Device (indoor unit)

[greenhorn520]

Is this an orifice or capillary tube metering device and why is there no check valve?

[Pascone10]

Is this an orifice or capillary tube metering device and why is there no check valve?

Are you in the Trade? We can't give much technical advice to homeowners..

[greenhorn520]

I am a student trying to learn. I may be entering the trade very soon. I just read about heat pump metering devices and it sounds like most of them use a check valve, although it did say refrigerant can flow either way through a capillary tube. This is the unit in the place I live.

[karsthuntr]

What you have is a piston coil. A check valve would be on a system with a TXV, not all TXV systems have check valves.

[Pascone10]

I am a student trying to learn. I may be entering the trade very soon. I just read about heat pump metering devices and it sounds like most of them use a check valve, although it did say refrigerant can flow either way through a capillary tube. This is the unit in the place I live.

Where were you reading this at? A lot of the textbooks show piping schematics.
If there was a check valve you would see a bypass line around the MD.
The Flowrater is not restricting flow in the other direction. Again not going into much detail.

Its a good trade. Very rewarding if you ask me!

[greenhorn520]

I'm reading this in my 1200 page text book, it's hard to interpret every detail I read, some times things need to be explained in more than one way. And yes I realize there would be a bypass line for the check valve. BTW, the book also shows check valves with the the capillary tube set-up, not just with the TXV. It does show the piston coil/flowrater not with check valve, but I don't remember it referring to that device by those names.

[hvacguru69]

Its metering only in one direction, it bypasses around piston in the holder during heating

[greenhorn520]

I've rented two places with heat pumps, one was a package unit (not very old), and the other an old split system. They seem to be pieces of crap. The package unit would go into defrost mode too often and for too long. The one I have now has an intermittent problem where the compressor doesn't run, it just circulates what ever air is in the house(heating and cooling mode). In both experiences techs looked at them many times and never fixed them right. I don't think I like heat pumps.

[hvacguru69]

I've rented two places with heat pumps, one was a package unit (not very old), and the other an old split system. They seem to be pieces of crap. The package unit would go into defrost mode too often and for too long. The one I have now has an intermittent problem where the compressor doesn't run, it just circulates what ever air is in the house(heating and cooling mode). In both experiences techs looked at them many times and never fixed them right. I don't think I like heat pumps.

Sounds like to me you just live somewhere where it gets real cold and techs there dont work on heat pumps very often. Here in phoenix az, heat pumps are king, and they work great. You just need to find a tech that know his way around one.

[greenhorn520]

I live in Tucson actually.

[hvacguru69]

I live in Tucson actually.

In that case, you should find someone who can easily fix the problem

[greenhorn520]

That's what I thought, but apparently it's not that easy because my previous and current landlords have not been able to accomplish that.

[lynn comstock]

Its metering only in one direction, it bypasses around piston in the holder during heating

Exactly right.