TX valve with Amana/Goodman heat pump and ARI ratings

[spearingusenet]

I am going to be ripping out my oil furnace and installing a heat pump and am about to pull the trigger on an Amana (Goodman) 3.5 ton and variable speed AHU. From what I can tell, they come with a flowrater instead of a TX valve. Three items I hope someone can help with:

1. Can someone confirm that the "flowrater" is not a TX valve and is just an orifice arrangement in place of the TX valve? What do they do?

1. A majority of the Amana ARI ratings say " + TXV " in the AHU column. I assume this means that a TX valve was installed in the AHU for the test. Why would they do this when the standard unit comes with a "flowrater"? Will it improve both heating and cooling performance?

2. If I go with a unit with a factory flowrater, should I insist that they install a TX? I would use the unit 93% of the time for heat. What does the TX improve and how? Any downsides to a TX (moving parts, longevity, etc.)?

Thanks for any help!

S

[Bubba]

Yes. It meters refrigerant

They just get bored so they test it the opposite way the rating says

Yes! Insist that they use a flow rater AND a TXV. This is the only way to get peak efficiency and keep your compressor running for a lifetime. Bubba

[Stormin Mormon]

1. Can someone confirm that the "flowrater" is not a TX valve and is just an orifice arrangement in place of the TX valve? What do they do? CY: I'll confirm that. Orifice is a tiny hole which allows the freon to expand. A TXV is an adjustable tiny hole. It adjusts based on the temperature of the suction line.

1. A majority of the Amana ARI ratings say " + TXV " in the AHU column. I assume this means that a TX valve was installed in the AHU for the test. CY: That's possible. I didn't read the article.

Why would they do this when the standard unit comes with a "flowrater"? CY: Cause it's more efficient.

Will it improve both heating and cooling performance? CY: Only cooling. Improves cooling performance.

1. If I go with a unit with a factory flowrater, should I insist that they install a TX? I would use the unit 93% of the time for heat. CY: For occasional use, might not be worth it.

What does the TX improve and how? CY: Varies the flow of freon through the evaporator coil. Based on the demands of the system.

Any downsides to a TX (moving parts, longevity, etc.)? CY: They tend to be dependable. They clog fairly easy, so the installer should put in a filter drier right before the TXV.

Thanks for any help! CY: Glad to.

S

[Murdentech]

Flowrater is a standard piston, or fixed orifice. TXV is theral expansion valve. It adjusts the refrigerant flow based on system load and increases efficiency at less than maximum load.

The TXV at the indoor unit will improve latent heat (moisture) removal in the cooling mode. The indoor metering device has no function in heating mode. The metering device for heating mode is located in the outdoor section of the heat pump. Notice that heating performance is not rated in SEER, rather it is rated in COP (Coefficient of performance). The outdoor metering device is installed at the factory (TXV or fixed) and is not field changeable.

A TXV can improve cooling performance. Some ARI rating require the TXV to meet the standard. There is a downside to a TXV. It is more difficult to adjust the charge. The TXV can become stuck and cause performance issues. Goodman has had problems with their TXVs in some applications. The TXV costs more to install.

[gofish]

Insist on an evaporator coil with a factory installed txv, and NOT the flowrater crap. Then insist on ARI certified matched coils. Who's money are we spending anyway?

[Moe Jones]

Just think that the metering device is like a carburetor on your car. The better the carburetor the better the performance.

[udarrell]

Where do you live? Sounds like you need a furnace, not just a heatpump.

If it gets cold at night & you use the A/C the that day, then it needs a crankcase heater on the compressor! In cooler climates for many reasons, a TXV is a must! Read & learn.

Oil furnaces can result in airflow problems with the addition of A/C or heatpumps.

[udarrell]

Where do you live? Sounds like you need a furnace, not just a heatpump.

If it gets cold at night & you use the A/C the that day, then it needs a crankcase heater on the compressor! In cooler climates for many reasons, a TXV is a must! Read & learn.

Oil furnaces can result in airflow problems with the addition of A/C or heatpumps.

- udarrell

[Bubba]

Jeff, Just curious. I havent seen the problem with a TXV being more difficult to adjust the charge?in fact, seems a lot easier. Quite frankly, with 13 SEER here now, I think the piston flow rater crap needs to disappear. What problems have you found with adjusting the charge on a TXV? Bubba :-)

[spearingusenet]

I live on southern Vancouver island and there are very few days below zero here. Our house is close to the ocean (~300 ft) which further moderates temperatures on colder days and lots of nice breezes to cool the house. The third reason that I am not putting the furnace in is that we have an air tight wood stove that we like to use. We really like the heat it gives off.

Does anyone know if any of or which of the Amana or Goodman outdoor units units have a factory TXV? I don't want this to turn into a brand discussion but if the Amanas don't do this at all then is there anyone else who makes a lower cost unit with tx in the outdoor unit?

Also, should I insist that they insulate both the supply and return outside the house?

s.

[Noon-Air]

If you want it to work, use Goodman or Amana

If you want it to work well, use Trane or Rheem

[Murdentech]

I should have said... can be more difficult to diagnose a charge / low charge condition.... We were on a job where the house would not dehumidify adequately and it seemed the TXV was not responding properly. Pressures were fine but the coil would not sufficiently flood. The house would cool fine, but the darn unit just wouldn't pull the humidity. Finally took the bulb loose, did the ice water / hot water trick and let it hang. After that the coil flooded nicely and was nice and cold all the way across.

Had another job on a 7.5 ton commercial heat pump, where the little pinion rods in the valve were stuck solid at the indoor coil.... took the TXV apart and had to pull the rods out with a channel lock... replaced the TXV head and rods and the unit ran like "40 going north".... that unit had a previous compressor replacement and some other hack work done to it over the years.

I hate following up someone else's sloppy work !! I have enough of a time fixing my own messes ;-)

[Murdentech]

Bullshit... beside he said he doesn't want a brand war... you have to go there...

[spearingusenet]

As I suggested, I would rather not have a brand discussion without going into specific details on specific models here. We will all have our points of view and I am trying to form mine based on appropriate and accurate information. Thanks.

S.

[Noon-Air]

Plenty of "appropriate and accurate information" on the manufacturers web sites, the ARI web site, Consumer Reports, DOE, EPA, etc. Can't get into what units come with what "accessories" installed at the factory without getting into the brands, and specific models. You seem bent on some of the cheapest POS equipment, thats fine. You are gonna get what you pay for.... likewise, you are *not* going to get what you don't pay for. You want the information, go find it.

[zero]

Then hire somebody to provide you with accurate information. You pay them>they f*ck up> you have recourse.

If you cannot comprehend and apply the free info given so far, you should hire a consultant.

No one gives a shit what you would "rather not have". Try

or the HVAC-talk thing or something else.

-zero

[Dido]

What in the world is "FLOWRATER" and who is using this word Dido

[Bob_Loblaw]

[e-mail] wrote

"Dido" wrote

Do us all a favour and pull the trigger on Dido too.

[Bubba]

"Ditto" Bubba