Please help with possible piston orifice issue. Thanks.

[gagecalman]

Hi all,
Sorry for the long post. Thanks for reading and any help.
I'm looking for some educational help with a possible piston orifice issue.
I have a Nordyne 18K split system installed in 2012 that is cooling the upstairs of my cape cod.
Air handler is a B6BMM024K-A. Condenser is a S4BD-018KA. The micro channel evaporator coil sprung a bad leak and had to be replaced.
New coil is a Nordyne REPLCOIL01M.
I had the guy that originally installed it do the work. He's a friend and has his own HVAC company.
The new coil has a 067 piston already installed, The old coil had a 055 piston installed.
There isn't anything on the condenser or in the manual stating what it should be so he went with the 067. He thought maybe they changed the coil design.
He added the 410a by the weight stated on the condenser, looked at the pressures and said looks good.
He did not check SH or SC. He's usually better than that.
I noticed the suction line sweating a lot more than normal so I checked it out myself. It was 47°.
I checked everything else and found that the SH and SC are both 2°.
So before I give him a call I'm just trying to understand if it's the piston or could it be overcharged.
Outdoor 86°. Indoor 74°. Wet-bulb 60°.
Thanks for any info.

 

[Jim greengo]

I'd use the piston from old coil if you still have it,or find a replacement.

 

[fitter30]

From what i could find the new coil orifice .067 is 2.5 ton. Have to remember that manufacturers by changing airflow and orifice size they can change btu ratings of the system by 3-4k btu's. That label on the condenser is how many lbs of refrigerant it was shipped out with. System could have 15 to 50' of lines. Your service guy needs to call talk with the factory tech to get the correct size orifice. Factory tech if be can't pull it up a email or phone call to the factory. Sc and sh is for txv. Total superheat heat for cap tube or orifice. Measure the indoor WB (wet bulb) temperature and the outdoor DB (Dry Bulb temperature. Input these temperatures in a superheat chart, calculation, app, or digital manifold set to determine the target superheat for that moment in time. With txv sh should be 10-12° sc 10°

 

[PoorUB]

My information shows a #55 for 18,000 BTU, 67 for 30,000.

 

[gagecalman]

My information shows a #55 for 18,000 BTU, 67 for 30,000.

Any chance you could post or send that info?
I can't find anything in the manual.
Thanks!

 

[PoorUB]

I would have to search again but Google 1 1/2 Goodman metering device size.
Do you have the install instructions for the condensing unit? It should show meting device sizes.
The info for the coil might not say much as the coil may be good for several condensing unit sizes.

 

[gagecalman]

Nothing in the manual. It's a Nordyne so I don't know if that makes any difference.

 

[karoc]

Is it cooling, temp going into your return and air temp coming out grill should be around 15-18 DT.
I could be wrong but system with flowrater charge by SC and not SH, but my memory may have let me down

 

[gagecalman]

It cools but with the SH so low I'm concerned about liquid going into compressor.
Charge by SH with a piston. SC with a TXV.

 

[justinjoyal]

Try the .055 piston.

If everything else is right, including the charge (which has been weighted in so it must be), it seems like the current piston is oversized.

 

[PoorUB]

Nothing in the manual. It's a Nordyne so I don't know if that makes any difference.

I don't know why I was thinking Goodman. but the orifice sizes are generally the same from one brand to another. Either way the 67 orifice is too large. No doubt in my mind! I would not hesitate to put the 55 in it.

 

[gagecalman]

He said he contacted tech support and they told him the correct piston should be a 048 for the 18K condenser and that coil.
He's getting one and we will see. Hope it's not too small. SH seemed to be fine for 11 years with the 055.