Heatcraft Condensing unit for air conditioning?

[ammoniadog]

I have a job coming up where my boss wants to hook a walk-in-cooler-type condensing unit to a Bryant air handler with a 5 ton A-coil. This is for a place that might need air conditioning in the winter when it's cold outside. Our company has rigged up these systems in the past with good results.

The only issue is the last ones we did were R22, so that made everything match up nice and easy. This time, the condensing unit will be setup for R404A, while the air handler will come with a R410A expansion valve.

I've got 2 options to make it work. I need some help deciding which direction to go.

Option 1... Install R404A TXV made for medium temperature, charge with R404A.
Option 2... Install R22 TXV made for high temperature, charge with R22 substitute.

I'm kind of leaning towards using R404A with a R404A expansion valve. I just wasn't sure about using a medium temperature R404A txv for air conditioning. Would it be possible to custom make a txv that's matched up for high temperature and R404A? Is there even a difference between medium and high temperature expansion valves?

Would there be any issues with pumping a R22 substitute through a condensing unit made for R404A? I'm guessing the headmaster would still work good enough and the compressor really shouldn't care either way, but I guess I'm not sure.

I guess another option would be to get a condensing unit that's made for R449A, but I think the condensing unit has already been ordered and is waiting for us at United Refrigeration. Should I tell my boss to change the order and go that route instead (with a R22 txv to go with it)?

Which way should I go?

[pecmsg]

Standard condensing unit with a speed drive on the condenser fan.

[pecmsg]

I’ll add
Make it a pump down.

[Snapperhead]

I have a job coming up where my boss wants to hook a walk-in-cooler-type condensing unit to a Bryant air handler with a 5 ton A-coil. This is for a place that might need air conditioning in the winter when it's cold outside. Our company has rigged up these systems in the past with good results.

Ha .... thats pretty neat

404 TXV for sure

[BBeerme]

I'm more with Pecmsg on this one. Running A/C when it is cold outside is nothing new. Some units that are made to be shipped anywhere also have a time delay to bypass the low pressure switch for something like one minute to allow some pressure to be built up.

The most economical, if you've got the room or space for ducting would be to have an economizer.

[R600a]

If you use 404a in an air conditioning application I want to hear all about it.
The thread I started on the subject kind of died because it seems there's not much information on it.

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[Snapperhead]

Im not sure how long R22 substitutes will be around ... Well im not sure about 404 being around either , but probly longer than the 22 stuff

[ammoniadog]

I've seen a fair amount of new walk-in's coming set up for R448A/R449A (R22 substitutes). Who the hell knows what the flavor of the future will be, but hopefully at least one of those choices will be around for a while.

My boss is telling me to go with 404A, so I guess that's what it will be, and yes it will be a pumpdown system, with the Y from the thermostat opening and closing a 24V solenoid.

Looks like this might be a couple of weeks out before we get started on it. I'll update on how it went after it's done.

[pecmsg]

I’m not sure but I feel your going to have a High Compression ratio with 404!
You just might need a crankcase pressure regulator.

[ammoniadog]

I’m not sure but I feel your going to have a High Compression ratio with 404!
You just might need a crankcase pressure regulator.

Nope, it would be a lower than normal compression ratio. The part about a CPR being useful might be a valid point due to the higher than normal suction pressure, but my hope is that evaporator temperature/suction pressure between an air conditioner and a walk in refrigerator are close enough so that it might not be an issue.

[Snapperhead]

walkin evaps are 20 deg

[ammoniadog]

walkin evaps are 20 deg

Yeah, and air conditioner evaps are around 30°. Doesn't seem like that big of a difference to me.

My thought is that maybe the lower compression ratio can make up for the higher return gas temperature and denser refrigerant.

[2sac]

walkin evaps are 20 deg

Wine and flower coolers are running 35-45* coils. Sporlan makes a R404a powerhead for high temp. Thermostatic charge is SCP115. You would need to call Sporlan to get the exact configuration of the valve to order because I'm just about 100% sure it's not "off the shelf" anywhere. Just an FYI, Sporlan's lead times have increased from their normal 3 weeks to 5+ week lead times because of covid supply chain issues.

[ammoniadog]

Thanks 2sac. I just skimmed thru a Sporlan PDF that I found, and it seems that their "commercial" valves (what most people probably consider "medium temperature") are rated from 50°F to -10°F, so I think I should be fine with a normal walk-in cooler txv. I will check into the SCP115 if I can find it though.

[icemeister]

Heatcraft rates all of their medium temperature scroll units up to 40°F evaporator temperature and Copeland rates the ZS scroll compressor up to 45°F evap temp for R404A. I see no problem using them for an R404A air conditioning application.

The Sporlan "C" charge will work fine in the 40-45°F range as its performance is fairly flat over a very wide range from HT, MT and LT.

[R600a]

You all are making me want to put in a refrigeration condensing unit on my house just so that I can call out another company to service it and sit back and watch the entertainment.

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[jbhenergy]

Why not a standard condenser with an ICM head pressure control. I have a couple installed in places that need ac in winter and they seem to work well. Even has a bypass to allow heat pump operation of wanted to go that route.


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[ammoniadog]

Why not a standard condenser with an ICM head pressure control. I have a couple installed in places that need ac in winter and they seem to work well. Even has a bypass to allow heat pump operation of wanted to go that route.


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Because it's my bosses idea, and because refrigeration units are better!

Yeah, the receiver and headmaster might be overkill, but they do get the job done!

And I guess the fact that it won't need thermostat wire ran to it will be a nice little bonus!

[pecmsg]

Because it's my bosses idea, and because refrigeration units are better!

That’s the most important reason.

[icy78]

The flip side of this topic is the number of r22 AC condensers I see on WIC.
Some have been running for 20 years. Theres a lot around here.

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