Help design my new system please

[NiHaoMike]

Looks good. When assembling, the compressor and filter drier should be the last parts to get connected as they can be degraded by moisture.

You'll be better off with a reflector type light bulb as it's much cheaper. And even better off strapping on a few power resistors or going with the copper tubing idea.

This is the preferred type of power resistor:
Fileanotherm HS50 power resistor.jpg - Wikipedia, the free encyclopedia
(Don't buy any yet, we'll get to that when we plan out the electronics stuff!)

A R410a compressor is going to be especially heavy as it has to withstand a lot of pressure. My friend Brittany Benzaia told me an interesting story that back when she was doing HVAC service (mostly for the real world experience), she once had to replace a central A/C compressor (2.5 ton IIRC, but R22). When she brought the old compressor into the parts store to get a replacement, everyone stared like they never saw it happen before.

[buffalobillpatrick]

Check out these suckers!
13 Big Power Resistor | eBay

[buffalobillpatrick]

Is 1/2" ACR between TXV & evaporator big enough?

ROBINAIR 18560 VALVE CORE REMOVER any good?

BBP

[jeff5may]

Originally Posted by buffalobillpatrick

jeff5may, I expected a rebuttal?
If what I have researched is wrong, please let me know why.

My new Copeland compressor came, Is it filled with lead?

I have found some Packless VIBRATION ABSORBERs to connect to compressor. Good idea?

So this is list of components in order:

compressor -> vibration absorber -> 1/2" ACR -> high pressure cutout -> thermal switch cutout -> service port for line to gauge -> condenser 1/2" port (top) ->

condenser large port (bottom) -> 1/2" ACR -> SLHX -> 1/2" ACR ->
service valve -> service port for line to gauge ->
filter/dryer (outlet down) -> sight glass ->

2T R22 external bulb TXV -> 5/8" ACR -> service port for line to gauge ->

evaporator small port (bottom) -> evaporator large port (top) ->
3/4" ACR -> SLHX -> 3/4" ACR ->

large accumulator -> service valve -> service port for line to gauge ->
low pressure cutout -> sight glass -> vibration absorber -> compressor

So I have 4 pressure gauges on REFRIGERTION CHARGING HOSE 1/4"

& 2X service valves for vacuuming & charging.

I will have a gauge to monitor compressor current & 6 temperature sensors monitored by same Arduino that controls system.

Please critique?

BBP

I went down the same road as you are on now. The water is murky in this realm, to say the least. Since you are building a water source, water sink heat pump, you will be able to directly measure your BTU values. Mine was air source, air sink. I found a happy point at about 15 degF of superheat at the txv sensing bulb. Advice: get a couple of sight glasses (I didn't and regret it).

I played around with suction line HX's and found they work best in heating mode when it's cold outside. This is when the added superheat can help overcome the large delta T between indoors and outdoors. Considering their expense and complexity, I opted to boost performance by oversizing the outdoor HX. The only time I would use one is if I needed a suction accumulator. I would install one with a built in HX.

[Mikesolar]

I'm having a tough time understanding why you feel the need for a crankcase heater. This unit is indoors. There should be no need for one. Am I missing something?

[NiHaoMike]

It's good practice when using R290 or a refrigerant that is mostly R290. R290 has a high tendency to dissolve into the oil. Great for oil return, not so good for lubrication on startup.

The type of power resistor you linked won't work for this application. The metal cased type I linked is ideal, but the more common ceramic blocks will also work.

!/2" is good enough for the TXV outlet.

[buffalobillpatrick]

Topic pot heater. see I'm picking up on your slang.

4 Dale Ceramic Power Wire Wound Resistor 25 Ohm 40 Watt HL 35 09Z USA Seller | eBay

8x in series would = 72W on 120vac & with the holes in tabs would allow easy conection around compressor. Would have to add electrical safety shield.

BBP

[NiHaoMike]

Those might work, but the terminals on the sides coated with only a thin layer of paint are easy to short out.

This is the kind of ceramic resistor I'm thinking of:
http://www.nteinc.com/resistor_web/pdf/twentyfive.pdf
If you can get this kind of metal cased resistor, even better:
http://www.nteinc.com/resistor_web/pdf/25w_50w_alum.pdf
Actually plan on sizing them for 240V, split into two groups that are each wired across each pole of the contactor. Add a SSR in series with one group to control the exact power.

[AC_Hacker]

Originally Posted by NiHaoMike

It's good practice when using R290 or a refrigerant that is mostly R290. R290 has a high tendency to dissolve into the oil. Great for oil return, not so good for lubrication on startup.

I share Mikesolar's disbelief.

Is there anywhere else on the planet where using power resistors to heat up the crankcase of a compressor, that contains some percentage quantity of R290, that is already at room temperature, is actually required?

This seems too me to be a kludge looking for a home.


-AC

[buffalobillpatrick]

The Copeland/Emerson instructions entire back page is devoted to heaters, 22 different models are listed for their many different compressors.

My compressor calls for PN 018-0094-00 40W 240V wholesale $13.06 but can't find any for sale yet.

So how many installers order them is unknown to me.

BBP