r12 walk in to 134a

[Poodle Head Mikey]

PHM
------

Rofl...I love it. But 407a is a r22 replacement and he would have to change txv which he has no access to.
Call

[MontanaJon]

My bad. 417a. I mistyped. ;-)

[Snapperhead]

I don't see a lot of 404a cap tube systems!

Victor freezers use double line cap tubes , 404 , twice the fun

[Poodle Head Mikey]

And, as I said before; R-417 is less expensive.

PHM
-------

My bad. 417a. I mistyped. ;-)

[thermofridge]

What is the price of 420A? Thats what I would dump in there. Simply because I have a few drums on hand.

[thermofridge]

$288.86 is my current price.

[MontanaJon]

PHM if your raise was about the price of refrigerant than i fold and the pot is yours.. But from what i have briefly read is that r417 is a R22 replacement and the gentleman didn't want to have to do a lengthy conversion. This is why i recommend the R416a. If he converts to anything other than a R12 replacement then he will have to clean the whole system up, replace Txv (which he said he would have to drop the evap) and replace the piston in the distributor and most likely the compressor.

[lytning]

Or he could just replace it with 409 and be done with it. Right not cheap, but I have always had good luck with it and will continue to use it as long as I can. No propane in it.

PHM if your raise was about the price of refrigerant than i fold and the pot is yours.. But from what i have briefly read is that r417 is a R22 replacement and the gentleman didn't want to have to do a lengthy conversion. This is why i recommend the R416a. If he converts to anything other than a R12 replacement then he will have to clean the whole system up, replace Txv (which he said he would have to drop the evap) and replace the piston in the distributor and most likely the compressor.

[MontanaJon]

Lytning the o.p. stated that 409 was too expensive for him. 409 is a good replacement and have nothing against it. Was giving my 2 cents.

[Poodle Head Mikey]

PHM
-------

PHM if your raise was about the price of refrigerant than i fold and the pot is yours.. But from what i have briefly read is that r417 is a R22 replacement and the gentleman didn't want to have to do a lengthy conversion. This is why i recommend the R416a. If he converts to anything other than a R12 replacement then he will have to clean the whole system up, replace Txv (which he said he would have to drop the evap) and replace the piston in the distributor and most likely the compressor.

[lytning]

Ahh, I must be thinking of 416. Light green can?

[MontanaJon]

Yep

[MontanaJon]

PHM you are correct that R417C is Hot-Shot 2, a R12 drop-in.

[monkeyspanners]

If its short cycling because the compressor head valves are letting by and customers got no money, fit a check valve in the suction line just before the compressor and fit the LP switch before the check valve so it will still maintain the correct evaporator pressure. No need to change the refrigerant or fit solenoids, stats etc.

Sometimes you gotta do what you gotta do even if its not ideal.

[kklobas]

this sounds like a perfect bandaid idea. I like it. I reset controls as PHM suggested, went a little higher to compensate- i believe 40-20 psi, and it has been running a few days i assume or they would have called. I'll be back there tonight for a different cooler, and will check. this could be good though. It was actually cooling ok, just had suction rising to fast. thanks for another idea

[ammoniadog]

If its short cycling because the compressor head valves are letting by and customers got no money, fit a check valve in the suction line just before the compressor and fit the LP switch before the check valve so it will still maintain the correct evaporator pressure. No need to change the refrigerant or fit solenoids, stats etc.

I don't think a check valve will work, since you aren't trying to pump down the system. I don't think you ever diagnosed that the valves were actually not holding. If the valves are holding, and you add a check valve, it will still work exactly the same. It seems to me that the system is shutting off and the pressures might just be naturally rising because the condensing unit is in a warm place.

If you really want to, you could replace the low pressure control with a conventional thermostat. No need to cut the system open and add a pump down solenoid, just run the system like it is, but with a thermostat instead of the pressure control.

If you do this, it would probably be a good idea to also add a defrost timer to it. Another option might be to leave the l.p. control in there wired in series with the thermostat and set it so it will open up and act like a defrost control if the pressure gets too low.

Another option, is to go with the time delay relay as mentioned before, along with a contactor or something like this RIB relay (that is good for 20 amps) to control the compressor...
http://www.grainger.com/Grainger/wwg...rue&sst=subset

[Poodle Head Mikey]

You may be thinking of R-417A - which is a replacement for R-22 - comes in a light green cylinder.

But what I am trying to draw your attention to is R-417 - which is a drop-in for R-12 and the other medium pressure refrigerants. And it is presently available at lower costs than the other substitutes. Icor calls it: HotShot2

PHM
------

Ahh, I must be thinking of 416. Light green can?

[Poodle Head Mikey]

The more standard and less expensive repair option would be to install a constant cut-in thermostat sensing evaporator temperature to control the box temperature - use 37º or so and on each cycle the evap coil has to de-frost before the compressor will come back on. Much easier and less expensive than redesigning the whole machine.

Any dam fool can get complicated - it's Simplicity that is Genius. <g>

PHM
------

I don't think a check valve will work, since you aren't trying to pump down the system. I don't think you ever diagnosed that the valves were actually not holding. If the valves are holding, and you add a check valve, it will still work exactly the same. It seems to me that the system is shutting off and the pressures might just be naturally rising because the condensing unit is in a warm place.

If you really want to, you could replace the low pressure control with a conventional thermostat. No need to cut the system open and add a pump down solenoid, just run the system like it is, but with a thermostat instead of the pressure control.

If you do this, it would probably be a good idea to also add a defrost timer to it. Another option might be to leave the l.p. control in there wired in series with the thermostat and set it so it will open up and act like a defrost control if the pressure gets too low.

Another option, is to go with the time delay relay as mentioned before, along with a contactor or something like this RIB relay (that is good for 20 amps) to control the compressor...
http://www.grainger.com/Grainger/wwg...rue&sst=subset

[MontanaJon]

I was thinking of 417a because you only said 417.

[kklobas]

Thanks for all the replays.
As of now i took PHM's suggestion, set a 20 psi differential, and tonight i was back there. Still cooling. Amazing- this is a plywood/2x4 box. Nothing but a fan cycle and lp control for controls...
The t-stat idea- if i understand right is take the wire out of lp control, run through a stat like a 16901 and back, so both t-stat and lp have to close to run compressor, but if either opens it will shut off? I like the idea. It is funny the effort put into something like a plywood beer walk in. But hey-it's essential to the bar right?.......