OT: R-22 in heat pump

"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message


Probably not for the backyard variety of propane.
--IIRC there is way too much moisture in it which would be fairly difficult for a non-tech-type to deal with, making "gas and go" from a barbeque bottle a very risky proposition for the average diy homeowner.
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Interestingly enough, the pre-packaged Coleman propane in the 14oz bottles is quite dry and pure. It has more mercaptans in it than is desirable (they can settle out and "gunk up" machines), but it's been used by amateurs quite a bit for recharging R-22 machines. Not recommended for capillary tube units for the reason of the goo.
I think they scrupulously dry it because the steel bottles are not corrosion-treated on the inside. Any moisture present would tend to acidify (like it does in an AC), and attack the bottles from the inside- out.
LLoyd
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message

Thanks, Lloyd
--



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Lloyd E. Sponenburgh <lloydspinsidemindspring.com> wrote:

or maybe new connectors on propane tanks?
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Yeah, like non-condensibles in the system.
High high, and high low, too, and no cooly.
LLoyd
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message

hehehe
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On Apr 14, 4:43am, "Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote:

LLoyd,
I went to HVAC school. Even this does not make me an expert. But let us for a moment think about a home with the furnace in the basement, the condensing unit sitting on a pad outside the home. If a refrigerant leak was to occur in the evaporator located inside the duct there is no provision to detect this prior to the ignightor being engaged. In this example you would have an air fuel mix inside the duct and you would have a big boom.
I did a quick google search and found R22 in 30lb. cans @ $226, that is a cost of $7.54 per lb. Assuming that Tom needs 5lbs that is $37.67. If the HVAC guy charges double that is about $75.
Now I am not sure what the R290 will cost but unless someone is going to pay Tom to use it the most he could save is the $75. On the other hand reading from the Tecumseh guidelines he might need a new compressor they say:
"Compressor selection: Tecumseh offers selected compressors for use with R600a and R290. These compressors have the letter M as the designator for R600a and the letter U as the designator for R290, e.g., AZ_1335M_and AE_9415U_. It will be necessary to test each compressor selection in the applications to determine its suitability, since system operating conditions vary greatly from one application to another."
Assuming that sitting right next to that evaporator is an expansion valve, that might need to be changed also. Tecumseh says:
"Expansion valve selection: The expansion valve manufacturers have designed product specifically for use with R600a and R290. Consult them for their recommendations."
Tecumseh further says:
"Since special safety considerations must be applied in the design of equipment using hydrocarbon refrigerants, such as R600a and R290, Tecumseh does not approve of, endorse, nor recommend retrofitting existing systems with R600a and R290."
"Special safety considerations". All to save $75 worth of R22? If I understand you correctly, that this is a good thing for Tom to consider. Have you checked to see if Tom's compressor is compatable with propane? His expansion valve?
You are entitled to your opinion, I do not claim to be an expert on retrofitting a home AC system designed to run on R22 to R290. I suspect however that the engineers at Tecumseh probably know their stuff.
So while I admit that my level of training does not make me an "expert", I think that Tom would be better off paying for a service call and having the AC guy fix his leak and charge up his system.
You might also read this: http://www.dailymail.co.uk/news/article-1210334/Alert-new-wave-exploding-fridges-caused-environmentally-friendly-coolant.html
Now consider the amount of propane refrigerant in a refrigerator vs. the amount in a home AC system. All to save $75?
So perhaps I am a blowhard, but I would prefer not to risk my home or Tom's home just to save a few bucks on gas.
Roger Shoaf
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Sure... I agree with that completely, but THAT wasn't your objection. Your technical objections have all been weighed by the _real_ experts (neither you nor me), and they have decided that R-290 probably will be accepted for domestic HVAC equipment within a few years.
Is it worth his cost to do it himself? Might be... Tecumseh has to justify selling new Ex-valves, compressors, and reversing valves somehow. Designing them _just_so_, so they're _optimized_ with either 600a or 290 (can't be both, they have different curves) will make them money.
But the truth is, propane works just fine in most R-22 systems, with the exception that mercaptan loading must be low in capillary tube systems, and the efficiency of an expansion valve system may drop off 3-5%.
Had you originally argued that it wasn't worth his effort for the price, you'd have gotten no argument -- but you started objecting on technical grounds.
LLoyd
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"Lloyd E. Sponenburgh" <lloydspinsidemindspring.com> wrote in message

I appreciate all the ideas and wisdom! I hope it just needs a few pounds of R-22 and that if I tighten the Schrader valves and replace the caps with new O-ring type, I hope I get a few more years out of this unit. The new higher efficiency units won't pay for themselves for at least 10 years. Maybe by then they will have better technology available and cheaper.
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Good advice, I've got a gallon of purple stuff coil cleaner that you mix with water and spray it on with a pump-up garden sprayer. It makes the AL look bright and shiny. What's in that stuff? I assume it's some kind of acid.
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Lye.
Make sure you rinse it squeeky-clean after the stuff has done its deed, or it will continue to - um - "clean" the aluminum fins until they're so clean you can't even see them anymore! <G>
LLoyd
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Purple stuff has caustic in it, caustic soda *eats* aluminum. The opposite of an acid, it's a powerful base. Good for making soap out of organic greases and oils so they can be rinsed off. Not so hot for metals that react with it. And aluminum reacts with just about anything, acid OR base. Get it well rinsed off afterwards.
Stan
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My bud said most leaks on that type of system will be cured by tightening the Schrader valves and replace the caps with new O-ring type. Makes sense to me.
If I have the slightest problem, I'll call a pro. My bud's bud loaned me a 30 pounder in trade for some brushes and he said to call if I need him. How cool to have friends!
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Tom Gardner wrote:

Your bud said to tighten the valve cores, right? With a little slotted tool that's made to fit inside the end of the valve and fit over the core, right? You're not going to put a wrench on the outside of the valve and turn the whole thing, are you?
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It's those little valves like in a tire stem and the caps that fit over them. It makes sense that the o-rings don't last forever and older caps don't have o-rings.
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