once again mp39/401a is the perfect drop in for r-12

[Airmechanical]

did another r-12 compressor changeout today, mechanical breakdown (busted crank) today for a

10 door beer cooler at at a convienence store, the customer had a spare r-12 compressor,

changed it out, slammed 25 lbs of mp39 in, filled sight glass, another done deal, did not

change oil, did not change expansion valves, that puppy was purrin like a

kitten, pressures were 38/190 cooler temp was 38 degrees at completion!

this post is just another thumbs up for this drop in refrigerant!:)



.

[k-fridge]

No doubt, MP-39 is one of the best replacements for R-12 in medium temp applications. But there is no such thing as a drop in for R-12, MP-39 is classified as a near drop in. The existing TXVs should be fine as long as they are in good shape, but an adjustment may be required. AB is the preferred oil for it, it's recommended that in a mineral oil system at least half the oil be changed to AB.

[shaun66]

i use MP39 exclusively for R12 replacemnt, must have 20 racks running MP 39, but i always change oil to AB and check TEV'S and adjust superheats as needed

[fix_it_dude]

hey dudes:
have you guys use 409 as a drop-in for r-12 ?

[the mojo]

hey dudes:
have you guys use 409 as a drop-in for r-12 ?

Yes, some folks use MP-39 R-401A with great success. Suva 409A is a very good choice for R-12 replacement as a Medium temp application. Just watch your S.H.

[fix_it_dude]

Thanks mojo dude

i also have use 408a as replacement for r502 and it works very well.

thanks again dude

[heatermanbob]

sadly our general manager has it in his head that 416A is the best R-12 replacement and thats what we are required to use.. sure makes it a pain when there are multiple evaps. I like MP39 and 409A

[TGoodrich]

I've used 409a, 401a, 401b, and 414b for retrofitting R-12 sytems. They all work fine unless you have a system that is marginal. I mean if the compressor is on the verge of tripping the overload with R-12 for any reason, one of the blends will put it over the edge. I stock 414b(HotShot) in the trucks. It works well in 134a systems too. Keeps the inventory down!

[cg2]

did another r-12 compressor changeout today, mechanical breakdown (busted crank) today for a

10 door beer cooler at at a convienence store, the customer had a spare r-12 compressor,

changed it out, slammed 25 lbs of mp39 in, filled sight glass, another done deal, did not

change oil, did not change expansion valves, that puppy was purrin like a

kitten, pressures were 38/190 cooler temp was 38 degrees at completion!

this post is just another thumbs up for this drop in refrigerant!:)






.

What does that 190 head do to your compressor current draw?

[Airmechanical]

What does that 190 head do to your compressor current draw?


very good question!

it ran right at R.L.A. at start up

then once she cooled down to operating temp it was well within specs!

you must have done this once before :)



.

[300 Win Mag]

I like the Hotshot 414B- No oil changes, use less per pound than R-12 also. Aslo works for 134A.

[icehouse]

I like the Hotshot 414B- No oil changes, use less per pound than R-12 also. Aslo works for 134A.:p Last condensing unit change out had nothing but trouble with Hot-Shot", and I use to swear by it, now I swear at it (headpressure problems).Replaced with MP39 and no more problems.

[270wsm]

What king of head pressure problems you having with it? I have used it for over a year now with no known problems.

[k-fridge]

What does that 190 head do to your compressor current draw?
This is a good question. Most techs seem to be of the opinion that higher head pressure equals higher current draw. This is not necessarily so. We all know that most of the blends run slightly higher head than R-12 did, but that in itself is not what determines compressor load. In the early days of R-12 phase outs I did before and after baseline data comparisons and it was common to see 20-40 psi higher head at times but current draw the same or even lower. I think the AB oil change outs in some of the compressors contributed to lowering the current draw also.

You should always check the current draw when doing these conversions, but typically if you get the other factors in line the amps won't be a problem.

[icehouse]

What king of head pressure problems you having with it? I have used it for over a year now with no known problems.around 220#, unit kept dropping off on overload. Yes evacuated to 500 microns, three times. Recovered "Hot Shot" evacuated again to 500 microns recharged with MP39 and ran like a charm.

[270wsm]

Wow....I've never seen hot shot run over 150 psi. I guess its not the perfect refrigerant for every situation, but so far I have had great success with it. No HP problems at all.

[300 Win Mag]

Did you have a full sightglass of hotshot when you charged the unit?

[icehouse]

Did you have a full sightglass of hotshot when you charged the unit?
:p Sight glas is not the proper way to charge. Charged by sub-cooling unit ran about 30 minutes, then head pressure started climbing then unit cycled off on overload. Compressor got hot as h*ll. Recovered "Hot Shot" and evacuated and recharged with MP-39 ran like a charm. Still running no problems. Believe me I was teaching when "Hot Shot" first came out and I highly recommended it. Only thing I can think of is that I got a bad batch. That happened with 409 one time. This was in a hospital lab so I would not take any chances since I had MP 39 back at the house.

[wannafreeze]

from National Refrigerants web site:
"
HCFC - R401A
A blend of R-22, R-152a, and R-124, intended for retrofitting R-12 refrigeration systems. The pressure and system capacity match R-12 when the blend is running in a 10F to 20F evaporator, and there is typically an 8F temperature glide in the evaporator. Applications: direct expansion refrigeration and air conditioning systems designed for R-12 or R-500; good success in any size system, minor adjustment of controls needed. Discharge pressure increases compared to R-12, also slight increase in discharge temperature, however the increases are not as severe as some other retrofit blends. There is a drop in capacity at lower temperatures. R-152a content, an HFC, hurts the miscibility with mineral oil. It is recommended to change some of the oil to alkylbenzene unless the system is small and running at higher evaporator temperatures.

HCFC - R409A
A blend of R-22, R-142b, and R-124, intended for retrofitting R-12 refrigeration systems. The pressure and system capacity match R-12 when the blend is running in a 10F to 20F evaporator, and there is typically 13F temperature glide in the evaporator. Applications: direct expansion refrigeration and air conditioning systems designed for R-12 or R-500; good success in any size system, minor adjustment of controls needed. Discharge pressure and temperature increases compared to R-12, which may be a problem in
very hot ambient conditions. Capacity holds well into lower application temperatures (-30F). R-409A mixes well with mineral oil down to 0F. As a result it may not be necessary to change oil in systems which do not run colder than 0F in the evaporator (below that alkylbenzene should replace some mineral oil
"
I might convert to MP 39 after this..

[Yuma]

Out in the warm areas I have found that R-420 (which was once RB-276) works better than R-401 or R-409 for the high head issues...
Have changed out a number of refers and POUs without any problems.


Yuma,

[300 Win Mag]

:p Sight glas is not the proper way to charge. Charged by sub-cooling unit ran about 30 minutes, then head pressure started climbing then unit cycled off on overload. Compressor got hot as h*ll. Recovered "Hot Shot" and evacuated and recharged with MP-39 ran like a charm. Still running no problems. Believe me I was teaching when "Hot Shot" first came out and I highly recommended it. Only thing I can think of is that I got a bad batch. That happened with 409 one time. This was in a hospital lab so I would not take any chances since I had MP 39 back at the house.

That is weird, never had that problem, the reason I asked about the sightglass is a lot of tech's forget, fill the glass and then it is over.

[icehouse]

That is weird, never had that problem, the reason I asked about the sightglass is a lot of tech's forget, fill the glass and then it is over.:confused: :confused: Sight glass will show occasional bubble as unit will be 80% when properly charged. You also have a mixture of gas and liquid with blends.

[k-fridge]

:confused: :confused: Sight glass will show occasional bubble as unit will be 80% when properly charged. You also have a mixture of gas and liquid with blends.
Here we go again. :p The refrigerant manufacturers caused quite a myth with their poor choice of words.

The 80% rule of thumb is because the blends weigh less than R-12 and we charge by weight these days, hence the same volume will be lighter.

A TXV needs a full column of liquid. In a TXV system with a receiver you should fill the site glass. Then of course, you should add for Headmaster is so equipped and check vitals.

[icehouse]

Here we go again. :p The refrigerant manufacturers caused quite a myth with their poor choice of words.

The 80% rule of thumb is because the blends weigh less than R-12 and we charge by weight these days, hence the same volume will be lighter.

A TXV needs a full column of liquid. In a TXV system with a receiver you should fill the site glass. Then of course, you should add for Headmaster is so equipped and check vitals.From Icor http://www.icorinternational.com/html/hotshot/pdf/PT_CHARGING_GUIDELINEs.pdf also http://www.refrigerants.dupont.com/Suva/en_US/pdf/h71061.pdf

[k-fridge]

From Icor http://www.icorinternational.com/html/hotshot/pdf/PT_CHARGING_GUIDELINEs.pdf also http://www.refrigerants.dupont.com/Suva/en_US/pdf/h71061.pdf
I'm not disputing the 80-90% rule of thumb, but that doesn't mean you can't fill the site glass.

Charge a system to a full glass with R-12, then recover and weigh it. Charge the same system with Hotsnot or 409, then recover and weigh it. The 409 or Hotsnot will weight approx 80% or what the R-12 weighed.

Question- How much does a drum of R-12 weigh?
Answer-30 lbs.

Question-How much does R-409 weigh in the same size can?
Answer-24 lbs.

80% of 30 =24

The 80% rule applies to cap tube or critical charge systems where the charge has to be weighed in.

In a system that is charged by the siteglass...you just clear the glass.:o Then you'll have approximately 80% of the weight of the original R-12 charge.

Hope this makes sense.

[icehouse]

I'm not disputing the 80-90% rule of thumb, but that doesn't mean you can't fill the site glass


Charge a system to a full glass with R-12, then recover and weigh it. Charge the same system with Hotsnot or 409, then recover and weigh it. The 409 or Hotsnot will weight approx 80% or what the R-12 weighed.

Question- How much does a drum of R-12 weigh?
Answer-30 lbs.

Question-How much does R-409 weigh in the same size can?
Answer-24 lbs.

80% of 30 =24

The 80% rule applies to cap tube or critical charge systems where the charge has to be weighed in.

In a system that is charged by the siteglass...you just clear the glass.:o Then you'll have approximately 80% of the weight of the original R-12 charge.

Hope this makes sense.:( What about fractionation occuring due to zeotropic mixture?

[icehouse]

Don’t clear the sight glass. Zeotropic blends will ‘flash' by nature. A clear glass usually indicates an overcharged system.From Icors web sight:confused:

[k-fridge]

:( What about fractionation occuring due to zeotropic mixture?
Refrigerant won't permanently fractionate inside a sealed system/container.

[k-fridge]

Don’t clear the sight glass. Zeotropic blends will ‘flash' by nature. A clear glass usually indicates an overcharged system.From Icors web sight:confused:
Show me where it says that exact statement. With all due respect, your statement is wrong. A TVX needs a solid supply of liquid to function properly, regardless of what refrigerant it's using.

On a TXV system with a receiver, how are you going to overcharge it by clearing the glass? On a typical walk in cooler you can add another several pounds after clearing the glass and it won't hurt, it just backs up into the receiver. On systems with very long runs or multiple evaps, even clearing t he site glass doesn't always insure a solid column of liquid at the TXV.

How about a system with a Headmaster. You have to clear the glass and then add for the condenser flooding. If you leave it short like you're suggesting you'll be getting a call from a pissed off customer the first cold day.

Let's clarify something here...the blends will sometimes have a cloudy appearance in the site glass due to their nature, that is not the same thing as bubbles.

I am aware of what the manufacturers have written concerning the blends. I'm also aware that it is terribly mis-interpreted. It's about weight folks, not volume.

[icehouse]

RIGHT HERE http://www.icorinternational.com/index.php?main_page=page&id=25&chapter=0:(

[k-fridge]

RIGHT HERE http://www.icorinternational.com/index.php?main_page=page&id=25&chapter=0:( (http://www.icorinternational.com/index.php?main_page=page&id=25&chapter=0:%28)
Again...a poor choice of words. They are not referring to bubbles, it's the cloudy appearance one must be aware of.

It also reads

R-414B is less dense than R-12 or R-134a and should be weighed in when charging.
How many field piped walk-ins have a specified amount of charge? None, the length of the field piping determines how much refrigerant they need.


It also reads

When using a Dial-A-Charge, charge at 100%. These devices charge by volume and not by weight.
See what I mean, the reason they say to use 80 or 90 percent is because it's lighter than the refrigerant it replaces. You still need the same volume.

Bottom line, I've been doing retrofits since the CFC phase out and MP-39 first hit the shelves. I bought one of the first bottles shipped to the Atlanta market. I have 9 trucks on the road and have done literally thousands of retrofits. Get the bubbles out of the glass and send a full column of liquid to the TXV or it isn't working right. If you're checking SH you'll know that.

[icehouse]

Again...a poor choice of words. They are not referring to bubbles, it's the cloudy appearance one must be aware of.

It also reads

How many field piped walk-ins have a specified amount of charge? None, the length of the field piping determines how much refrigerant they need.


It also reads

See what I mean, the reason they say to use 80 or 90 percent is because it's lighter than the refrigerant it replaces. You still need the same volume.

Bottom line, I've been doing retrofits since the CFC phase out and MP-39 first hit the shelves. I bought one of the first bottles shipped to the Atlanta market. I have 9 trucks on the road and have done literally thousands of retrofits. Get the bubbles out of the glass and send a full column of liquid to the TXV or it isn't working right. If you're checking SH you'll know that.
[/SIZE]
:( Not arguing, used MP39 when I had a problem with "Hot Shot" and that is the info they gave me when I questioned them.

[k-fridge]

:( Not arguing, used MP39 when I had a problem with "Hot Shot" and that is the info they gave me when I questioned them.
MP-39 is a fine refrigerant. I'm not a fan of HotShot or ICOR, I won't go into details but I have some issues with their engineering and their ethics.

R-409 is another R-12 replacement that I've had good success with for medium temp applications.

[icehouse]

MP-39 is a fine refrigerant. I'm not a fan of HotShot or ICOR, I won't go into details but I have some issues with their engineering and their ethics.

R-409 is another R-12 replacement that I've had good success with for medium temp applications.:D

I can ust imagine, they tried to tell me that "Hot Shot" is better than MP66 on low temp. I'll stick with DuPont, after-all they are a leader in the Refrigerant business. Some tech rep. from Icor called me today and still swore up and down that if you clear the sight-glass, unit is overcharged. When questioned about headmaster, he said that statement is wrong? go figure.

[k-fridge]

:D

I can just imagine, they tried to tell me that "Hot Shot" is better than MP66 on low temp. I'll stick with DuPont, after-all they are a leader in the Refrigerant business. Some tech rep. from Icor called me today and still swore up and down that if you clear the sight-glass, unit is overcharged. When questioned about headmaster, he said that statement is wrong? go figure.
No R-12 replacement blend I know of is better than MP-66 at low temp, certainly not HotSnot. Even R-409 (which I find is very good at med temp) is not very good at low temp.

Well, that engineer's statements to you shows how much he knows. Next time ask him how many rooftops he's been on trying to get a walk-in running again. Bet he's never been out of his cushy little cubicle, much less had his hands dirty. :D