Tecumseh compressor help..

[wannafreeze]

Hi guys,I need help with this compressor info.
Tecumseh AH7511B
Is it an R22 compresssor?
Do you know if there is a link in tecumseh site to convert this to a new compressor model#?
Thanks.

[k-fridge]

If memory serves its R12 med temp. Common walk-in cooler compressor in it's day.

11'000 BTU at +25 evap......I think.

[icehouse]

Hi guys,I need help with this compressor info.
Tecumseh AH7511B
Is it an R22 compresssor?
Do you know if there is a link in tecumseh site to convert this to a new compressor model#?
Thanks. This should help http://www.tcc-nacg.com/

[wannafreeze]

If memory serves its R12 med temp. Common walk-in cooler compressor in it's day.

11'000 BTU at +25 evap......I think.

The walk-in box I checked today has an R22 TXV.It might be a 1/2 ton valve(I am not sure though,it was a tight spot for a posthernia-surgery-job).
Condensing unit is a water cooled R12 unit with a new R22 compressor on it.(AJA9484EXD)
The LPC would cut out at the start because head pressure couldn't build up.Adjusted the reg.valve,raised the HP to 225-230 PSI.Still pressure drops too much.I will intall a solenoid-thermostat pair next week.But I am thinking about the mismatch issues.Mainly the water coil..

[k-fridge]

The walk-in box I checked today has an R22 TXV.It might be a 1/2 ton valve(I am not sure though,it was a tight spot for a posthernia-surgery-job).
Condensing unit is a water cooled R12 unit with a new R22 compressor on it.(AJA9484EXD)
The LPC would cut out at the start because head pressure couldn't build up.Adjusted the reg.valve,raised the HP to 225-230 PSI.Still pressure drops too much.I will intall a solenoid-thermostat pair next week.But I am thinking about the mismatch issues.Mainly the water coil..

As long as the head pressure is OK the water coil shouldn't be a problem. Maybe a TXV issue?

As an aside, you might check the size of the suction line. Most of those R-12 compressors of that size used a 7/8 suction line, an R-22 compressor of the same size probably needs 5/8s to get the proper refrigerant velocities for oil return.

Now that I think about it, you could have an oil logged evap that is causing the problem.

[icehouse]

As long as the head pressure is OK the water coil shouldn't be a problem. Maybe a TXV issue?

As an aside, you might check the size of the suction line. Most of those R-12 compressors of that size used a 7/8 suction line, an R-22 compressor of the same size probably needs 5/8s to get the proper refrigerant velocities for oil return.

Now that I think about it, you could have an oil logged evap that is causing the problem.
You are right there. Embrco now packs a special lubricant with their replacement compressors (R-12) to be added when using R-22 base blends to insure proper oil return.

[wannafreeze]

As long as the head pressure is OK the water coil shouldn't be a problem. Maybe a TXV issue?

As an aside, you might check the size of the suction line. Most of those R-12 compressors of that size used a 7/8 suction line, an R-22 compressor of the same size probably needs 5/8s to get the proper refrigerant velocities for oil return.

Now that I think about it, you could have an oil logged evap that is causing the problem.

I noticed the suction line.by the condensing unit its a 1/2 line,at some point its the old line I think it was 5/8..with no insulation going through a boiler room.I suspect the txv might be undersized too.when it reaches temperature low side droppes to 35-32 PSI..from 43-45 in a rapid manner..plus the old filter is still in the line.what does that tell you..
when the customer is a cheap one that uses cheap underqualified people and you service them first time there are accumulation of mistakes and its hard to get it to their head.I asked him how much he spent for the new compressor(by the way it has all kinds of noises already) he says $600.Oriental guy servicing oriental guy.The guy next door is a good customer of mine that gave my number to this guy,I slapped him around for 1 week.He didn't give up.Otherwise I don't service them for cheap reasons..:eek:

[k-fridge]

I noticed the suction line.by the condensing unit its a 1/2 line,at some point its the old line I think it was 5/8..with no insulation going through a boiler room.I suspect the txv might be undersized too.when it reaches temperature low side droppes to 35-32 PSI..from 43-45 in a rapid manner..plus the old filter is still in the line.what does that tell you..
when the customer is a cheap one that uses cheap underqualified people and you service them first time there are accumulation of mistakes and its hard to get it to their head.I asked him how much he spent for the new compressor(by the way it has all kinds of noises already) he says $600.Oriental guy servicing oriental guy.The guy next door is a good customer of mine that gave my number to this guy,I slapped him around for 1 week.He didn't give up.Otherwise I don't service them for cheap reasons..:eek:

Uh oh, you're going behind a hack huh? Wow! I think I'd start by changing the driers and making sure the TXV is the right size and has a clean strainer. You may need to blow out the evap with nitrogen too. If it has a suction filter I'd just take it out of the system.

[gerryboy00]

AH7511B
11,000 btu @ +20° B mean R-410A




AJA9484EXD
8,400 btu @ +20° E mean R-22


http://www.tcc-nacg.com/service_data.php#

[k-fridge]

AH7511B
11,000 btu @ +20° B mean R-410A




AJA9484EXD
8,400 btu @ +20° E mean R-22


http://www.tcc-nacg.com/service_data.php#

R-410 didn't exist when that compressor was made. It was changed to an AHA and then the AHA series was replaced by AVA...I think.

[wannafreeze]

AH7511B
11,000 btu @ +20° B mean R-410A




AJA9484EXD
8,400 btu @ +20° E mean R-22


http://www.tcc-nacg.com/service_data.php#

I think the nomenclature's B is not the same B..
That compressor looked like 20 yrs old.
I had my supply house guy convert this kind of Mn. before but today they were closed.

[gerryboy00]

oh, I see....

[icemeister]

From my Tecumseh info, the current number for the AH7511B would be an AHB7511AXD which is a 230V 1 Ph MT R12 pump with a capacity of 12,000 Btuh @ +20ºF evap temp.

The AKA9484EXD is a MT R22 compressor with a capacity of 8400 Btuh @ +20ºF evap temp., so that's significantly short.

To get a better match to the original capacity, I'd go with an AWG4520EXN which is a HT R22 with a capacity of 11,000 Btuh @ +20ºF evap.

Of course, it's always advisable to recheck your evaporator capacity and box load and try go get a good balance all around.

[wannafreeze]

From my Tecumseh info, the current number for the AH7511B would be an AHB7511AXD which is a 230V 1 Ph MT R12 pump with a capacity of 12,000 Btuh @ +20ºF evap temp.

The AKA9484EXD is a MT R22 compressor with a capacity of 8400 Btuh @ +20ºF evap temp., so that's significantly short.

To get a better match to the original capacity, I'd go with an AWG4520EXN which is a HT R22 with a capacity of 11,000 Btuh @ +20ºF evap.

Of course, it's always advisable to recheck your evaporator capacity and box load and try go get a good balance all around.
The WIB looked fairly new.Somehow the old R12 cond.unit worked with it till compressor went bad.(According to the customer the water supply wasn't there one night and took the old compressor out.)

[gerryboy00]

To get a better match to the original capacity, I'd go with an AWG4520EXN which is a HT R22 with a capacity of 11,000 Btuh @ +20ºF evap.

.


Ice, by looking at this chart........Compressor Model Number Codes

http://img267.imageshack.us/img267/3860/t7i967596rct6.jpg


the number AWG4520EXN mean :

4 : high temp. application 45°
5 : Number of Digits In Rated BTU Capacity, so 5 digit
20 :First Two Digits of Rated BTU Capacity, so 20,000 btu

???is it

[k-fridge]

Ice, by looking at this chart........Compressor Model Number Codes

http://img267.imageshack.us/img267/3860/t7i967596rct6.jpg


the number AWG4520EXN mean :

4 : high temp. application 45°
5 : Number of Digits In Rated BTU Capacity, so 5 digit
20 :First Two Digits of Rated BTU Capacity, so 20,000 btu

???is it

True, but here it's being used in a medium temp application. On the medium temp scale the capacity is rated at a +20* evap.

A lot of the R-22 compressors are rated for high temp in an A/C application and medium temp refrigeration application.

[gerryboy00]

True, but here it's being used in a medium temp application. On the medium temp scale the capacity is rated at a +20* evap.

.

btu rating from 20,000 high temp. to 11,000 med. temp ?????

9,000 less??:confused:

[wannafreeze]

btu rating from 20,000 high temp. to 11,000 med. temp ?????

9,000 less??:confused:

one of the best things I learned from the pros at this forum is this issue.In one of my post this is answered.If you check from tecumseh compressor books you will see the capacity goes with the application.you can use a higher temp.compressor for a lower evap.temp.with less capacity.(It's listed.)
Also another thing I learned that completes this is HP versus capacity..
I wasn't tought this in school.
I first noticed this fundemantal refrigeration issue when I questioned a high temp (4461) compressor being used for medium temp box with a 1/4 ton valve.
that day was a turning point in my refer career.
http://www.hvac-talk.com/vbb/showthread.php?t=102088

[k-fridge]

btu rating from 20,000 high temp. to 11,000 med. temp ?????

9,000 less??:confused:

I don't have a capacity chart in front of me, but could be.

Capacity also varies with condensing temperature. For example, a particular Copeland compressor I'm familiar with is rated at 9000 BTU in a single fan condensing unit and 11000 BTU in the twin fan unit. This is also why you see seemingly undersized compressors in high efficiency A/C condensing units. A three ton unit may have a 2.5 ton compressor in it, but at the lower condensing temperature the high eff units run the compressor is actually rated at around 36000 BTU.