Capillarys and Compressors

[ArchEngineer]

Hi,

New here so I'll try to be quick.

I installed a compressor that I bought from coldparts.com in an old True freezer unit that I carted off when I sold the guy a new one. The compressor was advertised as a Tecumseh AEA2424Z with 2800 BTU @ -10 deg. When I installed it did not cool below about +30 and I noticed that it had very high head pressure. I assumed plugged cap tube but when I took if out it seemed fine. Looking further into the compressor side I noticed that what I received was a CAE2424Z so I called Tecumseh and they said it's a European style and the numbers don't mean the same as in the states. In the end he said it was about 1900btu @ 10 deg. Also when I went to replace the capillary tube, Supco says 29", but the existing tube is about 70" though.

My question is could this long cap tube combined with an undersized compressor be source of the high head pressure and poor cooling? Or if the cap is clear would it work okay and just not have the cooling power of the bigger unit? One more thing, the compressor was smaller than the original but I wieghed in the factory charge so it may have been slighty overcharged as well.

Thanks for any insight!

[monkey spanners]

CAE2424Z is a 2400btu/h, 1/2hp, low back pressure, R404A compressor.

C means single phase, AE is model/family, 2 is LBP/high starting torque, 4 is number of figures in btu rating, 24 first two firgures of btu rating (24 plus two zeros to get 2400), Z is R404A

Jon

[Gary]

Hi,

New here so I'll try to be quick.

I installed a compressor that I bought from coldparts.com in an old True freezer unit that I carted off when I sold the guy a new one. The compressor was advertised as a Tecumseh AEA2424Z with 2800 BTU @ -10 deg. When I installed it did not cool below about +30 and I noticed that it had very high head pressure. I assumed plugged cap tube but when I took if out it seemed fine. Looking further into the compressor side I noticed that what I received was a CAE2424Z so I called Tecumseh and they said it's a European style and the numbers don't mean the same as in the states. In the end he said it was about 1900btu @ 10 deg. Also when I went to replace the capillary tube, Supco says 29", but the existing tube is about 70" though.

My question is could this long cap tube combined with an undersized compressor be source of the high head pressure and poor cooling? Or if the cap is clear would it work okay and just not have the cooling power of the bigger unit? One more thing, the compressor was smaller than the original but I wieghed in the factory charge so it may have been slighty overcharged as well.

Thanks for any insight!

You seem to be looking for a design flaw in a system that worked properly for many years... one of many thousands of such systems that are working properly.

Why not start with the assumption that the system components are designed/sized properly, but something has gone very wrong? The question you should be asking yourself is, "What killed the original compressor?"

It is going to be difficult to help you if you insist on giving us opinions instead of measurements, e.g. "high head pressure" (opinion) instead of "____psig head pressure" (measurement).

What we/you need to know is:

Evap air in temp
Evap air out temp
Saturated suction temp (convert from pressure)
Suction line temp at evap outlet
Suction line temp at compressor inlet

Cond air in temp
Cond air out temp
Saturated condensing temp (convert from pressure)
Liquid line temp at receiver outlet

[nike123]

What was original compressor model number?

[ArchEngineer]

I called Tecumseh and they told me the CAE2424Z is from their European factory in France. They also said that the numbers do mean the same as in the US and that this compressor was actually rated at about 1900 btu. Not surprising then about not cooling properly! Coldparts is sending a different compressor so I'll replace the cap tube when it gets here it and see what happens.

[Fridgy Dave]

Change the capillary for the correct size and this system will work much better. Your high head pressure is due to a flow restriction through the cap with the reduced capacity of the comp the unit wont work as efficiently but it will work better than you have described