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superba

Compressor sounds like a pea thrasher

16 posts in this topic

Hi,

Added: I just did some quick research and found that SnyderGeneral was acquired by Singer and then by Inter-City; I doubt that anyone has any definitive information but have at it if you do. United Technologies got in the act somehow as well.

This is a rented place. I informed the owner that the outside compressor was making noise, rattling, etc., and needed to be replaced or serviced. His response was 'yeah, the last tenants complained of the same thing'.

Early on I oiled the fan shaft through the oiler holes but that didn't change anything. The compressor sits outside in the weather and all the nameplate information was on foil or paper stickers and is worn off.

The indoor unit is where I got the model number; it was manufactured 1/89. The "cased indoor coil" is Model U24A15 and it contains Model U24A00 coil. The coil pressure rating is 150psig using R22.

The high side of the compressor is not very hot and the low side is not very cold to touch indicating to me that it is low on R22. I have manifold guages and could take the pressure/temperature if that would help.

Functional cooling is marginal. In other words the system will bring the temperature down to my target indoor setting of 78 F after awhile. When the ambient is over 95, the indoor temp nevers goes below 80 F.

I'd like to know if there is/are any things I can do to improve the cooling and keep the compressor from outright failure. I would make the owner pay the costs of a failure, but I would suffer heat while getting it fixed.

I live in Sacramento, CA, where the ambient is between 95 and 105 F July, August, September.....

TIA.

Cheers!

Jim

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Need appliance parts? Call 877-803-7957 now!

Your Landlord is in for a hefty bill. Estimated service life of A/C equipment is 10-15 years. The Gubbernment has raised the minimum efficiency standard from 10 SEER to 13 SEER (1 SEER = 1 Btu transfered per watt of power consumed).  13 SEER equipment has been running about 40-50% higher cost than a comparably sized 10 SEER equipment. There is no way to service a noisy compressor other than to replace it. Sounds like your evap coil is a 2-ton unit (24,000 btu/hr capacity). It isn't economical to change compressors on most older units and I find it is much easier to change the entire condensing unit, especially when they come pre-charged.

Nice easy job if the old comp is still running. Get your low side gauge on and shut off the high-side service valve. When the low side is in a vacuum, close that valve too. Hacksaw the lineset, disconnect power and remove the line and ctrl wire, remove the old cond and put aside. Clean up the lines, adapt whatever needs adapting, put on a liquid line f/d, braze it up, vac it out and open the service valves on the new one. Up and running in two hours or less.

Some suppliers may still have some 10 SEER stock left, call around and ask for it.

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A Jedi does not use a hack saw.  The ways of the Force forbid it.

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[user=9503]AccApp[/user] wrote:

Nice easy job if the old comp is still running. Get your low side gauge on and shut off the high-side service valve. When the low side is in a vacuum, close that valve too. Hacksaw the lineset, disconnect power and remove the line and ctrl wire, remove the old cond and put aside. Clean up the lines, adapt whatever needs adapting, put on a liquid line f/d, braze it up, vac it out and open the service valves on the new one. Up and running in two hours or less.

Some suppliers may still have some 10 SEER stock left, call around and ask for it.

Are you suggesting that I replace the compressor if I can find a 2hp 10 SEER unit? You make it sound easy, and it might be, but I don't do that sort of stuff every day. I grew up in an old time machine shop and I'm pretty good at that sort of thing, but there is a learning curve with everything I do.

I'm looking into an ad that offers big rebates, but I doubt that I can get Scrooge to pop for that. He'd rather wait until the system fails just to be sure it's going bad even though it's ~17 years old and you said the useful life expectancy is ~10 - 15 years.

Thanks for your help.

Cheers!

Jim

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A way that you can get him to pay for it with no choice. Shut off the power. Reverse the common wire on the compressor with the start winding wire and turn the power on. This will ruin the compressor and he will have to buy a new one. Once it quits just put the wires back and he will never know.

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[user=10622]HVAC techy[/user] wrote:

A way that you can get him to pay for it with no choice. Shut off the power. Reverse the common wire on the compressor with the start winding wire and turn the power on. This will ruin the compressor and he will have to buy a new one. Once it quits just put the wires back and he will never know.

Hi, a man after my own heart. I wouldn't want to do that, not yet, anyway. My WAG is that it will fail soon enough, anyway.

HST, I could sneak and replace the compressor as AccApp suggested above, but I have another idea. It wouldn't be smart to describe it at this point.

My situation is that I'm not flush with money, the house is costing more than I thought it would, it's hotter than the hinges of hell in Sacramento this time of year, and I just want to be cool until I work out something else.

I looked into a full page ad in the Sacramento Bee about replacing the system with a new Carrier system with lots of rebates, etc. I thought that might be a way to go, but the guesstimate I got was $7 to $10,000. I'd never get him to go for that. Part of that cost is a reworking/upgrading of the ducting system required by a new law that went into effect in 2005, la de dah.

If anyone can think of a low cost way to keep this old dog of a compressor running, I'd like to hear it.

TIA.

Cheers!

Jim

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The best thing is keep your condenser clean and cool.

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Surely the Force is with exsearsguy for he makes an excellent point.  It couldn't hurt and it may help to simply rinse the condenser coil outside with a garden hose.  Cut the power, lift the fan and squirt the water from the inside to the outside.  But before you do anything hook up those gages and let us know what kind of pressures you have.

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[user=2]Jedi Appliance Guy[/user] wrote:

Surely the Force is with exsearsguy for he makes an excellent point. It couldn't hurt and it may help to simply rinse the condenser coil outside with a garden hose. Cut the power, lift the fan and squirt the water from the inside to the outside. But before you do anything hook up those gages and let us know what kind of pressures you have.

Hi,

Okay, just measured the high and low side at the compressor.

Low - 65psi Temp - ~38 F

High - 246psi Temp - ~116 F

I double checked these numbers with a chart for R22 and they are correct.

Outside temp is ~105 F and inside on digital thermostat is 80 F.

Schrader valve on high side didn't seal off properly when I unscrewed the test hose and momentarily scared the crap out of me, but it sealed and I recapped it.

The high side tubing looks like it was spliced before indicating that the compressor may have been changed some time in the past.

Thanks for your help.

Cheers!

Jim

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The house is pretty loaded at 80F and the out side amb is pretty high as well. I would be curious as to your suction line temp by your low side schrader valve. That will tell me the superheat measurement. Make sure your condenser coil is clean from any blockage. From the pressures and temps you mentioned it sounds low on refrigerant though. On 105F day 246psi is low. On a old unit the rule of thumb only as a guide is the high side psi converted to temp on the gauge under R22. You should have ambient temp plus 30 equals your pressure. I think I said that right.

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[user=10622]HVAC techy[/user] wrote:

The house is pretty loaded at 80F and the out side amb is pretty high as well. I would be curious as to your suction line temp by your low side schrader valve. That will tell me the superheat measurement. Make sure your condenser coil is clean from any blockage. From the pressures and temps you mentioned it sounds low on refrigerant though. On 105F day 246psi is low. On a old unit the rule of thumb only as a guide is the high side psi converted to temp on the gauge under R22. You should have ambient temp plus 30 equals your pressure. I think I said that right.

Hi,

If I understand you correctly, the high side pressure should be whatever is opposite 135 F on the guage. (105 + 30 = 135). 135 F is opposite 320 psi on the R22 scale. Is that right?

How do I measure suction line temp near the low side schrader valve? Wouldn't that be the low side pressure and its equivalent temperature? If that's it, it measured 65psi with equivalent temp of 38 F.

By the way, the pressure/temp charts I refer to are HERE .

Is R22 available to consumers? I can load it if it is.

What's next? I still need to clean the heat exchanger around the compressor and the cooling coils inside if I can.

Thanks for your help.

Cheers!

Jim

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How do I measure suction line temp near the low side schrader valve? Wouldn't that be the low side pressure and its equivalent temperature? If that's it, it measured 65psi with equivalent temp of 38 F.

Use a thermometer. You need to check the actual temp at the line as close to the cond as possible. I use a clamp on thermocouple attached to my digital thermometer but even a dial type thermometer with some insulation around it and the line should give you a close enough temp. When you compare actual temp with the temp from the pressure chart you can then calculate superheat. Check the High side line's actual temp as well to calculate subcooling.

You will need a refrigerant license to purchase R22. You can do an open book test online for about $100.

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[user=9503]AccApp[/user] wrote:

Use a thermometer. You need to check the actual temp at the line as close to the cond as possible. I use a clamp on thermocouple attached to my digital thermometer but even a dial type thermometer with some insulation around it and the line should give you a close enough temp. When you compare actual temp with the temp from the pressure chart you can then calculate superheat. Check the High side line's actual temp as well to calculate subcooling.

I have a thermocouple on my DVM that I seldom use. I should be able to slip it into the foam insulation around the low side, return, line. Others have peeled the foam slightly to touch the line. On the high side at the condenser, I'll tape the probe on as close to the housing as possible. Is that satisfactory?

AFA the cert test is concerned, do you know who gives those, Vue, Prometric, etc.? How can I prepare so I have an even break? Maybe I'll become an air conditioning weenie.

Thanks for continuing to help.

Cheers!

Jim

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Hi,

I measured the temperatures at the cooling coil sitting on top of the furnace.

High Side: got it where the copper tubing entered the cooling coil housing grommet. Taped a solid state probe to it while running for at least 10 minutes. Temp: 104 F.

Low Side: pushed the probe into a tear in the foam between the foam and the return line about 12 inches from the cooling coil. Temp: 77 F.

Ambient temp in the shade here today was ~100 when temps taken. Thermostat set for 78 F; has been maintaining but I expect it to warm up to ~81 as it gets hotter.

I hope the temps were taken in the right place. Let me know if you want other readings. I still haven't cleaned the evap coil with water; I'll do it when it gets cooler.

Thanks for the continued help.

Cheers!

Jim

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You can take your EPA cert test from these guys Mainstream Engineering. You sound like you can easily pass this open-book test. Did I mention the test was open-book?

I was wrong, the open-book test is now only $24.95. Pretty scary to know that any huffer with $25, Adobe PDF reader and the ability to read can get EPA certified as a section 608 type I tech.

Temps without pressures usually mean nothing, but a low side near coil temp of 77° is way too high of a temp! Juice that baby up. That means your coil is probably around ~70° at least. Just to be thorough, get pressure and temp near the service valves on the outside unit.

I know it's a little late for this, but what is a pea thrasher? Do peas need to be thrashed?

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[user=9503]AccApp[/user] wrote:

Temps without pressures usually mean nothing, but a low side near coil temp of 77° is way too high of a temp! Juice that baby up. That means your coil is probably around ~70° at least. Just to be thorough, get pressure and temp near the service valves on the outside unit.

I know it's a little late for this, but what is a pea thrasher? Do peas need to be thrashed?

Hi,

Easy one first. Peas that were left over from green peas already harvested were run through a thrasher which literally beat the dried pea pods until the peas themselves came out. The resulting noise was, well, loud as a pea thrasher. I doubt if there are any of them left running.

Actually, I did do the measurements on the outside unit at the schrader valves of each side. The pressures and corresponding temps for R22 are read directly from the guages, but I also double checked them from a table.

Low - 65psi Temp - ~38 F

High - 246psi Temp - ~116 F

I double checked these numbers with a chart for R22 and they are correct.

Outside temp was ~105 F and inside on digital thermostat is 80 F.

I got the other info on the cert tests. I'll have to see if I can work as an indy here, but I doubt it.

Thanks for your ongoing help.

Cheers!

Jim

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