Basement Air - New Compressor is Installed !

[Bug512]

Well we now have two working compressors on out basement air unit !

Lats year I noticed that the cooling was not so good along with the low amp draw that there was a problem.
So I pulled the unit out to find that circuit #1 was empty, there we found a leak at one of the condenser u-tubs, we tried to braze it but there was also a leak where the fins were. What to do? Replace the condenser, $400 later we have two fully charged units.

Also found that the indoor blower motor had become separated from the units housing.

Fast forward a couple of weeks..

Oh no! why is compressor #1 not running? Well it looks like since #1 ran without a charge it locked up the compressor. I wish they put in low pressure switches.

So today we pulled the unit out once again and changed #1 compressor. Since the Panasonic's are no longer made we went with a Techmesh as per the manufactures instructions. Another $300

We also found a small leak on one of the u-tubs on the evaporator. After all our brazing was done both circuits were pulled down under 400 microns and the refrigerant was weighed in. Since it was only around 50 outside we ran the unit in heat pump mode and had 24-26 total amps and a 30 degree rise inside the motorhome.

Looking forward to the season and the performance of the unit. Glad I could do the work myself and if anyone has any questions please let me know.

Here are some pictures. Link

[Ray,IN]

Good pictures Gene, thanks. If/when mine ever has a problem I'll remember your post. Might write for instructions when the time comes.

[Wizard]

Great pictures, especially of your helper in the tote

[Bug512]

Thanks Ray, If I were to do it again I would look for a coach like yours.

Jerry, I wish I still had my little helper. Shadow passed early last year 12+ years with her. No clue how old she really was since we rescued her.

If you guys have any questions please ask and I will try to help.

[Spizzer]

Thanks, Gene. Great pictures and info.

jeff

[FIRE UP]

Jeff,
Great work. In all the projects/repairs/issues we've had with this present coach, an '04 Horizon 36GD with the 330HP CAT, that was one of the easiest ones I've done on it. The hardest part of removing our basement A/C was the four, long 1/2" bolts were severely rusted and I thought I was going to spin those welded nuts right out of the welds. But, some generous amounts of "Kroil" on each one for a bit of time and, eventually they all broke free and I could lower the unit enough to swing it out and work on installing a new motor bearing.

Speaking of swing out and lowering, I sure like your scissors jack. That looks really sweet for that application. Again, nice work.
Scott

[phinneyj]

I am gonna book mark this thread for future work on my own basement HVAC unit. Thanks.

[Duner]

Hey Gene, did you replace the outdoor metal squirrel cage with the new composite plastic one? Sure runs quieter and about 1 less amp draw. Was your duct work in the back in good condition or did you find separations causing leaks? Mine has separated twice in 10 yrs.

I've been following basement air issues for a lot of years and never heard of the indoor blower assy coming loose like that. Must of reduced the flow by a good percentage.

In the summer of 2008 I first pulled my unit and took pictures and documented the removal process. A lot of forum members have used it and saved a bundle of money. Here's a link that you can download for future reference:
https://docs.google.com/viewer?a=v&p...zBiZTYxYzU5ZWQ

[Bug512]

Hello Bill, I did not replace the blower, just oiled the bearings.

My ductwork was also in need or repair and resealing and with the blower motor attached to the casing of the unit there is much more airflow inside the motorhome.

I have read your documents and they are priceless, thank you for your hard work as I should have documented more.

This past Saturday I did a little testing in heat pump mode, with the ambient air temperature at 50-55 degrees I first ran the fan only (on high) to stabilize the temperature in the duct, staging on one compressor at a time and waiting 45 minutes in between I recorded entering and leaving temperatures, amperage and the delta between.

After two hours I had a delta of 30.2 degrees at 25 amps total.

I have more of the break down on the numbers at home.

I will have to wait a couple of more weeks to be able to run it in cooling mode and with the ambient temperatures higher my amperage should creep up some.

Thanks again for your note and I will record the cooling reading at a later date.

[FIRE UP]

Bug512,
May I ask, what kind of, and where did you get, that scissors jack your A/C unit is sitting on in the picture?
Scott

[Bug512]

Scott the lift was borrowed from work. It really is a handy cart to have.

Grainger link

[HD4Mark]

Great photos and helpful info Gene. We have had ours out about four times to work on it. I think three of them on a picnic table bench in a CG. What fun! I too used Duner's write up for a guideline.

We oiled the bearings one time and it worked for about one season. The next year the outside blower motor and bearing needed replacement. We bought the upgrade squirrel cage fan and ball bearing carrier bearing listed in Duner's guide. Had it recharged by a friend but I don't think that was necessary. Repaired the duct in the rear cap that was split and replaced the pricey thermostat.

It is hard to or possibly impossible to see while in place but the OD blower motor does have a small plug to oil it. We discovered that after replacing it and after some liberal amount of oil I could turn it by hand without the squeal. Tossed it anyway figuring if I have to pull the replacement I am putting in a new one.

[CaptBill]

Originally Posted by FIRE UP

Bug512,
May I ask, what kind of, and where did you get, that scissors jack your A/C unit is sitting on in the picture?
Scott

Scott,

I have a hydraulic lift cart very much like the one in Hene's pic, and I bought it in Harbor Freight. They have a 500 lb model, and a 1000 lb capacity (the one I bought). Not that I need the higher cap, but it has a larger work platform, and raises up higher than the smaller unit, so it is great for installing a window A/C, working on a lawn mower, etc.

If you buy one at H.F., make sure to clip or download a 25% off any one item coupon. I use them all the time.

[FIRE UP]

Originally Posted by CaptBill

Scott,

I have a hydraulic lift cart very much like the one in Hene's pic, and I bought it in Harbor Freight. They have a 500 lb model, and a 1000 lb capacity (the one I bought). Not that I need the higher cap, but it has a larger work platform, and raises up higher than the smaller unit, so it is great for installing a window A/C, working on a lawn mower, etc.

If you buy one at H.F., make sure to clip or download a 25% off any one item coupon. I use them all the time.

Hey Capt Bill,
Thanks for the heads up on looking at HF for one of these. This is one of those things that, I'd only use once in a great while but, it would sure be nice for certain applications.
Scott

[Bug512]

Update on AC and Heat Pump performance.

So with the warmer weather over the past weekend we were able to run the air conditioning and get some data, here is what we found.

For temperature measurement I used a thermometer (like this) with two inputs that calculate differential. You can use two thermometers as long as their at rest temperatures match.
Return measurement should be taken at the plenum area below the filter and the supply should be measured at one of the supply outlets closest to the air conditioning unit. Keep all registers / outlets open.

For measuring amperage I have a Fluke multimeter with a amp clamp.

Note: When performing each test I let at least 45 min of running so temperatures / pressures and amperage can stabilize.

Cooling test

Ambient air temperature was 75 degrees.

With only compressor #1 running and high fan speed (compressor #2 turned off at circuit breaker) we had a delta temperature of 8.2 degrees. When speaking to technical support at Airxcel they say a range of 8-12 is acceptable. My amperage for Circuit #1 was a total of 12.4 amps. This measurement was taken at the unit. This was also within range.

With both compressors running and high speed fan the delta settled out at 18.8 degrees. Again Airxcel says a range of 18-22 degrees is acceptable. My amperage for circuit #2 was a total of 9.9 amps.

So total amps of both circuits at 75 degrees outside is 22.3 amps.

Compressors should run at approximately 9.0 amps at 95 degrees ambient. Deduct 1.0 amp for every 5 degrees below 95. Airflow across the condenser will have input on this number also.

Heat Pump test

Ambient air temperature of 55 degrees

With only compressor #1 running and high fan speed (compressor #2 turned off at circuit breaker) we had a delta temperature of 10.3 degrees. My amperage for Circuit #1 was a total of 13.0 amps.

With both compressors running and high speed fan the delta settled out at 31.8 degrees. My amperage for circuit #2 was a total of 12.8 amps.

So total amps of both circuits at 55 degrees outside is 25.8 amps.

Again after speaking to Airxcel the range above for heat pump mode was acceptable. A higher delta and more amperage is normal.

What I am going to do in the future is get a amperage for each compressor only at the unit. I also might try to do a short video on how to do a performance test.

Please let me know if you have any questions as I know the basement AC threads are plenty.

Another note on compressors. The Panasonic compressors are no longer manufactured. After doing a lot of research and talking to Airxcel we used a Tecumseh model # RKA5512EXA Bill of Materials # RK147AT-021-J7
This included the overloads on the compressor. I purchased mine from Johnstone supply for $334.28 with NJ tax.
Refrigerant charge is the same at just shy of 2 pounds of R-22 per circuit.

I will update as I can get more data.

[bruceh]

Originally Posted by Bug512

Well we now have two working compressors on out basement air unit !

So today we pulled the unit out once again and changed #1 compressor. Since the Panasonic's are no longer made we went with a Techmesh as per the manufactures instructions. Another $300

We also found a small leak on one of the u-tubs on the evaporator. After all our brazing was done both circuits were pulled down under 400 microns and the refrigerant was weighed in. Since it was only around 50 outside we ran the unit in heat pump mode and had 24-26 total amps and a 30 degree rise inside the motorhome.

Do you have the Tecumseh part number? I can find:

TECUMSEH-61562807

on ebay for $200. It looks the same as our units but that can be deceptive.

How did you find the leaks? I am pushing my skill set here.

[Bug512]

Another note on compressors. The Panasonic compressors are no longer manufactured. After doing a lot of research and talking to Airxcel we used a Tecumseh model # RKA5512EXA Bill of Materials # RK147AT-021-J7