Old HEIL CA3048VKA1 A/C Not Cooling


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Old 08-12-12, 04:06 PM
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Old HEIL CA3048VKA1 A/C Not Cooling

This is an old system HEIL A/C unit date is 2/89
Model: CA3048VKA1
R22

I remember our central A/C working very well when we first moved into this house about 12 years ago - it would actually get too cold. It lost refridgerant and the service company installed a new evaporator coil about 6 years ago. I never felt that it worked as well after this repair, seemed to run longer for the same cooling. Lately it took an hour to drop even one degree but seemd to dehumidify well so we just ran it for short periods of time. Today it is not cooling at all, outside it is just blowing the same temp as the outside air inside vent temp seems to be no cooler than room air. Interior and exterior blowers are running but I'm not sure if the compressor is even running. I know that I probably need to call a service guy out but I'd like to be well informed in order to understand what he might have to say or if possible repair it myself. Is there a relay that I can check for the compressor, or a low coolant shut off sensor? Any suggestions?
Thanks in advance,
Pete
 
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Old 08-13-12, 05:16 AM
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Anyone know where I can find a schematic for this unit? I do know electrical systems well so I just want to measure some voltages to get an idea of what is going on.
 
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Old 08-13-12, 04:35 PM
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Took the covers off and it looks very simple, schematic is in there also.
Contactor control goes straight to basement control unit and it activates when calling for cooling. 242V on the line side and 242V on the side to the compressor. There is a motor cap but it is for the blower, and it runs fine.

Edit: It is a dual cap and there is one for the compressor the connection was far more rusty than the others - cleaned it. Still no run.

I think there were 3 wires coming out of the compressor, two go to the contactor, did not check the other, is it ground? Edit: third is the cap, and there are two blacks at the bottom that I think go to line before the contactor.

Edit: Fliped open the waterproof cover on the compressor and the spade connector on the red heavy guage wire is completely rusted through, connector on the compressor is fine. This is a 60A circuit and that spade connector looks way too small for 60A. The cap spade was loose probably from all the heat. I'm sure this is the problem and I'll put new connectors on tomorrow it is dark now.

I'm going to clean the unit tomorrow if those conections fix the problem is there anything else I should do while I have it open?

I don't know these systems well, is there a shutoff pressure sensor in the compressor or is the compressor bad?

Can the compressor alone be replaced for a reasonable fee, everything else looks fine?
 

Last edited by Pete2010; 08-13-12 at 05:18 PM.
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Old 08-14-12, 02:15 PM
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The HD I went to was out of slip on connectors that accept 10 Ga wire and I think it is far too small anyway so I got a copper screw terminal lug and used it to connect to the terminal. Cleaned up all the other connections and it is running fine, house is reasonably cool after half an hour. Seems to be working a bit better than it has all season.

I'll try to get some temp measurements.
 
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Old 08-15-12, 11:32 AM
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Great job Pete2010; I hope you tripped the breaker off to the condensing unit & discharged the run capacitor; safety first.

If you want to check how well your A/C is performing...

Want us to be enabled to check the ballpark performance of your system... so you can call an HVAC Contractor if it needs servicing?

All U need is a good thermometer (digital reading in tenths preferable) & and indoor Humidity Gauge

1) Helpful; Tonnage & SEER of Unit &/or outdoor condenser model number: minimum SEER upped to 10-SEER in 1987

2) TXV or, orifice metering device? _______. Only if U know…

3) Outdoor condenser’s discharge-air-temperature ______-F
Subtract Outdoor air temperature: _______
Outdoor Condenser Air-Temp-Split _______

4) Need the ‘Indoor’ percent of relative humidity - in the middle of the rooms or, at Return-Air inlet grilles ___
5) Indoor Return-Air Temperature ______
Subtract Indoor Supply-Air Temperature ______ -F
Indoor temperature-split _______-F

If U can find a turn in the small liquid line insulate the temperature-probe; get its temperature for the subcooling analysis:
Small liquid line temperature ____

It is all up to you...?
 
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Old 08-15-12, 05:47 PM
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Thank you! I don't have a good thermometer so I'll try to pick one up soon.
I did shut off the outside breaker, was tempted to do the inside also just to be 1000% sure.
I did check for voltage even after shutting off the breaker.

The 2 main power wires on the compressor and 3rd cap wire were at the top. There were also 2 black wires from the bottom of the compressor that are always powered since they are connected to the hot side of the contactor. What are these for?

Thanks again,
Pete
 

Last edited by Pete2010; 08-15-12 at 07:54 PM.
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Old 08-15-12, 08:00 PM
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Picture of the repair using a screw terminal lug and the old burnt up lug.
The slip on part is completely gone, melted from the heat.
Hope this works.
 
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Old 08-16-12, 06:31 AM
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Thank you! I don't have a good thermometer so I'll try to pick one up soon.
I did shut off the outside breaker, was tempted to do the inside also just to be 1000% sure.
I did check for voltage even after shutting off the breaker.

The 2 main power wires on the compressor and 3rd cap wire were at the top.

There were also 2 black wires from the bottom of the compressor that are always powered since they are connected to the hot side of the contactor. What are these for?
Thanks again, Pete
They're probably for a crank case heater that keeps liquid refrigerant from settling into the compressor oil which would foam it out into the lines on start-ups.

Good photos of the job; way to go...
 
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Old 08-16-12, 04:08 PM
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Thanks again, interesting about the heater I'll be sure to remember to hit the breaker for the winter.
 
 

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