Trying to decide what to do about broken A/C

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Trying to decide what to do about broken A/C

Postby dwolfe002 » Sat May 04, 2013 3:43 pm

Let me start out by saying that I know I'm probably not supposed to do this but I am on a fixed income. I do know enough about HVAC to be dangerous but am hoping to find a pro to start the new unit up after I install it.

I have an old 1997 3 ton coleman split system air conditioner and furnace. The furnace is an EB15 but almost all the condenser info is faded out. It looks like the unit charge (R-22) was 3.25 pounds. Since money is a concern, I want to replace the condenser with either a new straight A/c or even possibly install a heat pump to help out with the electric bills in the winter time. The thermostat in the mobile home is a 4 wire thermostat but it does have an 8 wire harness. The compressor has a 3/8 liquid line and a 3/4 suction line.

Questions I -

1) This 3 ton compressor has a 3/4 suction line and a pretty small charge. New 3 ton units all seem to have a 7/8 suction line and a much larger charge. Can I use the 3/4 line on a new unit in order to keep the original evaporator coil?

2) The new 2 1/2 ton units do have a 3/4 suction line and much larger charge and more than likely at least 3 seer rating higher. The mobile home is slightly less than 1000 sq. ft. Would a 2 1/2 ton unit possibly be big enough due to increased seer ratings or do other things have an effect?

3) I'm not real familiar with heat pump thermostats but basically does the orange (reversing valve) wire go directly to the heat pump or does it go to another connection in the heat exchanger? If it does, should there be any other problems with installing a heat pump instead of straight A/C?

4) My last option is to put in a R-410 A/C or heat pump. I realize that I will have to change the lineset and the evaporator coil so that is my last option. What I don't know is that if it work properly with an old heat exchanger.

Like I said before, I know everything should be matched up but I cannot afford to replace everything but would really appreciate any answers you may have to the above or any suggestions.

Thanks for your time and trouble.
dwolfe002
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- Trying to decide what to do about broken A/C

Postby Freon » Sat May 04, 2013 8:40 pm

This 3 ton compressor has a 3/4 suction line and a pretty small charge. New 3 ton units all seem to have a 7/8 suction line and a much larger charge. Can I use the 3/4 line on a new unit in order to keep the original evaporator

Most likely, Yes, but check the installation manual. The length of tubing is also a consideration in determining diameter required.
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The new 2 1/2 ton units do have a 3/4 suction line and much larger charge and more than likely at least 3 seer rating higher. The mobile home is slightly less than 1000 sq. ft. Would a 2 1/2 ton unit possibly be big enough due to increased seer ratings or do other things have an

That's a heat calculation question. SEER has nothing to do with cooling capabilities. All SEER says is you have a more efficient unit cooling your house. If the old unit and new unit have the same BTU/hr capacity, then you'll be fine, assuming you were fine before.
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3) I'm not real familiar with heat pump thermostats but basically does the orange (reversing valve) wire go directly to the heat pump or does it go to another connection in the heat * If it does, should there be any other problems with installing a heat pump instead of straight A/*

The orange wire goes to the outdoor condenser unit where the reversing valve is located. However the usual path is from the thermostat to the air handler where it is connected to a similar orange wire coming from the condenser unit.
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My last option is to put in a R-410 A/C or heat pump. I realize that I will have to change the lineset and the evaporator coil so that is my last option. What I don't know is that if it work properly with an old heat exchanger.

What do you mean... 'work with a heat exchanger'. Your new evaporator coil is the heat exchanger for the heat pump system. The only other heat exchanger could be for a furnace as backup heat on very cold nights.
Freon
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- Trying to decide what to do about broken A/C

Postby dwolfe002 » Sat May 04, 2013 9:03 pm

It looks like so far that all 3 ton units use a 7/8 suction line. I checked a couple installation manuals but they don't say anything about using a different size line. I'll check some more. By the way the lines will be approximately 15 ft.

My mobile home has a 3 ton A/C unit in it now. When it worked, it would cool it to any temp you wanted. I was more wondering if a 2 1/2 ton would work with a 3 ton air handler. I believe the trailer would cool fine with 2 1/2 but am not completely sure.

As far as the R-410 unit, I'm not really sure why I even asked that question. I have had a stoke so the old brain doesn't work like it used to.

Thanks for the info.
dwolfe002
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