how to turn an air-conditioner into a heat pump (on a 1969 airstream trailer) - coleman heat pump

by:HICOOL     2019-09-01
how to turn an air-conditioner into a heat pump (on a 1969 airstream trailer)  -  coleman heat pump
I have a 1969 air flow ambassador travel trailer with raw air on itconditioner.
I like to upgrade things while keeping as original as possible.
I decided to rebuild the air-conditioner (
New compressor, new fan motor)
But when I was there I thought I would turn it into a heat pump too!
Heat pump is just an air-
Conditioner that can change the refrigerant path.
In cooling mode, the refrigerant enters the heat exchanger outside the cooling space from the compressor (condenser)
Through a capillary tube (
Or expansion valve (TXV)
, Enter the heat exchanger in the cooling space (evaporator)
And then back to the compressor.
In thermal mode, it enters the heat exchanger from the compressor into the heating space (condenser)
Through a capillary tube (or TXV)
, Enter the heat exchanger outside the heating space (evaporator)
And then back to the compressor.
Remember that heat flows out of the evaporator and enters the condenser.
Here is a link to provide a more detailed explanation: This unit uses a capillary tube to limit the refrigerant flow and produce the pressure required to condense the refrigerant.
The TXVs is used by modern devices to adjust the system pressure.
While they are more effective, unless specifically designed for heat pumps, they usually work only when the refrigerant flows in one direction.
A capillary tube is a long and thin tube that has a specific diameter and length to produce a specific pressure.
There are no mechanical components in the capillary, so the refrigerant can flow in two directions.
So in order to make this air conditioner a heat pump, all I need to do is add a check valve and rewire the copper tube.
This is what I did :-
Remove the unit from the trailer roof. -
Get the part number of the compressor and fan motor in order to find a compatible replacement when needed. (I did)-
Measure the diameter of the copper tube so you can use a compatible check valve.
The check valve has different sizes depending on how large the unit it designed.
Try to find the valve in the air conditioner unit with the same size fittings as the copper pipe.
If not, you have to let the adapter increase or decrease the size.
Keep in mind that refrigeration copper is a "pipe", measured on the outer diameter, not a "pipe" measured on the inner diameter ".
Once you get your check valve, you have to figure out where to install it.
My case is that there is enough room for this unit.
I put it on the base and fixed it with a heavy zip tie.
Get some refrigerated copper pipes (whatever size(s)you may need)
And propose a layout.
There will be a label on the check valve to let you know where what went.
The solenoid on the check valve has different voltages.
Make sure your voltage is right (mine was 25VAC).
One thing to remember, you need a bi-
Directional filter.
Install the filter before the compressor intake.
Weld the connections when you are ready to make them permanent.
If you only have one propane torch, you must use the Harris accommodation
Brite 8 silver welding and melting (
Melting at lower temperature).
If you have acetylene or MAPP torch you can use-
Silv brave alloy.
Once you 've welded everything, it's time to get all the air out of the system.
You can get an air conditioning evacuation pump in AutoZone as a lonely tool (This means free! ).
Sometimes the counter rep doesn't even know they have, but it's on a plastic pad with all the loan tools on it.
You also need multi-pipe valves, you may have to buy them, but it doesn't matter, because you will use them on other air conditioners and heat pumps if you can do that.
Connect the pump to one of the service ports and open it.
To get a good vacuum, let it run for about half an hour.
Fill the copper tube with dry inert gas if you want, and then lower it to a vacuum again.
I just dropped it to a vacuum once.
According to the specifications on the equipment, use the refrigerant to replenish the manifold. R-12 and R-
22 is regulated and can only be purchased by technicians.
However, you will be surprised by what you can find on eBay.
You need a thermostat made for a heat pump.
If there is no unused wire, you will also have to run an additional wire from the thermostat to the heat pump.
The heat pump thermostat will signal through this wire to activate the solenoid valve.
When the check valve is reversed, it goes from heating to cooling.
Everything else in the unit is doing the same thing.
I made this change about 18 months ago and so far it works great!
It keeps me cool on 110 degrees and warm on 25 nights! Good Luck!
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