I don't see many of these anymore

This is for the newbies why is this valve in the liquid freon line to the A-coil and what controls it???

The second pic almost got me I was fishing for the cord to the condensate pump and came up with Harry’s substitute for a electrical outlet first off I thought the pump might have been 24 volts so I checked the voltage with a meter and came up with 120 volts on a low voltage wire :frowning:

Is it part of a heat reclaim system?

No sir its not its strictly part of the refrigerant system in the cooling mode only

Darn! I will research after dinner if no one else knows.

It is felt they are no longer needed because we now have scroll compressors…

I have shocking news…

Does that mean we can now legally operate the A/C unit when the ambient is below 60 degrees:twisted:

Low ambient temp kit.

No again but you are at least thinking I would be thinking more along the lines of high ambient. Its not a kit its just a 24 volt valve and has a singular purpose

Maybe I should call my HVAC tech lol. I do enjoy the mind stimulation gonna look a little more. Now I’m thinking maybe something for high humidity.

Ok last try.

Defrost pump down solenoid valve.

Must be a northern thing whatever it is never seen one around here.

Nope not a northern thing it could be anywhere but it is a pump down solenoid valve but nothing to do with a defrost on a heat pump. It is opened and closed by the thermostat the pump down system must also have a low pressure switch that controls the on and off of the compressor. A pump down system makes it easier for a compressor to start as the compressor does not have to start against a high head pressure;-)

Ahh makes sense now. So the compressor must be a piston type much like an air compressor that releases air when it shuts off to make it easier to start. Thanks Charley.

This is most needed when the compressor and evaporator are at significantly different elevations, or excessive line set length requiring additional refrigerant in the circuit.

The compressor high side pumps a vapor. When liquid refrigerant can migrate to the compressor or flood the evaporator it keeps this separated.

It also has to do with the type of TXV that the system uses. If it is not an equalizing TXV (commonly an older style - design), the liquid refrigerant backs up on the compressor. The change of state causes excessive pressure for the compressor to deal with.

Ken, a pump daown is used in refrigration defrost cycles like you are talking about. When a freezer defrost heater comes on, it adds too much heat-pressure to the compressor when it comes out of defrost. Also a pressure regulator can be used to control the amperage draw and overload of the compressor.

Refrigeration and air conditioning are not the same animal however.

Liquid line solenoid increases the efficiency by (as I recall) .4 SEER so we were told.
I installed quite a few of them years ago as part of Coleman’s highest efficiency air-conditioning systems at the time.
Like was said, it cycles off and on with the condensing unit.

Coleman’s had nothing to do with “different elevations, or excessive line set length”

I still have one one my house although I have replaced both the high side unit and the gas furnace and kept the A-coil along with the solenoid valve.

I guess that is why we don’t see too many Coleman units out there…

The payback on 0.4 SEER / 6 months hardly covers the cost of the silver solder to install the thing. Never mind pay for the valve.

As you know pump down systems on residential units [Carrier mostly] was a carry over from commercial where the walk ins or open display cases were a great distance from the condensing unit. I installed many in that fashion;-)