Liquid Solenoid valve help


  #1  
Old 06-12-08, 06:55 PM
K
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Liquid Solenoid valve help

I have an old (1989!) Kenmore condensor unit that quit on me a few days ago....as it turns out the problem is a liquid solenoid valve that keeps liquid coolant from running back into the compressor. The solenoid is coil is opened so with this valve closed all the coolant is squeezed between the compressor and the closed solenoid...

well...even though this is an OLD unit if I could get it running again that would be great and a the cost of the coil should be pretty low...if I could find it.

I need a replacement coil for the solenoid valve. ANyone know where to find one. Sears doesn't have it anymore..

The part number on the assembly is
ALCO 208-240/50-60
HQ1051491AC
AMF12W

IF I pop the coil out of the bracket there is some additional information on it....
N-1044
X22332-7048

I checked out ALCO's website (now Emerson controls) but was not able to find these old part numbers. I will call them in the morning...but any other help would be appreciated

Thanks
Keith
 
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Old 06-13-08, 04:00 AM
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Try contacting your local Johnstone Supply branch. They are very good at cross referencing, may be able to take care of your problem.
www.johnstonesupply.com
 
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Old 06-13-08, 06:46 AM
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Thanks...but will it work???

Thanks for that....I contacted EmersonClimate and they were able to give me an updated PCN (057540) or AMF240V.
Johnston did not have it but they recommended either United Refrigeration of Sid Harveys.

URI has it but Wont sell it to me becuase I'm not a contractor.

Sid Harveys may be able to get it but they have to get back to me.

So....as I go through this process what are your opinions about whether this valve is going to actually open up when I slip the new coil on it.....it probably has quite a load of pressure sittin on it right now and I am a little concerned that it may not move even with the new coil.

K
 
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Old 06-13-08, 08:27 AM
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Do your homework...
Is the coil indeed bad as you suppose?

If the coil is not the problem, replacing it won't do anything for you.

As for the pressure, that should not be a concern at all. These valves are designed specifically to handle them with no difficulties whatsoever
 
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Old 06-13-08, 09:21 AM
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as the p man says you may just be chasing your tail on this one. How did we come upon this hypothesis about the solenoid valve? Not saying you are wrong it is just a bit unusual to see a bad solenoid, carry on with replacement I am sure the part is cheap enough and replacing it is pretty easy just curious about how this was diagnosed and thinking that this could be valuable information to anyone out there that has a older unit that utilizes a solenoid valve
 
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Old 06-13-08, 09:28 AM
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Guys, the OP said

"The solenoid is coil is opened so with this valve closed.." etc, etc

I think what he meant was "the windings on the coil read an open" ?

Maybe?

Just reading as a non-HVAC tech, but an old Navy electronics tech who had to decipher all sorts on "It quit working" comments.
 
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Old 06-13-08, 09:42 AM
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Ok ole navy dude agreed but lets let the poster explain his method I still think it will be very valuable. heck I would like to know how to check a coil myself. Should you get some ohm readings thru the coil or sumpin?
 
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Old 06-13-08, 09:56 AM
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Well, an open is pretty easy...infinite ohms. Now knowing what the actual value of the coil should be is another thing, but it's pretty low normally.

Had a coil in a radar unit back when I was a "young Navy dude". I thought an ohm or 2 didn't make that much difference. Didn't consider the extremely high freq (5.6 GHz) and the voltage (10 Kv). Well it made the diff between working and not working...

I'd like to know how the OP found it myself. Always adding to the store of knowledge I'll never put to any real use...lol
 
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Old 06-13-08, 10:05 AM
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I think that his breaker is tripped and that is causing the problem. Why are you not going to utilize all the information that you have gathered Gunny?
 
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Old 06-13-08, 10:12 AM
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Guys, you two crack me up...
 
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Old 06-13-08, 10:47 AM
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Pflor, anything ta give you a chuckle.

BTW after the help you gave me before, the furnace-A/C is workin like a champ. Fans run when supposed to, and the house is much more comfy. Important out here, already a couple of over 100 days. The wife (She Who Must Be Obeyed) is very happy.
Still need to get up and straighten the fins on the condenser coil, and oil the motors. Course, then it'll prob crap out completely, 2 days after the home warranty is out.

Former...too old to be getting my certification. And no money to buy all the stuff required anyway. lol
Some I'll use though, maybe Jeopardy or the Cash Cab will come here and have a DIY question category.

Oh, and don't let any Marines see you call me Gunny, tho I was a Chief..sooooo.
 
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Old 06-13-08, 11:19 AM
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Opened...I did mean no continuity

Thanks for all the comments....I am happy to see so much activity!

Tested the coil with and Ohm meter....I don't remember the reading but it the wire was clearly broken somewhere...a coil shouldn't show more than a couple of Ohms.

With that valve closed the refrigerant all got sucked into the condensor...this made the compressor heat up and stress out! It started drawing more and more till the breaker popped.....at least that is what we think happened.

The breaker ultimately failed and it started to break at 12 Amps.....so first order of business was to replace that....Done.

Now the unit starts up but sounds pretty bad...because of all the pressure.

I found the coil at Sid Harvey...I should have it in a day or so. I am happy to see the reassurance that the switch should open once I get some EMF on with a fresh coil.

I just hope we didn't to any damage to the compressor with all of this but I guess I'll find out.

I have to say...it sounds like a pretty DUMB design to put the valve on this side of the Fill port (or whatever you call it) one has to believe that a failure is possible. If I couldn't free up that valve then I have a condensor stuffed with refrigerant and no way to evacuate it except some sort of rigged up saddle valve or something.

Keith
 
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Old 06-13-08, 11:45 AM
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Actually, what you have there is a pretty smart design...really!

With the solenoid in the liquid line, your system goes thru an automatic pump down each and every time a call for cooling is satisfied. Pumping down means (as you correctly stated) that the entire charge of refrigerant is sent to the condenser.

At any rate, when you have a circuit arrangement such as this, the condensing unit must have a switch called the "Low Pressure Cutout", which is wired in series with the compressor's contactor.

On a call for cooling, the t-stat actually talks to the solenoid coil only, not the contactor coil (which remains de-energized for the time being, keeping the compressor OFF)...with the solenoid coil energized, its port opens, and high pressure liquid from the bottom of the condenser starts moving down the liquid line (which is empty hence at a lower pressure --> high pressure goes to low pressure), continues on thru the expansion device, in and thru the evap and finally thru the suction line (now already as a gas, after having gone thru the evap)...the pressure sensing element of the cutout switch is located on the suction line...as pressure increases there (and this takes just a few seconds after the solenoid was energized), the contacts of the switch close, juicing up the compressor. The system is now up and running.

Once the call for cooling satisfied, the t-stat de-energizes the solenoid and its valve port closes (the compressor continues running)...since refrigerant flow is not interrupted, with the compressor running, refrigerant will be progressively emptied out from the liquid line and evap and dumped into the condenser, which will turn it into a liquid (hence keeping the pressures in check)...as the low side of the system becomes emptier, its pressures drop, to the point which will force the contacts of the cutout switch to open up, shutting OFF the compressor.

Pretty cool, huh?
And all this process, what for?
Well, for once, keeping refrigerant off the suction line will prevent refrigerant migration to the compressor during cold weather, which is a killer of compressors (slugging).
In refrigeration is used prior to a defrost cycle, to avoid excessive evaporator (and suction line) pressures once the defrost cycle is completed.
 
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Old 06-13-08, 02:53 PM
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Good explanation of a pump down cycle.
There is another way to use a solenoid on a liquid line and the scheme is called a "solenoid drop".

The solenoid in this case would be connected to energize with the compressor contactor either across the load terminals of the contactor or with 24 volts from the contactor coil.
This solenoid would prevent liquid refrigerant migration to the compressor during the off cycle when the outdoor temp is much lower that the evaporator temp as pflor has explained.

To know if you have this system you will find that the wires from the solenoid coil are connected to the same terminals on the contactor as the compressor and the thermostat directly energizes the contactor.

I have never seen a pump down on residential a/c.
We are talking a/c aren't we?

As far as dealing with a bad solenoid beyond the coil a certified a/c mechanic would have to reclaim the refrigerant and replace the valve.
 
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Old 10-21-08, 04:07 AM
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Liquid Solenoid Valve-Follow up

I just thought I would post a follow up, months later, but there were so many good comments I thought I would close out the thread.

I found the replacement coil, Sid Harveys was actually willing to sell the part to me. dropped it on the valve, hooked it up and everything went back to normal right away.

Thanks for your comments!

K
 
 

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