GDM-10 not cooling

[ectofix]

How deep of a vaccum did you pull?

Did it hold that vacuum for some reasonable period of time to ensure there’s no leak?

After you charged it, what were your pressures?

Did you replaced the drier?

Is it a cap tube or TEV system?

What’s the ambient temp?

[olivero]

Does the evaporator have to freeze over?

 

IT just has to blow cold air, is it doing that?

 

What does “serviced” entail?

 

Why did you do anything to it in the first place, lot of missing information.

[fixbear]

You have given us a minimal of information.  However I can tell you that the compressor is not loading up with that low of a amp draw.  Should be about 4.4 amps full load.  So you must either be in a vacuum on the suction side (1) or have a broken valve in the compressor (2).  

 

1;  Low charge, (Often from a small connection leak at charging).  blockage with liquid supply like drier or cap tube. causing very low suction pressure.  Cap tube insertion into the drier before brazing is critical.  to deep causes flow restriction from hitting the screen,  to shallow may cause braze restriction.  Then there is oil contamination.  R134 has to have polyester oil. if a small amount of mineral from say gauges used on a older system is introduced, it will form a slug.  Then there is always the possibility of a small amount of moisture. Rain day’s and high humidity are always a problem. It will accumulate as ice at the point in the cap tube where the liquid first starts to form vapor  Seen many a cap tube replaced unnecessarily due to this.  Before 4 valve charging manifolds this was very common.

 

2;  Broken valves are usually caused by a liquid slug during charging.  But can also be metal fatigue.  I’ve also seen improper piping where the suction line was the coolest part of the system at start-up.  Causing a cylinder head blow out.

 

Before going crazy on this, place your ammeter om the compressor and add a small amount of refrigerant as you watch the suction pressure. If amps come up, compressor is ok.   Running suction pressure should be 15 to 20 degrees below the evaporator temp.  At the same time, monitor the high side compressor discharge. either temp or pressure to make sure you don’t overload it.

[bwoodyb]

Thanks for the quick response. I’m fairly new to this field, so please bear with me. I do think that the compressor is bad, but I’ll try adding refrigerant slowly and checking the amp draw.Here are the steps that I did.1.Depleted the system and pulled a vacuum for about 30 minutes.a), Disconnected…..system held vacuum for 30 minutes, so I disconnected to begin adding the refrigerant2.Slowly charged system with 10 oz 134A ….based on the placard.3. Connected suction line to service port and monitored pressure. Suction pressure was 5 psig. I didn’t have the high side connected. Compressor amp draw (1.5)4, The evaporator never got cold and the condenser never got warm.5. I thought about a clogged filter, but it was never warm on the inlet side of the filter. I don’t think the compressor is moving refrigerant. I figured that if I was getting an amp draw that it was working. Didn’t know that it could happen and still have a bad compressor.

Thanks for the information. I’ll try adding refrigerant and monitor the amp draw.

    On Thursday, April 11, 2019 07:47:29 AM CDT, fixbear <root@flph837.prodigy.net> wrote: 

 

  #yiv7993547941 * #yiv7993547941 a #yiv7993547941 body {font-family:Helvetica, Arial, sans-serif;}#yiv7993547941 #yiv7993547941 h1, #yiv7993547941 h2, #yiv7993547941 h3, #yiv7993547941 h4, #yiv7993547941 h5, #yiv7993547941 h6, #yiv7993547941 p, #yiv7993547941 hr {}#yiv7993547941 .yiv7993547941button td {}

|

 

  TechTOWN 

 

 

 

|

Re: GDM-10 not cooling

 

reply from fixbear in Most Recent Questions – View the full discussion

 

You have given us a minimal of information.  However I can tell you that the compressor is not loading up with that low of a amp draw.  Should be about 4.4 amps full load.  So you must either be in a vacuum on the suction side (1) or have a broken valve in the compressor (2).  

 

 

 

1;  Low charge, (Often from a small connection leak at charging).  blockage with liquid supply like drier or cap tube. causing very low suction pressure.  Cap tube insertion into the drier before brazing is critical.  to deep causes flow restriction from hitting the screen,  to shallow may cause braze restriction.  Then there is oil contamination.  R134 has to have polyester oil. if a small amount of mineral from say gauges used on a older system is introduced, it will form a slug.  Then there is always the possibility of a small amount of moisture. Rain day’s and high humidity are always a problem. It will accumulate as ice at the point in the cap tube where the liquid first starts to form vapor  Seen many a cap tube replaced unnecessarily due to this.  Before 4 valve charging manifolds this was very common.

 

 

 

2;  Broken valves are usually caused by a liquid slug during charging.  But can also be metal fatigue.  I’ve also seen improper piping where the suction line was the coolest part of the system at start-up.  Causing a cylinder head blow out.

 

 

 

Before going crazy on this, place your ammeter om the compressor and add a small amount of refrigerant as you watch the suction pressure. If amps come up, compressor is ok.   Running suction pressure should be 15 to 20 degrees below the evaporator temp.  At the same time, monitor the high side compressor discharge. either temp or pressure to make sure you don’t overload it.

 

Reply to this message by replying to this email, or go to the message on TechTOWN

Start a new discussion in Most Recent Questions by email or at TechTOWN

Following Re: GDM-10 not cooling in these streams: Inbox

 

 

This email was sent by TechTOWN because you are a registered user.

You may unsubscribe instantly from TechTOWN, or adjust email frequency in your email preferences

   

 

 

 

[fixbear]

You don’t have to tap the high side to have some idea of what it is doing. Clamp a thermistor on the high side line. you can then check the temp pressure chart to come close to high side pressure. Temp will be about 20F than actual pressure. 

 

With vacating and recharging,  One should never disconnect your gauges till the system is positive pressure.  It can be done with a 3 valve, but one has to make sure to bleed the yellow hose at the manifold before charging.  Then you can start to measure the charge.  Being you had a 5 psi after charging, the compressor was pumping.  Otherwise the system would read the equivalent or ambient temp pressure.

 

Vacating today is not done with time, but a good Micron gauge.  Vacate to below 700 micros.  If your in freezing temp’s, go to 400 microns. It is also used to verify how good your connections and pump are. You will have to change the vacuum pump oil monthly to maintain it’s ability to pull a deep vacuum.

 

The 1.5 amp draw is idle for the motor. Nothing to move due to the low suction pressure.  As you add refrigerant it should rise.  And the high side/ compressor discharge will get hotter.  Then the top of the evaporator will get warm.  And you should start to feel heat rejection from the cooling fan air flow.

 

The best reference to learn and understand this is a text book called modern refrigeration.  Often you can find it at a United store. It’s a source that I still to this day use for reference. Though a lot newer version than my first one.  Joining RSES and making use of there monthly meetings and training is also a great benefit.  You can also pull from other members and CMC’s in your area for help when you get into a bad one. Your local refrigeration supply houses can tell you if there is a chapter near you.

[fixbear]

By the way, the smaller the system,  the more sensitive it is and a pain in the butt.  A 10 cubic foot machine only uses a 1/5 hp compressor like a home refrigerator has.