LG mini split code CH45

[keithnellie]

I have a model LMU366HV outdoor unit and a LMAN125HVT, a LMAN180HVT and a LMAN095HVT indoor units. To be more accurate I have 4 sets like this. 

 

A couple weeks ago you guys helped me figure out that my incoming power to my house was the culprit in my washer and dryer not functioning correctly. At the time it was still somewhat cool at night so all my mini splits were still in heat pump mode. Once it warmed up enough to switch them over I did the yearly maintenance of cleaning the coils, changing all the filters and making sure my drain lines were all clean and open. When I turned them back on all but one came up fine and started cooling. The one having the problem is showing a CH45 code. The manual I have says this is a problem with the condenser pipe sensor. It even shows how to check it. My problem is I can't find it. The manual has pictures of everything else but not this connector.

 

Do you guys have any resources that can help me with this? LG won't even talk to me. It's not like I am messing with the R410A. If I need the refrigerant side worked on I have a licensed HVAC guy to do that.

 

I am hoping the problem has something to do with me cleaning the unit as opposed to the excess voltage like the washer and dryer. So far the only thing that cost me any money from the over voltage was my well pump and a toaster. I am still fighting with my utility about them paying for my well pump and don't want to add a outdoor HVAC unit to the list.

[m_west5]

I believe this would be connector 45 on the main pcb in the condensor unit. Note the wire colors and trace it until you find the sensor. It may have fallen off.

If this is the case, measure the resistance of the sensor. If good, then board is bad.

Let's start there while I try to find the manual.

[m_west5]

OK I found the manual.  Shout out and thanks to brothers DA and Spannerwrench.

 

On the main pcb, you will see 3 green capacitors in a horizontal row.  Below these is a single green capacitor directly below the left one in the 3-row.  This is our reference.  Now directly to the left of the 3 row capacitors is a green light and a red light.  Directly to the right of that is a brown 4-pin connector.  Directly BELOW that is a white 4-pin connector.

 

This is CN_TH2.  This is the condensor pipe sensor connector.  It should be printed by the connector on the pcb inlay.

 

Measure:

 

Normal resistance : 5KΩ at 77°F (Unplugged - power off)

Normal voltage : 2.5Vdc at 77°F (Plugged in - power on)

 

The wires you are measuring are either the top 2 or bottom 2.  (?The manual does not give pin numbers? Thanks LG.)  This connector is shared with the ambient air temp sensor mentioned below.

 

If any of these values are bad, sensor is bad.  If the values are good, main pcb is bad.  Depending on ambient temperature, the resistance and voltage readings may be different.  The manual does not say if it is a PTC or NTC sensor.  But readings should be in the ballpark.

 

The sensor is physically mounted to one side of the outdoor coil, perhaps on a pipe.  Just get in there and look.  Trace the CN_TH2 connector wires by color to the condensor pipe sensor.  It may have fallen/broke off where it was mounted. (The other sensor mounted on the opposite side of the coil is for measuring ambient air temp.)

 

You also need to check CN_COM connector (also marked on inlay) to make sure no corrosion, good tight connection, etc. It is the big white connector in the lower right corner to the left of the blue relay.

 

Sorry it won't let me copy the picture to post here but reply if you have any questions.

 

Good luck.

Edited June 1, 2014 by beam current

[keithnellie]

I know exactly where you are talking about and the connector. I will check it as soon as I am off my night shift (12 hour rotating shifts currently on nights for two more days). I appreciate your help. The LG manual I have shows a drawing of checking the connector but the connector they show is a 3 pin connector with only the two outside positions used. I couldn't find anything that looked like that so I had to ask experts.

Many thanks,

I will post the results.

[keithnellie]

The connector has two pairs of wires, blue and black. The black wires go to the ambient temp sensor mounted to the back of the coil outside the unit.The blue wires go to the condenser pipe sensor. The resistance for the condenser pipe sensor measures 88 ohms and the voltage measures .070 vdc or basically nothing. The ambient sensor measures 2.5 vdc and about 11 ohms.

 

Looks like I need a new sensor but I am thinking they probably come as a set unless it is common for techs to carry the fancy tools for making up the pins in the connectors. I actually have some of those fancy tools but not that small.

 

Any ideas where to get the parts?

 

Thanks 

[m_west5]

Awesome job !!!!!

 

Extraction tool:

 

Mouser Electronics.  Little pricey, but good quality stuff.  Radio Shack, worth a shot and they are local.  Do you have Fry's Electronics stores in your area?

 

Think you could do it with a small pick tool to CAREFULLY compress the catches?

 

I'll check on where to get the sensor.  Stand by.....

Edited June 5, 2014 by beam current

[m_west5]

I believe you can order it right here, thru this site.  Use the parts search bar at the top of the homepage.

 

Check this part #: Part number: EBG61107014

.  Is this it?  Several were listed but this has the 4-pin white connector and what looks like the wires are blue/black.  Need to verify against your part.

 

If it is, APP offers a 365 day return policy, even electrical parts, plus you help keep the lights on here.

 

Good job.

Edited June 5, 2014 by Samurai Appliance Repair Man
Added part link.

[keithnellie]

That is it exactly. No need for an extraction tool. I will order the part now. thank you

 

 

[m_west5]

Our pleasure. Let us know how it turns out.

[keithnellie]

Everything worked great for a couple months but now I am getting a ch46 fault code. It seems the suction sensor is now bad. Can I get this sensor from you guys too? 

[m_west5]

Sorry for the delay in replying. Yes, you should be able to order here. Check for a LG part number printed on original harness and do a condenser model # search on app ..... appliance parts pro. (Scroll up).