AC pressure readings and problem with dealer.

[Doug580l]

In both of these deals if every one has proof that they have a problem and tryed to get it fixed then at the end of the day they could get a lawyer and try to sue but i dont know what he gave for the car it could have easly been worth alot if it was only a year old. But going to court the good guy dosent always come out the winner. I have been there before and court isnt always about write and wrong its who is lucky and has a good lawyer.
I have made alot of mistakes in my life and its easy to point out when others make mistakes my brother made a mistake and Doug5801 has to they should have never left the lot until they thought the problem was fixed.

The first machine was sent back without anyone contacting me. On the second service I told them I wanted to talk to them before sending the machine back. Talked to the service guy and he said they found a clogged drain, did a few other things and it's working better now. I asked him about the pressure readings and he said they were normal now.

 

[Doug580l]

To hell with trying to get them to fix it. The amount of down time , I would just put the new thermostat switch in it and move on. I thing this thread has let you know what is wrong with it. The ac cools till the core freezes. Then will work agaiin briefly after it melts. If you could see the evaporator corre when it quits cooling it would look like a block of ice , not just frost. The thermostat typically has a capillary tube that stick in the fins of the evaporator. It cuts the compressure off to keep the core from freezing.

The thermostat on this machine is an "electronic deicing thermostat". I would be fine replacing it but it's tucked away in a hard to get to place and the service manual says to make sure to reinstall it in the same location or it could effect the ac performance. Unfortunately the manual has a crappy little black and white picture that is no help regarding the exact location.

 

[Doug580l]

I want to say thank you to everyone here taking the time to help. Thanks to you guys I can sound a little more intelligent when I talk to the dealer. You've definitely put in more effort than them.

I talked to service yesterday. They are going to look at the machine again next week. They said that they did remove the valve at the end of 1 of the drain tubes because they are prone to clogging. They also drained and refilled the freon with dye in it to check for leaks.

I asked him if they checked the thermostat or the expansion valve or the compressor. Answer is no because they didn't throw any codes. I did a quick search of all the codes listed in the service manual and didn't see any relating to the any of them. I'll check again to be sure.

He said that when they sent it back last time it would get down to about 54 degrees at the vent. He also said that they have a brand new machine there that they checked and that it only got down to 50. I said I have a new machine too and it's closer to 60 and the pressures are still off from the service manual.

I said that they should start replacing some components if the can't get it to work right. Also told him that the last time I ran it, over a 45 minute period the vent temps varied between 48 and 64 degrees at max fan and coldest setting. After that point it was more consistent and stayed between 58 and 62 and that after a while water starts coming out of a couple of the vents. Also told him that I checked the air temperature inside the machine on the opposite side of the vents. When it was 85 degrees out the best the machine could do was about 82 inside. When it was 95 out, it was a little over 90 degrees inside.

He said that he has been in contact with Bobcat about it and opened up a case during the last service about it.

 

[Doug580l]

I think before I dove too deep into it, I would be checking vent temps of other machines that are new or newly new to make sure that's just not how they are. While it may not seem good enough, if that's how they are made your issue isn't with the dealer at all.

I made a post on the compact excavators forum trying to find someone with a machine that could check his temps but haven't heard from anyone yet. My wife contacted some youtube guy who has a bobcat and lives in the general area. She didn't ask about vent temps, but the guy said that the machine's ac has no problem keeping it comfortable in hot temps.

 

[fastline]

Before the machine was brought in the first time, I added about 8oz. of refrigerant to it. It made no change to the pressure readings.

I do realize, which is why one of my thoughts was a compressor issue. I personally don't see them actually bad very often unless people have been in the system. Amazing how that works! They have now been in it now. I am not really convinced it is bad, but data is pointing me there.

I hope you read what I posted earlier. It will probably do little good as I bet the techs don't even know what subcooling is. I am just frustrated FOR you....

The reality is I could be connected to that system and collecting all the vitals at the OEM spec charge. Then add and monitor my values. I think the dealer is scared to add refrigerant because they don't understand them, and I am still sort of wondering if that little guy needs more juice.

One thing you said is vent temp hunts around. That is an indication of compressor cycling or low refrigerant typically as the TXV will hunt around based on what it is being fed.

If you want something very simple to check, if it is super hot both inside and outside the machine and you run that AC, see if the compressor cycles (clutch kicks out). It should NOT.

At some point.... Looking at the head pressure, say it is holding at 170, add a full 12oz can of juice! If it can take that and the head pressure does not budge, time to look real hard at that compressor. Some of them have an internal relief valve to keep from being a grenade, and possible that is bad.

 

[Welder Dave]

I want to say thank you to everyone here taking the time to help. Thanks to you guys I can sound a little more intelligent when I talk to the dealer. You've definitely put in more effort than them.

I talked to service yesterday. They are going to look at the machine again next week. They said that they did remove the valve at the end of 1 of the drain tubes because they are prone to clogging. They also drained and refilled the freon with dye in it to check for leaks.

I asked him if they checked the thermostat or the expansion valve or the compressor. Answer is no because they didn't throw any codes. I did a quick search of all the codes listed in the service manual and didn't see any relating to the any of them. I'll check again to be sure.

He said that when they sent it back last time it would get down to about 54 degrees at the vent. He also said that they have a brand new machine there that they checked and that it only got down to 50. I said I have a new machine too and it's closer to 60 and the pressures are still off from the service manual.

I said that they should start replacing some components if the can't get it to work right. Also told him that the last time I ran it, over a 45 minute period the vent temps varied between 48 and 64 degrees at max fan and coldest setting. After that point it was more consistent and stayed between 58 and 62 and that after a while water starts coming out of a couple of the vents. Also told him that I checked the air temperature inside the machine on the opposite side of the vents. When it was 85 degrees out the best the machine could do was about 82 inside. When it was 95 out, it was a little over 90 degrees inside.

He said that he has been in contact with Bobcat about it and opened up a case during the last service about it.

It sounds like someone at the dealer is trying to help you, maybe the service manager, but on the other hand someone is trying to blow you off, maybe the manager? It was brought up in another thread a while ago that some dealers don't like to do warranty work because it doesn't pay as much as regular service work.

 

[heymccall]

So, you added 8oz to a 30oz system on a 100hr machine?
You added 25% more refrigerant and the gauges still read the same?
Something's rotten in Denmark here...as I've never added and not seen at least a miniscule change in pressure on at least the high side. And, most certainly, on the static pressure.

 

[Doug580l]

I do realize, which is why one of my thoughts was a compressor issue. I personally don't see them actually bad very often unless people have been in the system. Amazing how that works! They have now been in it now. I am not really convinced it is bad, but data is pointing me there.

I hope you read what I posted earlier. It will probably do little good as I bet the techs don't even know what subcooling is. I am just frustrated FOR you....

The reality is I could be connected to that system and collecting all the vitals at the OEM spec charge. Then add and monitor my values. I think the dealer is scared to add refrigerant because they don't understand them, and I am still sort of wondering if that little guy needs more juice.

One thing you said is vent temp hunts around. That is an indication of compressor cycling or low refrigerant typically as the TXV will hunt around based on what it is being fed.

If you want something very simple to check, if it is super hot both inside and outside the machine and you run that AC, see if the compressor cycles (clutch kicks out). It should NOT.

At some point.... Looking at the head pressure, say it is holding at 170, add a full 12oz can of juice! If it can take that and the head pressure does not budge, time to look real hard at that compressor. Some of them have an internal relief valve to keep from being a grenade, and possible that is bad.

Thanks, I did read your earlier posts. Can't say that I understand them, lol but I will ask them about subcoling. I will check for the cycling when it gets hot out again. I have a 1 minute video on my phone of the gauges after I got the machine back the second time showing the pressures and it cycling once. Haven't been able to figure out how to post it. Also don't know if that would help make a diagnosis or not.

 

[Doug580l]

It sounds like someone at the dealer is trying to help you, maybe the service manager, but on the other hand someone is trying to blow you off, maybe the manager? It was brought up in another thread a while ago that some dealers don't like to do warranty work because it doesn't pay as much as regular service work.

It's the same person, the service manager. The first time the machine went in the communication was through the salesman and that caused some miscommunication. He is the one who is bringing the machine back and forth to the dealer. I was expecting to talk to the service guy before they brought the machine back, but it was brought back without contacting me. I called him before it was brought in the second time. I had to discuss/argue with him for about 10 minutes before he agreed to look at it again. Didn't need to argue with him yesterday about them looking at it again, but I think we both still have different ideas of what outcome is acceptable.

 

[fastline]

Thanks, I did read your earlier posts. Can't say that I understand them, lol but I will ask them about subcoling. I will check for the cycling when it gets hot out again. I have a 1 minute video on my phone of the gauges after I got the machine back the second time showing the pressures and it cycling once. Haven't been able to figure out how to post it. Also don't know if that would help make a diagnosis or not.

I'm 99% sure they won't understand subcool, and it is just another diagnostic tool. This is why I am trying to revert back to other ways to find the issue.

You can just explain what the gauges did in your vid. Was the head pressure stable? What was it? What was suction doing? Dropping, stable? What pressure?

 

[Doug580l]

So, you added 8oz to a 30oz system on a 100hr machine?
You added 25% more refrigerant and the gauges still read the same?
Something's rotten in Denmark here...as I've never added and not seen at least a miniscule change in pressure on at least the high side. And, most certainly, on the static pressure.

Yup, the system actually calls for a little less. 1.7lbs or 27.2 oz. I asked the service guy about this and he had no answer, except to tell me that I shouldn't of added any and that I could damage the compressor.

 

[Doug580l]

I'm 99% sure they won't understand subcool, and it is just another diagnostic tool. This is why I am trying to revert back to other ways to find the issue.

You can just explain what the gauges did in your vid. Was the head pressure stable? What was it? What was suction doing? Dropping, stable? What pressure?

Pressures were very steady at 20 and about 160. I'm not sure how long they were steady before the compressor kicked on but it was at least 20 seconds. Then the low side went up to about 48 and the high side down to about 110 and the compressor kicked back on and the low side went to about 20 again and the high side to about 175. I did this video on the day I got the machine back the second time so I didn't time to see how long between cycles.

 

[fastline]

Pressures were very steady at 20 and about 160. I'm not sure how long they were steady before the compressor kicked on but it was at least 20 seconds. Then the low side went up to about 48 and the high side down to about 110 and the compressor kicked back on and the low side went to about 20 again and the high side to about 175. I did this video on the day I got the machine back the second time so I didn't time to see how long between cycles.

If your outdoor temp was 95 or above, you should have had head pressures similar to my first post here with pics of my system data.

My experience is leading me to low charge or bad compressor. The more data that is collected, the easier to pinpoint the issue!

As well, you really need to check the drive belt for the compressor to rule that out. If it has an auto tensioner, that's a quick deal.

Another check is to see if there is response between idle and full throttle on head pressure. There should be, the pump is running faster. If not, that is more intel. I'd like to know what compressor it has. Make and model.

 

[Doug580l]

If your outdoor temp was 95 or above, you should have had head pressures similar to my first post here with pics of my system data.

My experience is leading me to low charge or bad compressor. The more data that is collected, the easier to pinpoint the issue!

As well, you really need to check the drive belt for the compressor to rule that out. If it has an auto tensioner, that's a quick deal.

Another check is to see if there is response between idle and full throttle on head pressure. There should be, the pump is running faster. If not, that is more intel. I'd like to know what compressor it has. Make and model.

I think the temperature was in the mid 80's when I took the video. One thing that I have noticed is that there is very little , if any difference in the high or low pressures whether it is checked at 80 or 95 degrees. I will check and verify that in the next few days. I will also check for the differences at idle and full throttle.

There is an auto tensioner on the belt.

 

[Doug580l]

If your outdoor temp was 95 or above, you should have had head pressures similar to my first post here with pics of my system data.

My experience is leading me to low charge or bad compressor. The more data that is collected, the easier to pinpoint the issue!

As well, you really need to check the drive belt for the compressor to rule that out. If it has an auto tensioner, that's a quick deal.

Another check is to see if there is response between idle and full throttle on head pressure. There should be, the pump is running faster. If not, that is more intel. I'd like to know what compressor it has. Make and model.

I can't see much of the compressor but it is a model no. QP1812 and maybe the brand is TCCI?

 

[fastline]

http://www.valeocompressors.com/media/brochures/TM08-16_servicemanual.pdf

You might try to confirm, but it appears the TM13 might be common for Bobcat. Review pg 10, part 26, relief valve. If I am right, block all airflow to the condenser with cardboard while monitoring head pressure. Even better if it is 95F+ outside. If head pressure refuses to increase, a compressor issue is likely.

Again....man, I would want to monitor subcool here, or more importantly, the liquid line temp because that can be very telling.

 

[Doug580l]

http://www.valeocompressors.com/media/brochures/TM08-16_servicemanual.pdf

You might try to confirm, but it appears the TM13 might be common for Bobcat. Review pg 10, part 26, relief valve. If I am right, block all airflow to the condenser with cardboard while monitoring head pressure. Even better if it is 95F+ outside. If head pressure refuses to increase, a compressor issue is likely.

Again....man, I would want to monitor subcool here, or more importantly, the liquid line temp because that can be very telling.

OK, try to bear with me. I'm trying to understand what you're saying. I know that the low pressure is the suction line and the high pressure is the liquid line. Where do I check the temperatures at? By the connectors where I hook up the gauges?

 

[fastline]

OK, try to bear with me. I'm trying to understand what you're saying. I know that the low pressure is the suction line and the high pressure is the liquid line. Where do I check the temperatures at? By the connectors where I hook up the gauges?

The line temp would be measured after the condenser. There will be lines going into/out of the receiver. That is a good place to gather the temps. I prefer after the receiver as it gets me real world data going to the TXV.

if you reference my image, you will see my line temp was about 126F, and ambient was 100F. Do NOT test with a stupid IR gun. You need a good thermocouple ziptied to the liquid line. You would read the temp at the same time as the pressure. Subcool can then be calculated from there.

 

[Doug580l]

The line temp would be measured after the condenser. There will be lines going into/out of the receiver. That is a good place to gather the temps. I prefer after the receiver as it gets me real world data going to the TXV.

if you reference my image, you will see my line temp was about 126F, and ambient was 100F. Do NOT test with a stupid IR gun. You need a good thermocouple ziptied to the liquid line. You would read the temp at the same time as the pressure. Subcool can then be calculated from there.[/QUOTE
Thanks, I'll let you know the results when I check it. I really appreciate the help.

 

[Doug580l]

The line temp would be measured after the condenser. There will be lines going into/out of the receiver. That is a good place to gather the temps. I prefer after the receiver as it gets me real world data going to the TXV.

if you reference my image, you will see my line temp was about 126F, and ambient was 100F. Do NOT test with a stupid IR gun. You need a good thermocouple ziptied to the liquid line. You would read the temp at the same time as the pressure. Subcool can then be calculated from there.

I did the tests. I checked the readings every 5 minutes or so. I'll give you some of the data and if you need more I might have it. Unfortunately I can't say that I'm 100% sure about the liquid line temps. I got almost the same readings from a very good digital meat thermometer and I used an infrared too just to compare. Either way, it was warm to the touch at the drier but not hot. Highest reading I got was 110. After re-reading what you said, I thought that I was supposed to check after the drier where there isn't any room to hook up a probe. I think you're saying that it can be before the drier. I can try again tomorrow.

Both the low and high pressures generally varied by a few psi every few seconds each cycle so I am giving the middle numbers.

At startup the outside temp was 93 and it was 139 inside the machine.

For the first couple of minutes, the low pressure was about 28psi and high was about 200psi.

After 15 minutes the low was 21psi, high 178psi, vent temp 54, liquid line 110

After about 18 minutes the compressor turned off for the first time. After that it cycled every minute or so.

After 25 minutes low 20psi, high 175 psi, vent 55, liq line 109

After 45 minutes low 19psi, high 163 psi, vent 50-but quickly went up to 58 while cycling, liq line 108.

There was very little water dripping out of the 2 drains that I can see. There is 1 drain that I can't see. The one that still has the valve on it drips about every 14 seconds. I did not see any water coming out of the drain with the missing valve until I turned off the blower and a lot of water came out immediately. Also, by the end there was water coming out of a couple of the vents again. Hope all of this means something and let me know if I need to do some more tests.

Thanks