ok i found this pdf "Hyperion* Field Reference Data *TAM7" now i understand the LED better. i was confused about AFC v.s. EVC lights. AFC is flashing 11 meaning problem with EVC, EVC is flashing 10 means problem low superheat.

what are the common causes for low superheat? i measured ohm of the stepper motor on its terminals, supposed to be 46 ohms but I got a reading of 4.4k... i guess the motor is busted?

 

actually problem on my part the motor ohm fine so it is something else. at this point i will just wait for the technician...

 

Multiple things can cause low SH with the main ones being low on air flow or a faulty sensor on the TAM7.

 

yea thanks.

i feel like i don't have the equipment / knowledge to troubleshoot this (probes and gauges for doing sensor / eev valve tests) to be able to pinpoint the issue. will see how it goes with the tech, hope he is good / knowledgeable. but i always like to have a bit understanding of these stuff myself i found it interesting.

by "low on air flow", you mean like a design / setup issue for e.g. return grill not big enough? or maybe something obstructing the air flow in the pipes? i didn't use to have this issue (had this system for a few years) so it should be something new...

 

Could be a lot of things, error codes don’t tell you the problem, just the symptom. Yours is that the refrigerant isn’t picking up enough heat which could be an airflow fault, a refrigeration fault or an electrical fault.

 

so the guy came out, said i was low on refrigerant, really low. so he charged it, now it seems to be cooling better. however those red lights are still on... the guy was like don't worry too much about it... he is going to come back and add dye to see if we can find the leak.

i'm kinda feeling uneasy about the fact that the red lights are still on... should i be worried?

 

Really Low

Did he leak check at all?

I don’t have a problem with dye but that’s the last leak check option in my book!

 

he leak checked outside with his meter around the AC unit found nothing, but didn't check the inside.
i'm unsure if dye will help because i have a finished basement if the leak is in a pipe covered in the ceiling i won't see it... also the dye is expensive...

 

Call the company back and “Request” a more senior tech on the next visit!

 

I’d guesstimate that 95% if leaks will be at the indoor coil, no idea why he didn’t check that? Leak dye is for when your just not finding the leak with an electronic leak detector or soapy bubbles as pecmsg said. As for the led’s, he may not have fully charged the system or you may have a multiple offender. Very unlikely that it’s leaking in the lineset but it’s possible, if you are you’ll start to notice a growing stain in the drywall from refrigerant oil. How long did he spend working on it?

 

no idea why he didn't check leak around the air handler... just to charge more money for the dye probably?
spent about an hour recharging it etc. the idea of having him to check for leak indoor around the air handler did come across my mind i guess i should have asked him to do it...
according to him he did fully charged it up, so i suspect there is still something else wrong in the system...

 

On the red LEDs, it seems like you have to reset them, I don't think they go away on their own.

Low superheat is for example 0-5. High superheat would be 30-40. Superheat is a measure of how much liquid refrigerant is in the indoor coil, so low superheat would mean that the coil is almost full. That is generally not a situation with a low refrigerant charge.

 

yea, that's why when i told him the indicator was showing low superheat he was surprised, and asked if it wasn't high superheat, because from what he was reading from his gauge...

so i think 1 problem is there is a leak somewhere, caused it to be low on refrigerant, hard to not trust his gauge... after he recharged it, the gauges reading are good, and it was blowing out cold air, that's why he told me not to worry about the error LEDs. Maybe there is something else causing the air handler giving high superheat error. maybe the sensors are busted?

Also @BNME8EZ you mention the red LEDs lead to be reset, how do it do it maybe I'll give it a try...

 

just to keep everyone posted, the red LEDs turned itself off - maybe just take some times for it to realize and reset itself (previous i did power cycle it multiple times hoping it will reset to no avail. but this morning i just noticed the error is gone)?

they're still gonna come back for adding dye. they say the dye has a sealant in it if it is a tiny leak it is possible it will seal it...

 

There is no such thing as “Good Gauge Pressures” !

 

sorry i'm not hvac expect, but if he recharged it, and temp and psi good from the gauges, isn't it at least good for now?

 

Checking and charging refrigerant we use subcooling and superheat, not pressures, because it’s blowing cold is not always an indicator of a properly working system. I saw a system last summer that the evap coil and blower wheel were so dirty that the system still had a good split even with a major refrigerant leak. Homeowner only called because her bill seemed high and figured it needed a good cleaning. The TAM7 has very specific diagnostic steps one must take to determine proper operation, you can’t wing it

 

I was hoping he would follow those flow chart i found in the service manual for diagnosis. But I don't think he was particularly familiar with tam7...

where can I find techincian that know trane product. This guy was already from a hvac company I found on trane website but I don't think he was particular familiar with trane...

 

The guy sounds lazy as hell, guessing a/h is in an attic? He needs to leak check the indoor coil, leak dye is for last resort, not to avoid having to leak search. I would not let anyone put in any leak stop kind of product. It will contaminate everything in the system and can cause more problems, personally I won’t install it unless the customer demands it and I get a signature stating that they have been informed I am against doing this. Call the company back and ask them if it’s their policy not to leak check the indoor coil, if they say there’s no need, call someone else