TRANE RTU---Need help

[the_apprentice]

Hello everyone,
I am brand new and this is my first post, I am trying to impress my boss by hunting down the answer to our problem. We got called to a job today with a "no heat" call on the 1st floor. We went to the roof and found that the RTU was not working, we popped the electrical door and the unit fired right up. We then powered it down to run some volt checks(we turned the power off). After doing our tests, we went to turn the unit back on but got no power at the on/off lever. We would've easily been able to diagnose the problem but we found NO electrical diagrams of where the power was starting and ending. I wrote down the serial and model numbers and was hoping maybe someone could help me out and email me the diagnostic charts(if you have them), I tried calling the TRANE rep in town, he said go online which I did and still no help. The unit is probably 20+ years older. So here are the serial and model numbers:

model # SFHB2006HJ20F22DC5T
serial # J87F81770

Thanks so much for your help!!!!!

Troy(the_apprentice)

[dandyme]

this is a joke, right?????????????????

[timebuilder]

Troy, is that electrical lever attached to a gray box on the side of the unit? Is the lever red?

[jpnova70]

Check the MCC panels.

John

[the_apprentice]

Troy, is that electrical lever attached to a gray box on the side of the unit? Is the lever red?

Hi there,
The lever is attached to a gray box on the side but it is black not red.

[the_apprentice]

this is a joke, right?????????????????

No it's not a joke!!! I'm a new apprentice looking for help, apparently your one of those guys in the field that cant help or train the new guys coming into the proffesion!! Why even respond to the thread if your just going to be an idiot about it? I don't know the answer thats why im asking.

[dandyme]

it might help some smarta@@ keep from getting killed.


FUNDAMENTALS

you get a meter and understand how to use it.


that's how YOU get old enough to think your question is a joke


might want to thicken your skin too


get your panties out of a wad

[jpnova70]

Every commercial bldng. that ive been in has a Master Control Center. This is where the main feeds come in and gets distributed to the equipment before the equipment knife switch or disconect at the unit. Some over loads are at this panel. Now you need to find your overload or cause of failure. Did you take any amperage readings on start up at the disconect? L1 2or 3?Faulty wiring,breaker,fuse?

John

[Paul Bee]

Doesn't calling someone names say a lot about a person? We do not want to see someone injured or dead doing something they are ill equipped for. Take what you need and leave the rest. I believe Timebuilder with 4100+ posts was trying to help you, why not focus on the positive support you are getting here? Rule nuber ONE leave your emotions at home and approach repair opportunities calmly and logically.

[stevehvac]

I have to agree with the others. Your questions are so general that it is dangerous to answer. If you lost power to the units main disconnect then you have a tripped breaker (if your are reading the meter correctly). Anyone with basic knowledge should know that power comes from down in the eletrcial panel and not in the unit. Electrical diagrams are nice but after 2-4 years most of them become unreadable.You will have to learn to trace out wires yourself. A meter is your best friend. The good news is usually a problem that trips the main is easy to find.

[ascj]

Hello everyone,
I am brand new and this is my first post, I am trying to impress my boss by hunting down the answer to our problem. We got called to a job today with a "no heat" call on the 1st floor.Who is we?
We went to the roof and found that the RTU was not working, we popped the electrical door and the unit fired right up.How did you pop the door without turning the dissconnect off?
We then powered it down to run some volt checks(we turned the power off).How do you do voltage tests, with no power
After doing our tests, we went to turn the unit back on but got no power at the on/off lever.You had no voltage at the disconnect, on the load or line side?
We would've easily been able to diagnose the problem but we found NO electrical diagrams of where the power was starting and ending. The wiring schematic won't be much help, if you are only at the disconnect.
I wrote down the serial and model numbers and was hoping maybe someone could help me out and email me the diagnostic charts(if you have them), I tried calling the TRANE rep in town, he said go online which I did and still no help. The unit is probably 20+ years older. So here are the serial and model numbers:

model # SFHB2006HJ20F22DC5T
serial # J87F81770

Thanks so much for your help!!!!!

Troy(the_apprentice)

You keep saying "WE". Your an apprentice, so you had a senior or journeyman tech with you? What did he say?

If you need the schematic, just shoot me a PM.

[StayinCool]

Hi guys!...Wow a lot of professional members in response to this apprentices query. Some I'm fairly new to the post but not to hvac. For The_apprentice one very important thing Ive observed here is that most of the seasoned journey-people here offer very good advice and insight. Listening here is the best tool! As you are new to this trade your Boss should not have huge expectations in your technical and mechanical ability. And you should always be supervised by someone for a while, especially with electricity. 24v can Kill you under the right circumstances. Realistically a .5 amp across your heart will do it. Thats Nothing. Not to mention that you were likely messing with either 208/230 or 460vac! You should really take heed and get a basic electricity class and schematic diagram class. If you have a good boss, that should impress him. He might even pay for it.

[jayguy]

...For The_apprentice one very important thing Ive observed here is that most of the seasoned journey-people here offer very good advice and insight...

but they are not offering much advice or insight on this post.

with respect to those seasoned journey-persons, while not being very kind, they are correct in their intention of keeping the apprentice ALIVE.

the apprentice: i admire your intentions. perhaps what ACTUALLY happened is not exactly how you described it or how everyone here interpreted it. it is difficult to ignore the jabs and name calling...but try to see through them to the real intention of helping and not being able to communicate it very well...or ignore them completely! spend much of your time in reading the posts and learn from these people. you are probably not going to ever impress your boss (at least at this point) with finding the answer to a particular problem, however, you can certainly impress your boss by your dedication to learning...let him/her know what you are learning.



oh, and welcome!

[John Culpepper]

This is just my 2 cents worth. Be careful with electricity, it'll kill you. That being said, you need to check the voltage on the line side of your disconnect to determine wheather or not you have correct power to your unit. If you don't you will have to track the wiring back to the next source of power. It will probably be a breaker in an electrical room. Good luck, learning this trade can be adventuresome.
http://i256.photobucket.com/albums/hh169/JohnCulpepper/100_4433.jpg
http://i256.photobucket.com/albums/hh169/JohnCulpepper/100_4436.jpg
http://i256.photobucket.com/albums/hh169/JohnCulpepper/100_4437.jpg

[timebuilder]

Hello everyone,
I am brand new and this is my first post, I am trying to impress my boss by hunting down the answer to our problem. We got called to a job today with a "no heat" call on the 1st floor. We went to the roof and found that the RTU was not working, we popped the electrical door and the unit fired right up. We then powered it down to run some volt checks(we turned the power off). After doing our tests, we went to turn the unit back on but got no power at the on/off lever. We would've easily been able to diagnose the problem but we found NO electrical diagrams of where the power was starting and ending. I wrote down the serial and model numbers and was hoping maybe someone could help me out and email me the diagnostic charts(if you have them), I tried calling the TRANE rep in town, he said go online which I did and still no help. The unit is probably 20+ years older. So here are the serial and model numbers:

model # SFHB2006HJ20F22DC5T
serial # J87F81770

Thanks so much for your help!!!!!

Troy(the_apprentice)

Ok, Troy.

Now I know that the lever to which you were referring is the "disconnect." Sometimes the handle has a plastic cover of black or red, or just a bare metal loop.

I also surmise that perhaps you should read my electrical intro, stored here:

http://hvac-talk.com/vbb/showthread.php?t=431542

You will have to get your 15 posts and apply for pro membership to get access.

The pictures in the post right before this one show the inside of a disconnect. If you have never done so, have someone who HAS done so take a moment to demonstrate how to check the voltages in that box. This process is one that requires a degree of concentration and 100% awareness of where your hands and fingers are at ALL times.

If you had been running the unit, then powered it down, and then had no power when you restored the disconnect, you either have a problem with your disconnect or you have an open at the power distribution panel. In my experience, the breakers in the distribution panel act more quickly than the overcurrent protection on the roof, so the fuses could be fine up there, and the power is tripped at the power panel.

So, if there is no power on the "LINE" side of your disconnect, then you need to go downstairs and find the breaker or fused safety switch for the unit in question. If it tripped, your next task is to find out "why."

[DPSwitch]

I just can't quite get past the "powered it down to run some volt checks" part... lol

[timebuilder]

I just can't quite get past the "powered it down to run some volt checks" part... lol

Hey, we were all there at one point or another.

When I started working with crystal radios at age 8, I though anything that happened with a meter was a "volt check." :yes:

Four years later, I had built my first super-heterodyne receiver, and things started falling into place.

As others have mentioned, the most important thing for a tech is to remain safe and "un-shocked." That is MUCH more important than impressing your boss.

[yellowirenut]

do u have a journeyman? If u are working on thees units and don't know about a disconnect or how to determine where voltage is coming from , u should not be working alone yet.

[DPSwitch]

Timebuilder.....I reckon....lol

Nice work on the understanding electricity post btw.

[timebuilder]

Timebuilder.....I reckon....lol

Nice work on the understanding electricity post btw.


Thanks.

I have to give a lot of credit to my influences who made electricity (and electronics) fun for me. Companies like Heathkit and Eico, and men like Don Lancaster who wrote for Popular Electronics Magazine and Forrest Mims who wrote many great books for Radio Shack.

http://www.forrestmims.org/biography.html

One more thing, Troy. Yellowirenut has a point. You might benefit from some more guidance before being sent out on your own for electrical diag work. We want you here alive and well for years to come, so you can then share YOUR experiences with new techs.

[timebuilder]

Troy-

I just noticed you are in Saskatchewan. That means your RTU may be fed by 575 volts. Of course, these voltage values are just guides. Our 480 often goes to 500 volts, so your 575 could exceed your protection factor of a typical CAT IV 600 volt meter. In your area, I would make sure I am testing with a meter good to 1,000 volts. That would be a CAT-III, 1,000 volt meter. There is more than one voltage in a category.

http://ecmweb.com/mag/electric_meter_safety_measure/

So, you need to be especially aware of what you are doing. Our 480 kills techs every year here, so I can only imagine that a 575 shock is even more dangerous.

Be careful.