This is a Module 3 - Refrigerants and Refrigeration lesson.
Your third call of the day is at the Humidor. Your dispatch information informs you that the Humidor is under contract for sale and the buyer would like the HVAC system checked out. You are to meet him there and make no mention that the Humidor is for sale.
When you arrive, you meet the buyer. He has no idea about the HVAC system, including where it is, repair history, or if it has ever been serviced. Remembering that a great HVAC tech needs to be a great investigator, you ask the buyer if it is okay to investigate the situation to get a feel for the layout of the system. He gives you permission and this is what you find.
The Humidor is an upscale cigar shop/cigar bar in a complex with many other businesses and restaurants. As you begin to investigate you find that there is a Smoke Eater system in the ceiling.
Several feet away you notice what looks like a return air grille in the ceiling, and at the end of the hallway another apparent return air grille. The thermostat is in the hallway.
You look out back and see that there are dozens of condensing units outside, none of them labeled and most of them are running. You think, "This is going to be interesting". Saving this puzzle for later, you go back inside.
You spot an access panel in the ceiling near one apparent return air and a bigger access panel on the wall in the hallway near the other apparent return air.
You decide to start here. Removing the wall access panel, you spot the air handler mounted horizontally above the restrooms and verify where the return air grille is.
Moving on to the other access panel in the ceiling you remove it and find a small exhaust fan with a flex duct leading towards the back. Hmmm... looks like an exhaust fan to remove the smoke from the building.
Now that you have thoroughly investigated, you inform the potential buyer about the Smoke Eater and exhaust fan. He wants you to check them out too.
Turning on the Smoke Eater you can hear the fan running. Putting your hand up to the return and supply air there is barely any air flow. You open the system and find the carbon filters completely plugged with smoke residue. Removing the filters the air flow increases to normal levels. You write in your notebook, "Smoke Eater filters have not been changed in years (apparently), filters completely plugged and should be replaced."
You find the switch to the exhaust fan and find a faded note taped to it that says, "Exhaust fan broken DO NOT USE." At this point you decide to check out the HVAC system.
But... which one is the condensing unit??? This isn't going to be fun.
As you're scratching your head, you spot the entry point of the linesets (refrigeration piping) low in the wall. It comes out of the ground, immediately turns a 90 and enters the wall of the building. You touch the lineset and find that the suction line is cold and the discharge line is hot.
One-by-one, you remove the power from each condensing unit and run back to check the suction and discharge lines. You know that when you hit the right unit you will know by the temperature of the refrigeration lines, they will no longer be cool and hot. After several attempts you find the correct unit. Grabbing your Sharpie, you label the condensing unit for future reference.
Now it is time to check the HVAC system. You remove the cover and hook up you manifold gauges.
You know the system has been running for at least 15 minutes so you record your pressures and temperatures.
You also spot this (condensing coil):
Based on what you have found what is your diagnosis?
Why?
What will you tell the buyer?
Your third call of the day is at the Humidor. Your dispatch information informs you that the Humidor is under contract for sale and the buyer would like the HVAC system checked out. You are to meet him there and make no mention that the Humidor is for sale.
When you arrive, you meet the buyer. He has no idea about the HVAC system, including where it is, repair history, or if it has ever been serviced. Remembering that a great HVAC tech needs to be a great investigator, you ask the buyer if it is okay to investigate the situation to get a feel for the layout of the system. He gives you permission and this is what you find.
The Humidor is an upscale cigar shop/cigar bar in a complex with many other businesses and restaurants. As you begin to investigate you find that there is a Smoke Eater system in the ceiling.
Several feet away you notice what looks like a return air grille in the ceiling, and at the end of the hallway another apparent return air grille. The thermostat is in the hallway.
You look out back and see that there are dozens of condensing units outside, none of them labeled and most of them are running. You think, "This is going to be interesting". Saving this puzzle for later, you go back inside.
You spot an access panel in the ceiling near one apparent return air and a bigger access panel on the wall in the hallway near the other apparent return air.
You decide to start here. Removing the wall access panel, you spot the air handler mounted horizontally above the restrooms and verify where the return air grille is.
Moving on to the other access panel in the ceiling you remove it and find a small exhaust fan with a flex duct leading towards the back. Hmmm... looks like an exhaust fan to remove the smoke from the building.
Now that you have thoroughly investigated, you inform the potential buyer about the Smoke Eater and exhaust fan. He wants you to check them out too.
Turning on the Smoke Eater you can hear the fan running. Putting your hand up to the return and supply air there is barely any air flow. You open the system and find the carbon filters completely plugged with smoke residue. Removing the filters the air flow increases to normal levels. You write in your notebook, "Smoke Eater filters have not been changed in years (apparently), filters completely plugged and should be replaced."
You find the switch to the exhaust fan and find a faded note taped to it that says, "Exhaust fan broken DO NOT USE." At this point you decide to check out the HVAC system.
But... which one is the condensing unit??? This isn't going to be fun.
As you're scratching your head, you spot the entry point of the linesets (refrigeration piping) low in the wall. It comes out of the ground, immediately turns a 90 and enters the wall of the building. You touch the lineset and find that the suction line is cold and the discharge line is hot.
One-by-one, you remove the power from each condensing unit and run back to check the suction and discharge lines. You know that when you hit the right unit you will know by the temperature of the refrigeration lines, they will no longer be cool and hot. After several attempts you find the correct unit. Grabbing your Sharpie, you label the condensing unit for future reference.
Now it is time to check the HVAC system. You remove the cover and hook up you manifold gauges.
You know the system has been running for at least 15 minutes so you record your pressures and temperatures.
You also spot this (condensing coil):
Based on what you have found what is your diagnosis?
Why?
What will you tell the buyer?