Heat Pump? - InspectionNews

David Banks · #1 (**permalink**) 04-30-2007, 12:27 PM

Large multi story Condo complex. Maintenance man brings me to roof. No individual unit condensing units, just one large one that appears to be for all units. Interior unit says Heat pump. So does exterior unit. Trouble is I see no refrigerant lines on interior or exterior. Maintenance man knows nothing just says heat and AC are Electric.
Thermostat has no emergency heat mode. Do you think the monster on the roof is not used any more and the interior unit is a packaged unit-compressor evaporator all in one?
What am I looking at?

Jerry Peck · #2 (**permalink**) 04-30-2007, 12:45 PM

That a/c on the roof is likely a PAC unit and is for the common areas.

The individual a/c units are likely connected to a chiller someplace. There would be no refrigerant line inside, just water lines to and from the heat pump in that closet.

Your photo angle does not show if there are, or are not, water lines there.

David Banks · #3 (**permalink**) 04-30-2007, 02:06 PM

Jerry. No water lines. I was looking for that. Did not see any cooling tower or water chiller. I did not get behind the building due to restrictions. Could the water lines come in through the back of the interior system behind the gypsum board. Newer interior unit. Friedrich. Model VHA18K50RTG-3
Serial LDEV00071
No safety pan.
What is PAC unit? Thanks for any ideas. I am stuck on this one.

Jerry Peck · #4 (**permalink**) 04-30-2007, 03:06 PM

"Could the water lines come in through the back of the interior system behind the gypsum board."

Yes, and I considered that, but, they should not. the water hoses and valves should not be *in* the cabinet, but they 'could be', and very well might be.

PAC units is what Package A/C units are referred to.

They could also be referred to as RTU for Roof Top Unit.

Many times in plans you will see ducts labeled as RTU1, meaning that they go all the way up to the Roof Top Unit 1, and then the 'RTU' is labeled PAC1. No consistency in labeling.

David Banks · #5 (**permalink**) 04-30-2007, 03:17 PM

I suppose my interior unit could be a packaged unit? I did see one in a Condo unit a while back.

Jerry Peck · #6 (**permalink**) 04-30-2007, 03:24 PM

Quote:

Originally Posted by David Banks

I suppose my interior unit could be a packaged unit? I did see one in a Condo unit a while back.

In a sense, it is, if it is using water from a chiller and the compressor is located in the unit (like most of those are).

David Banks · #7 (**permalink**) 04-30-2007, 04:03 PM

Jerry. Found it! Packaged unit that is heat pump with electric heat. Serial number indicated this one is also a heat pump. VHA.

Jerry Peck · #8 (**permalink**) 04-30-2007, 04:15 PM

I need help here.

That is a completely self-contained package unit. No chiller lines either.

Okay, that I understand.

What I do not understand is that, well ... here is an example:

You take a refrigerator, open the door, now, how long will it take that refrigerator to cool the room it is in?

See my problem?

How does that work? I don't see a way to discharge the hot air created by its cooling, or discharge the cool air created by the heat pump.

Michael Thomas · #9 (**permalink**) 04-30-2007, 04:43 PM

It's a wall-plenum unit, has to back up to an exterior wall.

Dom D'Agostino · #10 (**permalink**) 04-30-2007, 04:48 PM

Jerry,

Sounds like a typical through-wall A/C system:

The instructions state the unit must be mounted on an exterior wall.

Quote:

VERT-I-PAK ® units must be installed on an outside wall.

It also describes, in great detail, the condensate removal system:

Quote:

13) Condensate Disposal System

The internal drain connections are 3/4" FPT fi ttings on the right, left
and outdoor side of the unit. See Figure 10 on page 12. The chassis
is designed with a condensate drain system that has 3 parts. The
three parts work as follows:

Part 1: The system’s first stage increases energy efficiency
utilizing a factory installed fan that slings the cold
condensate onto the hot outdoor coil.

Part 2: When high outdoor humidity prevents the slinger from

disposing of all the condensate, the excess condensate overflows
into the internal drain connection.

Part 3: If Parts 1 & 2 fail for any reason, excess condensate

overflows from a spillway directly into the wall plenum

to the outside of the building. IF THIS OCCURS, THIS
IS YOUR WARNING THAT THE CHASIS OR DRAIN
NEEDS SERVICING.

David Banks · #11 (**permalink**) 04-30-2007, 05:18 PM

Dom. That is interesting because I am recommending a safety drain pan. Maybe with the stains on the exterior wall it is not needed? But who the hell will see it at the back of the building on the 5th floor?

Jim Luttrall · #12 (**permalink**) 04-30-2007, 05:51 PM

That drain system sounds like it meets the intent of the IRC condensate disposal method. (I know the IRC is the RESIDENTIAL code) And since it is an engineered system, I would hesitate to recommend another pan. Seems like it is a pretty well thought out system.
Typical through the wall system except it blows through ductwork.
Jim

Jerry Peck · #13 (**permalink**) 04-30-2007, 06:50 PM

Oops ...

I read through that thing probably 4-5 times and missed that every time????

David Banks · #14 (**permalink**) 04-30-2007, 08:39 PM

Jerry's Human!
Thanks all.

#15 (**permalink**) 04-30-2007, 10:26 PM

My first thought was similar to Jerry, Chilled water system with a chilled water coil in the condo.

Second was when I read it was a Friedrick unit I thought the same as Dom stated, a through wall system.

#16 (**permalink**) 05-06-2007, 02:04 PM

actually a pac unit just means that the heat and a/c is created in one unit. they could be package gas, or package heat pump, ANY THING ELSE HAS ITS OWN NAME.