Heat Pump to Building Clearance

[Bib Overalls]

I'm putting a package unit 3.5 ton heat pump behind (and for) my shop. I have the specs for the unit but I can not find any reference to how much clearance is required. Is there a good rule of thumb to follow when placing one of these units near a building? I want to minimize duct length but I don't want to be so close unit efficiency is compromised.

 

[lzenglish]

I'm putting a package unit 3.5 ton heat pump behind (and for) my shop. I have the specs for the unit but I can not find any reference to how much clearance is required. Is there a good rule of thumb to follow when placing one of these units near a building? I want to minimize duct length but I don't want to be so close unit efficiency is compromised.

It is hard to say, without any pictures, or any more info. I would ask you, is this unit going to be ducted to a supply and return air duct system within the shop? Or, are you going to just **** it up to the shop building, and dump the supply and return air in with turning vanes, and louvers? The tighter the bend in the ducting, the more friction loss, and back pressure on the system. And the closer the supply and return air registers, the more likley you will have short cycling.

Wayne

 

[Bib Overalls]

The package heat pump will sit on a pad behind the shop. The return duct will terminate in a box at the wall with a filter and some sort of protective cover. Most likely expanded steel mesh. The supply duct will 90 just inside the wall and run upward through a storage loft and terminate with registers facing out. I have the option of running horizontal duct work later if I am not satisfied with the "throw."

My unit is about 3' x 6' in size and my pad is 6' x 7' so I have the option of spacing the unit out about 3.5' and still have a direct shot at the building.

 

[lzenglish]

Sounds like you have pleanty of room. Do you have the transition made up for it yet? I would just keep the bends as gradual as possible once you are inside. Below is a picture of a mobile 5 ton York Pathfinder unit, that I put together for the Military about 30 years ago. So, the tin knockers can do anything you want with your transition.

Wayne

 

[pop pop]

Keep it well beyond the drip line/snow falling/ice falling line.

 

[pseudorealityx]

Look up the model you have online, and the catalog should clearly call out the required distances. It will vary per side. The side you access to do maintenance is typically 48" clear to allow you to open the access doors, get the compressor out, etc. The clearances on the condenser coils side can range anywhere from 18" to 60" clear, just depending on the design.

Just to be safe, I'd give yourself 48" in any direction, and completely open on top.

 

[NUTTSGT]

SPAM post #3
reported

 

[Zick]

SPAM post #3
reported

I don't think the OP appreciates you calling him spam.

 

[Bib Overalls]

The heat pump was delivered today. We set it up 3' from the wall, the maximum with the 6' x 6' concrete pad that I have. The dealer said I could save a few bucks on duct work by moving it a little closer but I passed. The I-beam box lifts the unit so that the duct work has a straight shot into the building. We have room to move the unit in or out, left or right to fine tune duct fitment once the sections are on site. I'm pleased.


Heat Pump 1 by Bib Overalls, on Flickr


Heat Pump 2 by Bib Overalls, on Flickr

 

[ezriderga]

Looks great!

 

[Bib Overalls]

Today I finished up the hard work and turned on my heat pump for the first time. What a pleasure it was to hear the compressor kick in and feel the cold air flowing out of the supply registers. The last task I had to do was build a box for the return air grid and filter. The supply house sent out the wrong grid. It was to small for the specified filter even though both were labeled 24" x 24". I had already built the box and mounted it to the wall with adhesive caulk and screws when I discovered the mistake. Fortunately, the box had a little extra "meat" and I was able to enlarge the opening in place with my circular saw. No one will ever know.


Heat Pump 3 by Bib Overalls, on Flickr

I secured the supply duct work in place with Good Stuff foam. The low expanding version. It does a great job. I have some clean up and detail work to do. Fortunately, it is not critical and I can do it in air conditioned comfort.


Heat Pump 4 by Bib Overalls, on Flickr


Heat Pump 5 by Bib Overalls, on Flickr

 

[lzenglish]

Looks like a real clean job to me! Congrats! I hope you put a turning vane or two in the supply duct?.

Wayne

 

[Bib Overalls]

I hope you put a turning vane or two in the supply duct?.

Wayne

Yes, the duct fabricator cut a panel to ease the flow through the transition from horizontal to vertical. You can see the screws that hold one end in the first picture above.

Did not put one at the top of the duct work. I can add one if you think it is necessary. The last length of duct has not been locked in place yet.

 

[lzenglish]

Yes, the duct fabricator cut a panel to ease the flow through the transition from horizontal to vertical. You can see the screws that hold one end in the first picture above.

Did not put one at the top of the duct work. I can add one if you think it is necessary. The last length of duct has not been locked in place yet.

Absolultly add one! Imagine the dead head the supply air would encounter with the square ducting, if it did not have a smooth transition to help it turn that 90 degree angle, to travel down its path. Once you get the main trunk installed, there is no need for anything more then balancing louvers, or registers.

Wayne

 

[pseudorealityx]

Absolultly add one! Imagine the dead head the supply air would encounter with the square ducting, if it did not have a smooth transition to help it turn that 90 degree angle, to travel down its path. Once you get the main trunk installed, there is no need for anything more then balancing louvers, or registers.

Wayne

Agree. It's cheap and there's no reason not do to do it. Better flow, quieter operation, motor will pull less amps, etc.

 

[coolreed]

Boy that is a 'Honkin' big unit. Nice work.