Rhode Island Replacing 7 year old heat pump.

Discussion in 'General Discussions' started by ChrisJ, Jun 24, 2016.

  1. ChrisJ

    ChrisJ Active Member Forum Leader

    The new packaged unit is quite different in size. Wondering if it's ok to raise it up on a platform of wood with the plastic base then some rigid foam insulation? The difference in height between the 2 is around 10". This will minimize the duct work changes. Would also allow me to run hoses low and in front of the unit because my pump is to the left of the unit, connections are on lower right side.

    Foot print: 30 1/2"w X 28"d, they supplied a 30 X 30 plastic base. Should I forget the plastic base? It's a hair small in one dimension.

    ChrisJ
     
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    We have generally used angle iron (or unistrut) in such cases, but whatever you wish to use, go for it. You do need to be conscious of limiting vibration noise and moisture that can rot wood.
     
  3. ChrisJ

    ChrisJ Active Member Forum Leader

    So you would weld a metal platform of some sort.

    The old one is sitting on a 1" thick piece of polyiso insulation. That is on my cement slab that has radiant, so underneath the cement is 2" insulation and vapor barrier. Only moisture would be spills.
     
  4. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    We just cut and drill bolt holes if doing angle iron - skips lugging a welder out. But if you have one, go for it. Or unistrut simplifies the process.

    edit - I should add that a 12" ducting collar (or whatever) might be the simplest solution.
     
  5. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    We poured a concrete pad for 10 inches, or did a steel frame, or build wood scaffolds.. I just found it important to ensure that compressor vibration cannot resonate through the house. Thus I don't like to hang them from the ceiling, and I like an insulator between the floor and the heat pump. Make sure the platform is flat, since the HPs are designed to stand on a flat surface. Don't put them on blocks.
     
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I not sure why we are not allowed blocks.

    How about a coffee table made or treated lumber and an OSB tabletop. Then add the vibration isolators.
     
    Last edited: Jun 24, 2016
  7. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    "Top and rear air discharge vertical units should be mounted level on a vibration absorbing pad slightly larger than the base to provide isolation between the unit and the floor."

    "Mount unit on a sound absorbing pad, extruded polystyrene, rubber or cork pad."
    Waterfurnace installation manual

    "Unit Air Pad. All vertical geothermal heating and cooling equipment should be placed on either a formed plastic air pad, or a high density, closed cell polyethylene pad. This helps eliminate vibration noise that could be transmitted through the floor.
    The use of conrner pads alone is not recommended."
    Enertech Installation Manual

    The weight of the compressor bends the unit floor down a few millimeters and could put stress on the internal piping to the compressor. Plus the floor will become a resonator. The unit will run more noisy.
     
  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    OK. I want to see the unit bend 3/4 OSB.
     
  9. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Bottom line is:
    They recommend it, and I had units which run louder when placed on corner blocks.
     
  10. ChrisJ

    ChrisJ Active Member Forum Leader

    I need a new return "box" that mounts to the filter area. I was hoping to reuse the connector duct that comes down from the ceiling mounted horizontal main trunk. It has a slight "S" shape, 20" X 10". See picture. It's only a little bit narrower then the existing return box.

    The new return box will be 27 1/4"w x 26 1/4" high x 14" deep. Should the connector be replaced with one that is closer in width to the new return box?
     

    Attached Files:

    Last edited: Jun 28, 2016
  11. ChrisJ

    ChrisJ Active Member Forum Leader

    The new unit is in!! My Hydro-Temp nightmare is over.

    I ended up making a wood platform w/2" rigid foam to make up the 10" difference in height. Measured for and had 2 new return pieces made.

    I was able to reuse the supply plenum.

    CJ
     
    heatoldhome likes this.
  12. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    :)
    Congrats!
     

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