Translate

Monday, January 25, 2021

an exemplary heat pump water heater installation

Here is my new heat pump water heater installation, for assessment by the reader. I have responded to new demands, exceeding those of the cheap electric heater now recycled. It is taller. Water pipes to the tank are longer, yet are simpler and more secure. Thoughtful cradles at last support against tip-over in an earthquake roll. Behind the drywall, at both sides of this room corner, house shape is stabilized by 1x8 shiplap sloped 45°; now benefitting the tank seismic support. I know where the wall joists are, from nail locations on interior drywall. At the cradle assemblies, the larger pieces of 3/4" plywood are set with long screws finding wall joists if I am lucky. Rely actually upon 1 5/8" deck screws engaging shiplap, strong for lateral loads, to carry seismic loads from the cradle assemblies.  The cradle assemblies adjusted to best tank position, are bonded to the bigger plywood pieces and to the shiplap directly, with 2" deck screws.

A new, simple, dedicated plumbing drain, serves the pumped drip of a condensing gas furnace, as well as the flood of HPWH condensate. Users, the wonderful renters of my home, have informed choices to readily make upon hot water temperature and economy of mode. They will be pleased by more than 50% savings of energy for hot water, amounting to more than $20 per month. I am pleased to have achieved this prideful conservation at material cost of just $577, where the well-rebated $1200 heater cost just $399.



Learn more in this job photo album. See that I have followed manufacturer instruction that tank water lines not atop the tank, so distant from wall connections, should be flexible PEX. PEX couplings at the tank are wrench-detachable without need of oddly-prescribed little metal garden hoses having dangerous quickly-releasable face seals.  The tank is tied to cradles well-anchored upon diagonal shiplap behind the drywall. Condensate is directed to a dedicated plumbing drain. 














Here are the Rheem graphics of expected installation. My installation is superior in having the Cold shutoff very accessible with an inherent heat trap within the wall; isn't that true? I don't understand the thermodynamics of this.






















Google the title of this post, to see if residential HPWH installation standards exist.

Find these videos:

A 2014 installation by This Old House has odd, simpler HPWH installation of an unidentified unit where tank piping is at the top.

How to Install a Heat Pump Water Heater | This Old House


Federal resources of Bonneville Power Administration are offered through Hot Water Solutions, an initiative of NEEA, Northwest Energy Efficiency Alliance.

How To Install a Heat Pump Water Heater: Professional Version

How To Install a Heat Pump Water Heater: Consumer Version


In this Rheem video see a Rheem unit like mine, with side-mounted water connections and no details of installation.

How it Works: Rheem Prestige Series Hybrid Heat Pump ...


See that side-mounted water connections are a common innovation with heat pump water heaters, Manufacturers should align against destructive plumbing code that demands tank connection with at least 18", not more than 24" flexible metal hoses. Could anyone defend need of that? Every added connection adds cost and failure risk.  Please find marked-up Plumbing Code for State of Oregon. I find fault too, with seismic requirements. Big steel straps have no value without intelligent anchors. If slack permits a heavy tank to roll with momentum, straps are doomed.


At 2/27/2021 add reference to installation of a SANDEN CO2 found in this Matt Risinger YouTube video. Choose an outdoor unit if you can, for the better efficiency and quiet.

Start viewing at 12:00.





Find an overview of heat pump water heaters, by Matt Risinger, Top 5 Heat Pump Water Heaters, July 2020.