Tankless Size Chart

Flow rate and temperature rise of small tankless water heaters for ADUs, cabins and off-grid buildings

Section 11

Propane supply pressure, placement and venting by tankless model

This table lists the placement, propane supply pressure and venting that Rinnai and Eccotemp publish for 7 propane tankless models. Venting and gas supply carry carbon monoxide and fire risk. This page gives no installation advice. Each row has a note that links its source.

Table 11.1 Published gas and placement requirements
ModelPlacementPropane supply pressureVentingSource
Rinnai V53DePExternal (outdoor) residential8.0 to 13.5 in. w.c.Outdoor unit[1]
Rinnai V65ePExternal (outdoor) residential8 to 13.5 in. w.c.Outdoor unit. Clearances to combustibles: top 12 in., bottom 12 in., sides 6 in., front 24 in.[2]
Rinnai V75ePExternal (outdoor) residential8 to 13.5 in. w.c.Outdoor unit. Same clearance table as the V65e[3]
Eccotemp SH12-A-LPIndoorNot listed on the product page3-inch horizontal and vertical vent kits, sold separately[4]
Eccotemp SHLX-LPIndoorNot listed on the product page3-inch horizontal and vertical vent kits, sold separately[5]
Eccotemp SH22-ILPIndoorNot listed on the product page4-inch horizontal and vertical vent kits, sold separately[6]
Eccotemp SH22-LPOutdoorNot listed on the product pageEccotemp says no venting is required for the outdoor unit[7]

11.2 Installation manual and code

Each spec sheet and product page above points to an installation manual. The manual and the local fuel gas code set vent length, termination distances, combustion air and gas pipe size. Rinnai's sheets say that local, state, provincial, federal and national fuel gas codes must be adhered to prior to and upon installation[2].

A licensed gas installer or plumber sizes the propane line and regulator and installs the vent. Indoor gas appliances also fall under local rules for carbon monoxide alarms, which the building department sets.

Notes and sources

  1. Rinnai, non-condensing tankless brochure with United States Ground Water Temperature Map and V53De table, 06/2022 (PDF hosted by Woodstove Pro)
  2. Rinnai, V65e specification sheet with water flow curve (PDF)
  3. Rinnai, V75e specification sheet with water flow curve (PDF)
  4. Eccotemp, SmartHome SH12-A-LP product page
  5. Eccotemp, SmartHome SHLX-LP product page
  6. Eccotemp, SmartHome SH22-ILP indoor product page
  7. Eccotemp, SmartHome SH22-LP outdoor product page