Description
The Bosch RL036-1HZC-LLEPDA is a 3-ton horizontal water-to-air heat pump from the RL Series, Bosch's residential line for geothermal and water loop systems. It hangs above a ceiling, in an attic, or in a crawlspace and connects to ductwork the same way a horizontal air handler does, but it makes its own heating and cooling from the water loop instead of an outdoor condenser. Return air enters on the left end, supply air leaves the opposite end, and the water connections sit on the front-left of the cabinet.
Why a horizontal water source heat pump
Horizontal units are built for buildings where floor space is worth more than ceiling space. At 21.5" wide, 47" long and 19" tall, this cabinet fits above a dropped ceiling or in a soffit and leaves closets and mechanical rooms free. Because the compressor, coils and blower are all inside the one cabinet, there is no outdoor unit and no refrigerant line set to run, and each unit can be serviced or replaced without touching the rest of the system.
Picking the return side matters. On this left-return model, the filter rack and return air opening are on the left end when you face the control panel, and supply air leaves from the right end. Match it to your existing return duct and service access so you are not fighting the layout in the ceiling.
Rated performance
Bosch rates the RL Series to AHRI/ISO 13256-1 at all three standard application points. The numbers below are for this size with a copper water coil at 1,200 CFM and 9 GPM.
| Rating point | Cooling (BTU/h) | EER | Heating (BTU/h) | COP |
|---|---|---|---|---|
| Water Loop (86°F cooling / 68°F heating) | 37,700 | 13.6 | 40,000 | 4.6 |
| Ground Water (59°F / 50°F) | 41,850 | 16.9 | 32,000 | 4.1 |
| Ground Loop (77°F / 32°F) | 37,700 | 14.8 | 27,000 | 3.5 |
Use the water loop rating for a building loop held roughly between 60°F and 90°F. The ground water and ground loop ratings apply to open-well and closed geothermal systems.
Water coil
This unit uses a copper coaxial water coil, the standard choice for closed systems: building water loops with a cooling tower or fluid cooler, and closed geothermal ground loops filled with treated water or antifreeze. For open-loop well water, choose a cupro-nickel version instead.
Construction
- R-454B refrigerant, the low-GWP replacement for R-410A
- Coaxial copper water-to-refrigerant heat exchanger
- DuoGuard coated air coil for added corrosion resistance
- G90 galvanized steel cabinet lined with 1/2" 1.5 lb dual-density fiberglass insulation to keep noise and cabinet sweating down
- PSC blower motor with multiple speed taps for airflow setup
- 3/4" FPT water connections on the front-left, 3/4" FPT condensate drain
- Filter rack for a 18 x 30 filter on the return end
Electrical
| Power supply | 208-230V single-phase, 60 Hz |
|---|---|
| Minimum circuit ampacity (MCA) | 25.2 A |
| Maximum overcurrent protection (MOP) | 40 A |
Specifications
| Model | RL036-1HZC-LLEPDA |
|---|---|
| Bosch part number | 7734012641 |
| Series | RL Series (residential) |
| Nominal capacity | 3 ton |
| Configuration | Horizontal, left return, end discharge |
| Refrigerant | R-454B |
| Airflow | 1,200 CFM |
| Rated water flow | 9 GPM |
| Water coil | Copper coaxial |
| Blower motor | PSC |
| Unit dimensions (W x L x H) | 21.5" x 47" x 19" |
| Filter size | 18 x 30" |
| Shipping weight | 270 lb |
Before you install
Size the loop pump and piping for the rated 9 GPM, and use flexible hoses at the water connections so pump and compressor vibration does not carry into the building piping. Hang the unit on vibration isolators, pitch it slightly toward the condensate drain, and leave clear access to the control panel and filter. R-454B is an A2L (mildly flammable) refrigerant, so installation and service should be done by a technician trained on A2L refrigerants and your local code.
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