Model F High Capacity Instantaneous Steam Fired Water Heater
The Hubbell F Model is a compact, highly efficient, packaged instantaneous steam fired water heater perfect for new or replacement water heating requirements. This highly efficient Hubbell heater requires no large storage tank, is easily installed and requires minimal floor space. Furthermore, the Hubbell F model utilizes a helical coil as its source for heat transfer and is up to 40% more efficient than traditional "U" tube heaters. When you specify and install a Hubbell steam fired water heater, you will have confidence in knowing the owner will be provided with a long lasting, trouble-free source for hot water.Compact High Capacity Design
- On demand water heater eliminates the need for a large storage tank
- Advanced design requires only 7 Sq.Ft. of floor space
- All steam controls are located within the steel frame
Heavy Duty Construction
- Water heater is factory assembled on an all welded steel mounting frame to save time and money during installation
- All steam operating controls are factory selected, sized and piped
- Ready for water and steam service connections
- Heat exchanger is ASME Section VIII stamped and registered with the National Board
- Factory fitted protective shroud covers the heat exchanger for improved safety
Spiral Design Heat Exchanger
- Helical coil design is up to 40% more efficient than traditional "U" tube coils
- No standby heat loss
- Feed forward blending valve controls hot water +/- 4°F
The heart of the Hubbell Instantaneous Steam fired water heater is a compact, highly efficient and versatile spiral tube heating coil which offers many advantages over a conventional "U" tube design including:
- 100% counterflow for heat-transfer rates up to 40% greater than equivalent stright tube exchangers.
- Pressure drop is minimized.
- Bourdon tube configuration that allows entire assembly to expand and contract without localized stresses. Failure from thermal shock or mechanical process is rare.
- No baffles.
- ASME Section VIII UM standard.
- Variety of materials available to suit specific applications.
- Compact design for easy maintenance.
- Parts in stock to prevent long and expensive down times.
The temperature regulating device in a Hubbell Instantenous Steam water heater is a "feed forward" blending valve design to assure safe and accurate temperature control of the heated water for an entire range of flow capacities. A purely mechanical operation, the Hubbell blending valve will provide +/- 4°F temperature control without the use of thermostatic sensing devices.
How the blending valve works
- The proportioning valve plug is constructed from Hastelloy C and is regulated by movement of the neoprene diaphragm, induced by pressure differentials in the sensing head.
- A sensing line "loads" the top portion of the diaphragm with supply line cold water pressure while blended water outlet pressure is being sensed below.
- Flow demand imparts a pressure imbalance above (+) and below (-) the diaphragm resulting in movement of the diaphragm and proportioning plug.
- The movement aligns ports in the plug with supply ports in the valve body, introducing the correct proportion of hot and cold water.
- This action automatically generates blended hot water through all rated flow capacities at the chosen preset temperature (+/- 4°F).
The integral fail-safe system permits steam travel in the event of plug restriction or parts failure, opening an auxiliary cold water port. Cold water flooding yields cooler water, or when parts fail, no water at all.
Temperature is easily adjusted by side-to-side movement of the control rod on the valve body. Stabilization adjustments are made during initial start-up by rotation of the control rod. All settings are locked in with a locking ring and set screw.
- Cold Water enters via the inlet piping and branches off to supply both the cold port on the blending valve and the heat exchanger.
- The cold water passes throught the coils in the heat exchanger and is heated by the surrounding steam in the shell.
- Hot water exits the heat exchanger and enters the hot port on the blending valve.
- The plug assembly in the blending valve opens the hot and cold ports to provide the precise amount of hot and cold water in order to achieve the desired output temperature water +/- 4°F.
- The heated water exits the unit at the base of the blending valve.
Domestic water heating applications with steam supply pressure greater than 15 psi require a steam pressure reducing valve as well as a separate steam pressure relief valve to be installed in the incoming steam supply line prior to the heat exchanger shell.
Hubbell can supply the pressure reducing valve as an option. Steam pressure relief valve supplied by others.
F Model Optional EquipmentHeating Coil
- The factory-supplied, all welded, heavy duty steel stand is high enough to accomodate the condensate piping and traps, therefore no special field-erected stand is required.
- Hubbell is committed to increasing operating efficiencies and improving safety features. Therefore, each water heater is supplied with a factory jacket and insulated heat exchanger. Without this feature, the heat exchanger (with a surface temperature in excess of 200°F) acts as a radiator and adds to heat loss inefficiencies and is a severe safety hazard for personnel who may inadvertently come in contact wit the surface of the exchanger.
- The Hubbell water heater will fit through most doorways, for simple and time saving installation.
- With only 7 square feet of floor space required for installation, compared to conventional storage water heaters the Hubbell water heater will require significantly less mechanical room space.
- Traps and strainers are factory piped, assembled and tested to save time and money during installation and start-up.
- Built-in relief valve (water side) set at 165 psi to signal over-pressure condition.
- Double wall tubing with leak detection port (F30 and F60 sizes only)
- Tubing materials available: Standard is copper, Optional materials are Admiralty, 90/10 Copper-Nickel, Stainless Steel (Type 304 or 316)
Note:Tubing materials other than copper will exhibit lower maximum capacities
- Shell Construction: Standard is Cast Iron, Optional materials are Cast Steel, Cast Bronze, 90/10 Copper-Nickel, Stainless Steel (Type 304 or 316)
Note:Cast steel shell ratings: F30: 225 psi @ 350°F F60 & F90: 225 psi @ 350°F F120: 225 psi @ 350°F
- In order to limit the steam pressure in the heat exchanger shell a steam pressure reducing valve is factory supplied and shipped loose for in-the-field installlation
- Single solenoid safety system opens the sensing line to the blending valve in order to limit the hot water output in the event of an over temperature condition. Requires 5 Amp, 120 Volt service.
- Double solenoid safety system opens the sensing line to the blending valve as well as closing the steam supply to heat exchanger in the event of an over temperature condition. Requires 5 Amp, 120 Volt service.
- All steam components (traps, strainers) shall be Cast Steel construction
- If water hardness exceeds 120 ppm, scale build-up can reduce efficiency. A factory packaged Klean-Koil Kit™ with built-in connections will allow for quick and easy in-place cleaning of the coil to remove these deposits thereby avoiding long periods of down time and expensive maintenance costs.
- Optional temperature control to +/- 3°F of set temperature.
- All 316 Stainless Steel blending valve and 316SS water piping
- Fixed temperature 3 way diverting valve, one (1) 1" globe valve, and two (2) 1" check valves are shipped loose for in-the-field installation.
- Same as previous option except with 3-way diverting valve that has an adjustable range.
- 3 way diverting valve is factory fitted and piped to the water heater.
Please note: optional equipment may impact overall dimensions and weight. Please request submittal drawing from factory.