Graphite Dave
Dave Orton
My 08 was purchased with the optional Espar water heater. The plan was to use the heater for space heating and to heat water for the shower. Thanks to Mercedes engineering there are several reasons why this was difficult to accomplish. I will still use the Espar for space heating but would not buy the Espar option again. Space heating would be done better with an aftermarket Espar air heater. My electrical system is different than most conversions. Since I wanted 3 stage battery charging and did not want to direct connect my house battery to the Sprinter battery, I have two inverters. The 1000 watt "house" inverter makes 120 volt pure sine power from the house 255 amp-hr. battery. The 600 watt "vehicle" inverter makes 120 volt pure sine power from the Sprinter 12 volt system. The Sprinter engine must be running before the vehicle inverter will operate. The vehicle inverter will be used for the power to heat the water.
The portable hot water tank will consist of 3 parts:
1. Tank - 5.16 gallon stainless beer keg that is 9 1/4" dia. x 23 1/4" tall and weighs 12 lbs. The beer outlet is a 1 3/4" dia. hole at the top of the keg. The SS pipe and check valve have been removed from the keg. Caution: even an empty keg has high pressure in the tank. This pressure must be relieved before the pipe and valve are removed. Be sure to manually press down the rubber ball check valve to be sure pressure is gone. After the pressure is released, the pipe and valve can be extracted by removing the spring retaining ring with two small screwdrivers. I acquired the tank for free.
2. Heating element - This is a "Hottrod" electric conversion 6 gallon water heater part # HR6. I purchased this from AdventureRV.net for $94.00 delivered. Kit was designed to replace the drain plug on Suburban and Atwood RV propane heaters so shore power can be used to heat water instead of propane. Kit includes the 450 watt Calrod heating element, a 90 deg. to 150 deg. adjustable thermostat and an electric cord. It will screw into a SS coupling added to the bottom of the keg. The thermostat will be attached to the keg side above the heating element.
3. Pump - This is a Rule "Charge N' Flow" pump part # RP280KR. I paid $71.24 from Amazon.com delivered. The kit includes a 1 1/2" dia. 12 volt 4.7 gpm pump, 8' of hose, spray nozzle, battery, battery charger and a 12 volt plug. Pump will be installed in tank by dropping it through the beer outlet.
Two SS couplings will be welded to the tank. The one on the side at the bottom of the tank will be for the heating element and the other will be a 3/4" coupling welded on the opposite side at the top. The top coupling will have a street ell installed with a reducer for a 3/8" NPT Norgren air cylinder valve exhaust muffler part # C/S3 to let air into tank as the water is pumped out. The muffler will be removed to fill the tank with water. I will have to figure out how to suspend the pump in the tank so it does not touch the heating element at the bottom. The completed tank will weigh about 60 lbs when full of water. The water can be heated several ways: put tank in the sun, 120 volt shore power or 120 volt power from the vehicle inverter when the engine is running. The pump can be run from the house battery or from its portable battery. The portable battery is supposed to be good to pump 100 gallons. So tank can be used inside or outside of van. The thermostat will be set for about 100 deg. and only the water in the tank will be used to shower. Cold water will not be mixed with the tank hot water. About 4 gallons of water will be available.
Thanks to "srsosbso" for starting the "12v. hot water heater" thread. The discussion led me to this solution. If this works as expected, it is simpler than tapping into the Sprinter's cooling water system. I will document the tank build as I put it together.
The portable hot water tank will consist of 3 parts:
1. Tank - 5.16 gallon stainless beer keg that is 9 1/4" dia. x 23 1/4" tall and weighs 12 lbs. The beer outlet is a 1 3/4" dia. hole at the top of the keg. The SS pipe and check valve have been removed from the keg. Caution: even an empty keg has high pressure in the tank. This pressure must be relieved before the pipe and valve are removed. Be sure to manually press down the rubber ball check valve to be sure pressure is gone. After the pressure is released, the pipe and valve can be extracted by removing the spring retaining ring with two small screwdrivers. I acquired the tank for free.
2. Heating element - This is a "Hottrod" electric conversion 6 gallon water heater part # HR6. I purchased this from AdventureRV.net for $94.00 delivered. Kit was designed to replace the drain plug on Suburban and Atwood RV propane heaters so shore power can be used to heat water instead of propane. Kit includes the 450 watt Calrod heating element, a 90 deg. to 150 deg. adjustable thermostat and an electric cord. It will screw into a SS coupling added to the bottom of the keg. The thermostat will be attached to the keg side above the heating element.
3. Pump - This is a Rule "Charge N' Flow" pump part # RP280KR. I paid $71.24 from Amazon.com delivered. The kit includes a 1 1/2" dia. 12 volt 4.7 gpm pump, 8' of hose, spray nozzle, battery, battery charger and a 12 volt plug. Pump will be installed in tank by dropping it through the beer outlet.
Two SS couplings will be welded to the tank. The one on the side at the bottom of the tank will be for the heating element and the other will be a 3/4" coupling welded on the opposite side at the top. The top coupling will have a street ell installed with a reducer for a 3/8" NPT Norgren air cylinder valve exhaust muffler part # C/S3 to let air into tank as the water is pumped out. The muffler will be removed to fill the tank with water. I will have to figure out how to suspend the pump in the tank so it does not touch the heating element at the bottom. The completed tank will weigh about 60 lbs when full of water. The water can be heated several ways: put tank in the sun, 120 volt shore power or 120 volt power from the vehicle inverter when the engine is running. The pump can be run from the house battery or from its portable battery. The portable battery is supposed to be good to pump 100 gallons. So tank can be used inside or outside of van. The thermostat will be set for about 100 deg. and only the water in the tank will be used to shower. Cold water will not be mixed with the tank hot water. About 4 gallons of water will be available.
Thanks to "srsosbso" for starting the "12v. hot water heater" thread. The discussion led me to this solution. If this works as expected, it is simpler than tapping into the Sprinter's cooling water system. I will document the tank build as I put it together.
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