Hot water
- Thread starter Pokiejoe
- Start date
JohnDar
Prolifically Gabby Member
Short answer: NO.
If you have shore power available, you can heat the water with only 120V. Be sure that the tank is filled properly BEFORE turning on the power, though, or you'll quickly fry the heating element.
If no shore power, you can use 12V only and burn propane to heat the water. No worry about frying an element.
With shore power, you can actually use both systems to get faster heating of the water if there is a high demand. Especially useful if more than one person wants to take a shower in a short period of time.
BTW, the OEM Hi-Limit switches are made for 130 degrees maximum. 140 degree ones are available, though.
This assumes that you have a Suburban DSI Water Heater, not an Atwood.
If you have shore power available, you can heat the water with only 120V. Be sure that the tank is filled properly BEFORE turning on the power, though, or you'll quickly fry the heating element.
If no shore power, you can use 12V only and burn propane to heat the water. No worry about frying an element.
With shore power, you can actually use both systems to get faster heating of the water if there is a high demand. Especially useful if more than one person wants to take a shower in a short period of time.
BTW, the OEM Hi-Limit switches are made for 130 degrees maximum. 140 degree ones are available, though.
This assumes that you have a Suburban DSI Water Heater, not an Atwood.
For some reason if I don't have them both flipped on I don't have hot water, if I turn off the 12V and leave the other on I don't have hot water and yes I waited about 6 hours before checking and water was lukewarm. When we say on the little lights are on right, with the flip switched up?
JohnD
Moved on to the next thing...
Have you closed the hot water tank bypass?
If not that could explain the luke warm water as it will mix hot and cold water to the faucets.
dbbls59
Well-known member
This was my thoughts too.
mlpeloquin
Well-known member
There is a 120V shut off switch in the water heater compartment. It has a rubber waterproof boot around it. If you have a Suburban water heater it should be lower left.
JohnDar
Prolifically Gabby Member
Piperflyer
Well-known member
Both switches have to be in the on position for the 120v to work. The one 120v in the coach and the 120v at the heater itself.
JohnDar
Prolifically Gabby Member
If he's connected to 120V shore power, he'll have the 12V for the circuitry supplied by the converter. Unless there is something else wrong, like the bypass or the outside shower valve open, he should get hot water either way. To answer his question again, he does not need both (meaning the gas heating system engaged along with the 120V element) to heat the water.
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Sent from my iPad using Tapatalk
danemayer
Well-known member
It seems like the question is about whether the electric element side of the water heater is working. If the water gets hot when the 12V/propane side is ON by itself, but not when the 120V side is on by itself, there are a number of possibilities.
First off, if this is a Suburban water heater, the secondary switch on the outside of the water heater could be OFF. That only prevents the electric element from getting power.
Secondly, on a Suburban, there are separate thermostats for 12V/propane operation and 120V operation. And the thermostat/ECO assemblies each have a reset button. The ECO might have tripped, requiring a reset.
Third, whether a Suburban or Atwood unit, the electric element could be burned out.
Fourth, there could be a power interruption somewhere.
If you have a Suburban water heater, consult our owner-written Water Heater Troubleshooting Guide for pictures and step-by-step directions to figure out what's wrong.
Incidental to the OP's problem, the discussion earlier in the thread touched on whether 12V DC power has to be available to the water heater for the electric element to work. On an Atwood unit the answer is yes. The Atwood control board operates both the 12V/propane and 120V thermostats and control circuitry. On the Suburban units, the answer is generally no, but if Heartland used 12V DC switches or other controls, and I think they have in recent years, the relays or other devices need 12V DC in order to sent 120V AC to the water heater.
And the mid-2017 Landmark 365s have a KIB control system that needs 12V DC to operate the water heater controls.
First off, if this is a Suburban water heater, the secondary switch on the outside of the water heater could be OFF. That only prevents the electric element from getting power.
Secondly, on a Suburban, there are separate thermostats for 12V/propane operation and 120V operation. And the thermostat/ECO assemblies each have a reset button. The ECO might have tripped, requiring a reset.
Third, whether a Suburban or Atwood unit, the electric element could be burned out.
Fourth, there could be a power interruption somewhere.
If you have a Suburban water heater, consult our owner-written Water Heater Troubleshooting Guide for pictures and step-by-step directions to figure out what's wrong.
Incidental to the OP's problem, the discussion earlier in the thread touched on whether 12V DC power has to be available to the water heater for the electric element to work. On an Atwood unit the answer is yes. The Atwood control board operates both the 12V/propane and 120V thermostats and control circuitry. On the Suburban units, the answer is generally no, but if Heartland used 12V DC switches or other controls, and I think they have in recent years, the relays or other devices need 12V DC in order to sent 120V AC to the water heater.
And the mid-2017 Landmark 365s have a KIB control system that needs 12V DC to operate the water heater controls.
Piperflyer
Well-known member
Thermostat could be defective too. Had to replace mine after 1 yr use
