I have a new to me, 2010 Newmar Dutch Star 4369. It comes with an on-demand tankless water heater. It has been parked the past week, hooked up to a 30 amp service. I have had both the electrical and propane switches to the water heater turned off. Just for the heck of it I turned on the hot water at a faucet and got...hot water. How does that work?

Does it have an Aquahot system? Could be from that

Mr. Bob, I would think that if you want it truly off, you need to flip the breakers for it. I assume that when you say 'switches' that you are just talking about the 'on/off' switches.I have a tankless water heater for our shower, I have to turn the breaker off for it not to heat. We also have an electric hot water tank that us sufficient for us if I need to watch electric power. The 'tankless' will pull some amps.Safe travels,MM.

1. You need to post the BRAND and model number of the Heater. Newmar used Oasis for LP and 120 heating2. Did you start the chassis engine and run it at anytime before you checked the faucet? Oasis has a engine heat option and that will heat the tank if the engine has run long enough to get to operating temp. Doug

By that year Dutch star should have a standard oasis diesel hydronic heat shouldn’t it ? I guess you could call it tankless but not boiler-less. Don’t have a oasis but lots of info ( google) if you have that. My Aqua hot heats by the engine , diesel or electric and because it’s well insulated keeps “warm” water for hours. It’s not tankless as mine has a 15 gallon boiler the coiled hot water line runs through (around in my case)

bobkatmsu wrote:I have a new to me, 2010 Newmar Dutch Star 4369. It comes with an on-demand tankless water heater. It has been parked the past week, hooked up to a 30 amp service. I have had both the electrical and propane switches to the water heater turned off. Just for the heck of it I turned on the hot water at a faucet and got...hot water. How does that work?You answered your own question. Obviously the "on-demand" system is still on and responding to your demands.Chum lee

How do I have hot water? | Good Sam Community

23 Replies

gonesouth
Explorer
Apr 21, 2018
I've got to say thanks to Doug for taking the time and effort to figure this out. I like to think I'm an expert on Aquahots and I've repaired one that had been frozen and left as a box of parts, but I sure didn't see this one coming at the start of the thread.

Kudos, Doug!
bobkatmsu
Explorer
Mar 25, 2018
jorbill2or wrote:
It’s obviously that the oasis died as Doug said and they decided to save a few bucks putting in the precision temp in its place. You have a puzzle to figure out how they wired it .. hopefully with a breaker somewhere. Hydronic heat has registers that are normally in baseboard cabinets etc. I’d bet they used the oasis original ones and just plumbed them in.
Are you the second owner? If you are the guy who sold it to you was playing dumb.
yes, second owner.
jorbill2or
Explorer II
Mar 25, 2018
It’s obviously that the oasis died as Doug said and they decided to save a few bucks putting in the precision temp in its place. You have a puzzle to figure out how they wired it .. hopefully with a breaker somewhere. Hydronic heat has registers that are normally in baseboard cabinets etc. I’d bet they used the oasis original ones and just plumbed them in.
Are you the second owner? If you are the guy who sold it to you was playing dumb.
bobkatmsu
Explorer
Mar 25, 2018
dougrainer wrote:
bobkatmsu wrote:
Does not have a furnace! I hadn't even looked for it yet as it hasn't been an issue living in Florida. Used the heat pump a few times and that worked fine. Do not know if it had hot water heater. Newgle is telling me it could have been made with a 10 gal hot water heater or the Oasis system.

If NO furnace, it came with the Oasis system. At sometime he must have frozen the Oasis and replaced it with the Precision Temp system. When you freeze a Hydronic system, you have destroyed it and will need replaced. The Precision and Oasis will utilize the same hook ups. The only difference will be how the system is controlled from inside the RV. If you had a Hot Water Heater, Sorry, no such thing. If you had a (cold):W WATER Heater, then you would have a HOLE in the side of the RV, usually on the drivers side in a DSDP. Hole about 15 to 18 inches square. As I stated, The Precision temp website is horrible as it does NOT show operation or the remote wall switch. If the website DOES show it, it is very difficult to find it. Doug
Nothing like that on either side of motor home.
dougrainer
Nomad
Mar 25, 2018
bobkatmsu wrote:
Does not have a furnace! I hadn't even looked for it yet as it hasn't been an issue living in Florida. Used the heat pump a few times and that worked fine. Do not know if it had hot water heater. Newgle is telling me it could have been made with a 10 gal hot water heater or the Oasis system.

If NO furnace, it came with the Oasis system. At sometime he must have frozen the Oasis and replaced it with the Precision Temp system. When you freeze a Hydronic system, you have destroyed it and will need replaced. The Precision and Oasis will utilize the same hook ups. The only difference will be how the system is controlled from inside the RV. If you had a Hot Water Heater, Sorry, no such thing. If you had a (cold):W WATER Heater, then you would have a HOLE in the side of the RV, usually on the drivers side in a DSDP. Hole about 15 to 18 inches square. As I stated, The Precision temp website is horrible as it does NOT show operation or the remote wall switch. If the website DOES show it, it is very difficult to find it. Doug
bobkatmsu
Explorer
Mar 25, 2018
Does not have a furnace! I hadn't even looked for it yet as it hasn't been an issue living in Florida. Used the heat pump a few times and that worked fine. Do not know if it had hot water heater. Newgle is telling me it could have been made with a 10 gal hot water heater or the Oasis system.
dougrainer
Nomad
Mar 25, 2018
https://precisiontemp.com/wp-content/uploads/2018/03/Twin-Temp-2-and-Jr-Installation-Manual.pdf

Click and look at the install. You will have numerous Hot water lines run thru out the RV for the Furnace zones. IF those hose parts are not used at the units and blocked off, he spent a LOT of money for a Water heater. Do you know if the original unit had a Water Heater or the Oasis system? He may have had the Oasis and replaced with the Twin Temp which would work with the Zone furnace radiators of the Oasis. IF you have a LP powered Furnace, then the unit did not come with a Hydronic system. Doug
bobkatmsu
Explorer
Mar 25, 2018
I do not see anything that would lead me to believe I have hydronic heating and the previous owner says no, but I have learned he did not know much about his unit. What should I be looking for if I had hydronic heating. Also there IS NOT a twin temp switch in the motorhome, but there is one on the side of the unit.
bobkatmsu
Explorer
Mar 25, 2018
I do not see anything that would lead me to believe I have hydronic heating and the previous owner says no, but I have learned he did not know much about his unit. What should I be looking for if I had hydronic heating
rogerddd
Explorer
Mar 25, 2018
What Doug said. "TRUE Tankless RV water heaters CANNOT utilize 120 volts to give continuous HOT water." Mine starts warm then cycles between warm and cold. That's if we are hooked up. Dry camping presents different (worse) issues.