Tankless Water Heater not Working - Need Help

[mondaymorn]

Hi!
So... Central California had a hard freeze the night before last. I left my cold water dripping to keep pipes from freezing and it seemed to work... woke up in the morning, turned on cold water and had no issues. BUT, I then turned on the hot water worked for a few seconds, then started sputtering hot steam... so I immediately turned it off. Waited a minute, turned back on... nothing came out. Turned on cold water, ran it for a minute, turned on hot water... stayed cold. Turned off cold, water still ran but ran cold.
Now its just normal flow, but cold. I hear the heater running, but its not heating the water. Checked the unit and from a physical inspection nothing seems to be wrong, no burning smell, melted wires, cracked pipes, etc. It is a Watt 15,000 btu tankless heater... I really don't have the money to replace it and am praying I am missing something that someone here may be able to point out. I can email pictures of the unit... can't seem to attach them here. The red plastic component is what I hear running, but it does have somewhat of a ticking sound to it... not sure if it made the same sound before.
Any and all input and ideas would be tremendously appreciated. Also, how do I prep my 5th wheel for those rare nights the temp drops below freezing? Do I have to do the whole antifreeze thing every time... even with the heat running?
BTW, I have a 2006 Outback Sydney 28FRLS... the heater is obviously aftermarket 🙂

[Sawdusty]

Allen8106 is correct with his information. I have the same water heater. Just leave the switch on and the propane on and the heater will come on for a few seconds every once in a while to keep the cubicle warm. There is also some heat tape around the paddle wheel in the incoming water line that has to be powered by 120v/ac.

[allen8106]

On page four it also says it has built in freeze protection.

Winter Operation and Winterizing Water Heater
This heater is equipped with freeze protection that will
prevent freezing under most conditions. In order for it to
function, 12 VOLT AND GAS SUPPLY MUST REMAIN
TURNED ON. This allows the burner to fire and electric
elements to protect the system. Any freezing of the
water heater or other plumbing components can cause
severe damage that is not covered by warranty.

[jus2shy]

Looking at the diagram, it appears that he probably froze the water inside the water heater. Running a slow drip on hot may help, but you have to remember you have a lot of surface area in contact with very little water, so the cold will more easily freeze a tankless unit. I was hoping to see a "Winter" or "Frost" mode for an RV tankless like I have for my home tankless water heater. Unfortunately it looks like it doesn't. My vote is that he simply just froze up.

[wgriswold]

liberty2010 wrote:
My guess is with water running through it all night the igniter may have burned out or the contact is coated with 'effort' from trying all night.

The OP said that water was running from the cold water. From what I know about on-demand water heaters a slow drip will not activate the heating cycle. There has to be a substantial flow as a safety feature. I wonder if a fast drip might protect the heater and pipes during a freeze?

[liberty2010]

My guess is with water running through it all night the igniter may have burned out or the contact is coated with 'effort' from trying all night.

[shadoow]

here's a link to the model he's got. Scroll down the page a little and there's a link to the Installation/Owners manual which has a troubleshooting section.

[TakingThe5th]

I'm not an expert on your particular water heater but I would hesitate to run the unit unless I was certain it had some water in it. You might damage it or even melt something if you run it dry.

[wgriswold]

Hot water pipes, and the pipes leading to the water heater, will often freeze before cold water pipes because the hot water is not used during the evening and at bedtime will contain water that is colder than the cold water pipes which are used in the evening.

Perhaps the delivery pipe to the water heater have frozen. One can help prevent this by running the hot water before going to bed. Better yet insulate the pipes and also run them.

[shadoow]

do you have the installation/operation manual? There's a section on troubleshooting that may help you.

[mondaymorn]

It is a precision temp RV-550...