The Tankless Water Heater Problem Saga Continues

[hduring]

We’ve written before about issues with the TWH on our 337. Our RV came with a Furrion, that broke due to not winterized correctly. Got a Girard replacement, that broke, stopped heating. Wanted a Truma (RV repair shop is authorized to install these but price was high), but got a Fogatti. Common problem with the 3 TWH’s we’ve owned is you set the temp on the panel (almost dummy proof instructions) for example to 96 degrees, and then shower, and the water gets really hot and the panel shows 124 degrees and climbing (123 degrees is max we can set it), so we then turn on cold water (no cold water turned on before that) and that shuts off the TWH (you can hear it)and the water naturally gets colder, so then you turn off cold water and hear TWH starting again, maybe to around 114 degrees and stays there - still too hot for us. So has us thinking this has to be user error although we’ve seen other posts from GD owners complaining about the same thing. We know many folks have no issues and enjoy their TWH, but we really despise these devices. We are happy to say that we have had no other issues with our 337 since purchase. You can’t contact these companies or send them Emails - they don’t respond (at least not for us), there’s not many adjustments on these devices either or you cannot get to them easily, and although we go camping throughout Colorado, we are always below 8000 feet (Fogatti rated to 9800 feet). Our previous non-GD TT had a tank water heater and we had no issues with that device and getting hot water, and at a decent temp. So what’s the secret to getting the TWHs to stay at the temp we’ve set?

[howson]

hduring

I know little about the devices (specifics). Based on what I read in the manual (I assume it's this one: https://drive.google.com/file/d/1Bdd...OzO7O6pVz/view ) it seems like the "intelligent control system" is, well, not very intelligent.

From the manual: The water heater is designed with intelligent control system. Simply set the temperature and press the start button for rnachine detecting the qualify water flow. After ignition, the gas valve invites propane to ignite the burner, then runs steady hot water.

While I'd normally suspect the thermostat, that seems to be working since the wired controller appears to be accurately reflecting the actual temperature. (Easy to verify with a meat thermometer--immerse in a glass filled with hot water.)

In other words, seems like a main control board failure to me based on the symptoms and what little I can glean from the manual. Could be way off--just an educated guess.

Try giving Dinosaur a call. They are usually really good at diagnosing issues (if they make a board for the Fogatti). https://www.dinosaurelectronics.com/

Howard

[hduring]

hduring

I know little about the devices (specifics). Based on what I read in the manual (I assume it's this one: https://drive.google.com/file/d/1Bdd...OzO7O6pVz/view ) it seems like the "intelligent control system" is, well, not very intelligent.

From the manual: The water heater is designed with intelligent control system. Simply set the temperature and press the start button for rnachine detecting the qualify water flow. After ignition, the gas valve invites propane to ignite the burner, then runs steady hot water.

While I'd normally suspect the thermostat, that seems to be working since the wired controller appears to be accurately reflecting the actual temperature. (Easy to verify with a meat thermometer--immerse in a glass filled with hot water.)

In other words, seems like a main control board failure to me based on the symptoms and what little I can glean from the manual. Could be way off--just an educated guess.

Try giving Dinosaur a call. They are usually really good at diagnosing issues (if they make a board for the Fogatti). https://www.dinosaurelectronics.com/

Howard

Thanks Howard. We’ll contact Dinosaur. Maybe it is as simple as a main control board issue, but could we be that lucky (unlucky) to have main control board issues on the Furrion, Girard and now the Fogatti TWH since we had the same issue on three different water heaters with temp fluctuations? Each TWH came with their own wired controller, but the temp adjustments are basically all the same.

[Country Campers]

Have you thought about having a tank water heater installed? They are still available and I believe will fit in where a tankless was.

Brian

[hduring]

Have you thought about having a tank water heater installed? They are still available and I believe will fit in where a tankless was.

Brian

I asked our RV repair shop, and we were told that the compartment was too small to house a tank water heater. Interesting though that our internal main controls (lights, awnings, tank gauges) show two slots that are covered which we can guess are for hot water heater on/off switches (gas/electric). Do you think Grand Design could answer the tank water heater question?

[Country Campers]

They may be able to answer that. Measuring the tankless water heater or even the opening will let you know if it will fit or not. I will check the drawings that I have access to and see if I see some dimensions that may help.

Brian

On edit: The drawings I have are dated 2013. I am pretty sure not much has changed but there is always that chance. Contact GD and see if they can give you the information needed.

[ncitro]

hduring Not much help here other than to say I have the Truma and I'm very happy with it. I had a Dometic/Atwood tank water heater as the Truma fit exactly in it's place. I was also under the impression it was a standard opening except for the big Suburban unit (12 gallon I think).

[Jlawles2]

What I have noticed with the Furrion tankless and water temps are just as described.

To me it sounds as if you are not flowing enough water through the unit for it to control the temps. I can replicate the exact condition as described by cracking the hot water just enough to activate the heater, then adding cold water to it, or by not flowing enough water with just the hot turned on.

Trick, set the water temp where you want it and turn just the hot on in the shower to FULL open.

In the mean time, check you regulator and supply hose to the unit along with the supply hose filter screens. You may also want to check the supply pressure to ensure it is not dropping too far (this would indicate a low flow supply pump from the source or restriction somewhere up stream of the gauge).

[howson]

Jlawles2 -- your input about low flow through the heater could also explain why there's been issues with three separate TWHs. I agree that verifying flow rate through the water heater should be the first troubleshooting step--makes more sense than first going for the main board.

I looked for an adjustment (like there is on the Furrion) for flow rate but didn't see it. hduring -- do you know if the Fogatti has a water flow adjustment knob? If it does, what it is set at?

Howard

[hduring]

Jlawles2 -- your input about low flow through the heater could also explain why there's been issues with three separate TWHs. I agree that verifying flow rate through the water heater should be the first troubleshooting step--makes more sense than first going for the main board.

I looked for an adjustment (like there is on the Furrion) for flow rate but didn't see it. hduring -- do you know if the Fogatti has a water flow adjustment knob? If it does, what it is set at?

Howard

Thanks for the insight Joseph Jlawles2 and Howard howson - we want to state that “for now” we will call this case closed as we are done camping for the next few months and won’t be touching the RV until next Spring. We’ll answer some of the comments/questions though and keep your ideas/suggestions handy for next year. Please however share any other thoughts you have. Howard asked about a flow knob, but the Fogatti has no water flow adjustment knob. Looking over the Fogatti user manual online, it shows info as follows (attached snapshot about temperature instability)

We have already tried the trick Joseph mentions, and how does one check supply pressure?
Should we start at our water regulator (45 psi, not setable and not new), and what is a water flow stabilizer (from user manual snapshot)? Also, not sure how to read this, but found this Altitude info on the instruction manual that Howard submitted above.

We just returned from camping at 7000 foot elevation (that‘s where we submitted this post), so could the 8+% decrease in gas rate have an affect to all this?

Thanks again for the info.

[Cate&Rob]

This is a classic example of where a system water pressure gauge would show exactly what is going on. hduring . . . such a gauge can be T’d into any cold water line. I have posted this idea many times before. See my National Rally Seminar for more details on this gauge. https://gdrvowners.com/rallies-aa/11...umbing-seminar

Rob

[TedS]

hduring that altitude illustration means that the gas should be reduced to correct the fuel-air mix at various elevations due to reduced air available at altitude. The gas flow does not automatically decrease with increasing altitude. Usually an orifice change is required to reduce the gas flow for the available air. Excess gas flow, or conversely insufficient air flow, would result in an improper burn and probably lower flame temperature.

[Jlawles2]

You can build a simple Tee fitting for the water hose using a couple of components available from the big box store. I run a gauged regulator to see the pressure downstream of the regulator as pressure drops on the back side mean more of a supply issue.

https://www.amazon.com/gp/product/B0...=UTF8&psc= 1

3x https://www.homedepot.com/p/Everbilt...1709/300095988 plus https://www.homedepot.com/p/Everbilt...1959/300096139 plus https://www.homedepot.com/p/Melnor-M...B-HD/206480253 plus https://www.homedepot.com/p/Watts-3-...IWTG/100175467

OR https://www.homedepot.com/p/Watts-3-...IWTG/100175467 plus https://www.homedepot.com/p/Everbilt...1639/300095982

I'd try to avoid the WYE fittings with valves as the valve is a major restriction in the water flow.

By chance have you tried running the shower off the onboard water pump?

[hduring]

You can build a simple Tee fitting for the water hose using a couple of components available from the big box store. I run a gauged regulator to see the pressure downstream of the regulator as pressure drops on the back side mean more of a supply issue.

https://www.amazon.com/gp/product/B0...=UTF8&psc= 1

3x https://www.homedepot.com/p/Everbilt...1709/300095988 plus https://www.homedepot.com/p/Everbilt...1959/300096139 plus https://www.homedepot.com/p/Melnor-M...B-HD/206480253 plus https://www.homedepot.com/p/Watts-3-...IWTG/100175467

OR https://www.homedepot.com/p/Watts-3-...IWTG/100175467 plus https://www.homedepot.com/p/Everbilt...1639/300095982

I'd try to avoid the WYE fittings with valves as the valve is a major restriction in the water flow.

By chance have you tried running the shower off the onboard water pump?

Joseph, thanks for that info/links. Never tried the shower off the onboard water pump, but worth trying.

[hduring]

This is a classic example of where a system water pressure gauge would show exactly what is going on. hduring . . . such a gauge can be T’d into any cold water line. I have posted this idea many times before. See my National Rally Seminar for more details on this gauge. https://gdrvowners.com/rallies-aa/11...umbing-seminar

Rob

Rob, thanks for that info. We’ll be getting one of those water pressure gauges soon, as well as a tee fitting.