Troubleshooting A Fogatti Tanjless Water Heater That Goes Cold But Doesn't Have An Error Code

Updated 01/03/2025 | Published 06/27/2023

Products Featured in This Question

Digital Multimeter with 42" Long Test Leads - LED Display

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Seaflo Accumulator Tank for RV and Boat Water Pumps - 0.75 Liter

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Seaflo Diaphragm Pump for Boats and RVs - Variable Flow - 3 GPM - 45 psi - 12V DC

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Question:

I have installed a 2.2 gpm Fogatti Tankless Water heater. When I turn on the hot water, the heater heats the water, but it gets hotter and hotter, I see the temperature on the controller go above 50 celsius, then the water stops being heated and begins to cool off to a lower temp. The water pump in the camper is a 45 psi pump, Im think that I have more than 1 gpm flow. The cold water is straight from a well pump, maybe 50 degrees F. There are no codes on the controller, it seems to be working otherwise.

asked by: J.P. C

Expert Reply:

If the hot water from your Fogatti RV Tankless Water Heater # LSB64FR is fading back to cold it could be for the following reasons:

If you have a lack of lp gas pressure the unit won't be able to keep up. Typically you would get an error code with this. Since you're not it leads me to believe that it's either a water pressure issue or electrical issue.

Check the water pressure at the unit to ensure it's getting around 40-50psi so that it can keep up with the demand at the point of use (faucet). A normal water pump will typically have a 40-50 psi and 3.0gpm rating, like part # SE58FR does. You can also add in an accumulator tank # SE38FR to help maintain pressure. I also wonder if you experience this issue when connected to city water? If not then it most likely is that you pump can't keep up.

Check the voltage at the unit with a multimeter # PT89ZR to ensure the controller and the main unit are getting 12 volts to properly function. If the voltage is fine and nothing else has solved the issue then the controller or the internal thermostat is faulty and you'll need to reach out to the manufacturer for a warranty replacement.

expert reply by: Kevin C

Tammy

1/3/2025

I ran out of propane which made a E1 error. I hooked up full tanks and still wasn't getting a good flow to my stove. Replaced the regulator and now have good flow to stove. No E1 error on water heater but it won't get hotter than 96 degrees even when I have it set on 116 degrees. I shut off power and waited then tried again still won't get above 96 with shower running. With shower running I turned on the sink and temp dropped to 86 degrees. Turned off sink, temp went back to 96 won't go higher. I tried setting temp to 120 still only 96 I set temp to 110 still only 96

Kevin C.

1/3/2025

@Tammy If the unit isn't reaching the set temperature then it could be faulty inlet/outlet temp probes, water flow sensor, or thermostat. Unfortunately these parts can only be purchased through the manufacturer so you'll want to reach out to Fogatti to see if the walk you through testing to see which part needs to be replaced and then get you the part.