Found the following in documentation for the Girard heater.
If the ECO is tested open by the control board when the hot water faucet is turned on then the control panel will show the water flow symbol and an E3 fault. The fan will not turn on.
If the water temperature reaches approximately 140 degrees during operation then the E3 code will show on the control panel and then the burner will turn off immediately and the fan will turn off after approximately 15 seconds. The E3 fault code will stay on the control panel until the hot water faucet is turned off and turned back on again or the board is reset.
Two Fault codes are generated if overheating conditions occur.
E3: ECO open before ignition or during normal operation.
This occurs if the ECO thermostat opens. Under normal circumstances this is due to the Temperature of the water at the Outlet exceeds 140 F. The cause must be identified and removed before restarting the unit.
E6: Over Temperature.
Outlet Water Temperature has exceeded 140°F (60°C) for 3 sec.
The main cause of overheating in this water heater is purging all of the air out of the plumbing and high temperature cold water coming into the water heater. Southern states in the summer time can get extremely warm water right out of the ground. When these conditions occur ensure that your water flow is proper.
Input and Output Thermistors
The water heater is equipped with an input or cold water thermistor and an output or hot water thermistor. These thermistors will give the control board the actual temperature of the incoming cold water and the outgoing hot water temperatures. The board will adjust the BTU’s to the gas valve to meet the requirements of the set temperature of the UCP.
The operating temperature shown at the UCP is the temperature of the output (Hot) thermistor.
If the output thermistor is open when the board senses that the flow sensor is on then an E0 fault code will be given.
E0: Water Outlet Temperature Probe failure.
An open circuit or short circuit condition is detected: This could be due to an internal failure in the Temperature Probe or to a faulty connection (Wires)
If an E0 or E4 fault occur verify with a voltmeter that the resistance of the thermistor is not an open circuit or a short.
Girard GSWH-2 doesn't heat
Operating panel comes on shows flame, fan, water flow. Water barely gets luke warm. Checked flame it seems low. About 1/4" maybe 3/8" high. Flame is blue. Just doesn't seem high enough. Anyone know how to adjust it? TIA Ken
Hi, I have a 2018 Axis 25.2 with a Girard Products GSWH-2 tankless water heater. We are on its second trip since new. Went to use the hot water tonight to clean dishes while 100's of miles away from home and getting a E5 error code on the display. Worst part, no hot water. Any ideas? Thanks.