Girard Products GSWH-2 Technical Manual page 12

Once the board senses water flow then the board will read the ECO to ensure it is not open.
The wire connections on the ECO are clip type spade connections. Pull back the insulation over the spade connection and
push the clip down and pull simultaneously.
ECO
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.
Verify wire connections are good.
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.
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