If your 40H/HI has been working fine but is now having issues, ask yourself this question: What has changed? There are a few basic things which can affect the operation of a tankless water heater, which are listed below.
1. Clogged filter screens
2. Low water flow
3. Single knob faucets
4. Incorrect gas type or gas pressure
5. Low or empty gas tanks
6. Issues with the electrical supply
7. Recent power surges (i.e. lightning)
8. High temperature setting
9. Blockage in the exhaust
If any of these things seem possible, then please check to see if it applies through troubleshooting prior to calling customer service.
The first and most important thing to do is to make sure the gas being supplied to the water heater is correct for your model. There is a plate on the side of the water heater which will provide the gas type that it was designed to be used with. This plate will either say NG for Natural Gas or LP for Liquid Propane. Do not run your water heater with the incorrect gas type.
Make sure the temperature is set to 120 degrees or below. The 40H/HI will overheat with low water flow. If this is happening, remove any filter screens that are installed in your faucets and see if that alleviates your problem.
40H/HI is experiencing issues, but only at one faucet:
Is there anything different between this faucet and the other fixtures that are working properly? Usually this is attributed to too little or too much water flow. Specifically if the water heater is overheating or shutting down during operation, check the filter screen in your faucet and free up your water flow as much as possible. This can also be directly related to the faucet being a single knob faucet. Again, free up your water flow as much as possible.
40H/HI will not turn on and doesn’t have anything on the display:
If your water heater does not show anything on the display and will not run, you most likely have an electrical issue. Check to make sure that the main breaker supplying power to the outlet is not tripped. Also, if the power outlet that your water heater is plugged into has an incorporated breaker, make sure that it is not tripped. A very easy way to test to make sure the outlet is working correctly is to plug a different electrical appliance into it and see if it will turn on.
After verifying that your water heater has power going to it, you can check the internal wire connections. First, unplug your water heater from the electrical outlet. After doing so, remove the cover by taking out the four screws on the front which hold it in place. On the indoor models the digital display is attached to the cover, so please be careful as to not damage the connections. Once the cover has been removed, check the wire connections throughout the water heater to make sure everything is plugged up and secure. If it looks like there is a build-up of corrosion, unplugging and re-plugging the connections verify they are correct. Note: the computers are interchangeable between the indoor and outdoor models. The main difference is that the indoor models connect directly to the computer board and the outdoor models connect to a set of green wires coming from the computer board. On the 40HI, there will be a green wire that is not connected to anything and on the 40H there will be a wide white ribbon wire that is not connected to anything. This is perfectly normal.
Lastly, if you then test your water heater and it does still will not come on, you will need to remove the computer board and check to make sure the fuses are intact. Again, make sure that you have unplugged the power cord so there is no electricity going to it. Inside, there is a grey box that is located near the top right. Remove the two screws from the front of the board and it will slide out freely. On the computer board you will see two rubber boots which cover and protect the fuses. Pull these boots off and, if the fuses are still in working order, there will be a thin wire that is visible inside of them and should not be broken. If the wire is broken, you will need to replace the fuse.
40H/HI is displaying set temperature, but will not come on:
This means that your water heater is not seeing that there is water flowing through it. The most common reason for this is low water flow. To determine if this is the case, turn on two faucets and see if your system turns on. If this works, you probably have clogged filter screens. Check all of the filter screens in your faucets to see if they have become clogged over time. If you remove the filter screen from a faucet, turn on the hot water at that location, and the system runs, you can always just not reinstall the screen and use the faucet in this manner. Next, check the filter screen that is in the water heater itself. There is a drain plug where the inlet water pipe enters the water heater. There is a screw located on the front of the plug, inside of it. Do not try to loosen or tighten this screw. The entire drain plug will unscrew and can be removed. Once removed, you will see a filter screen with a magnet in the center of it. If dirty, they can both be cleaned by gently using a wire brush. If you need a new filter screen, you can order one from our website at www.eccotemp.com.
Lastly, you will need to check your flow sensor to verify that it is working properly. If you see the attachment to this tope will find a Flow Sensor Installation Guide which will help in completing this task. Follow the instructions in the guide to remove the flow sensor. Once removed, you can blow through the flow sensor to verify that the impeller inside of it is spinning freely and there is no debris inside of it. Reinstall the flow sensor as the guide instructs and test the water heater.
If these steps do not work, please contact technical support at 866-356-1992.
40H is showing two rotating squares:
This means that the water heater has been turned off either by pushing the power button or the power was lost somehow while it was running. This can be resolved by simply turning the water heater back on with the remote.
If this does not fix your issue, please contact technical support at 866-356-1992.
Please see the attached guide to aid in removing and installing a flow sensor for the 40H and 40HI.