Why Girard Tankless Water Heater Not Turning On [Fixed]

From my years of experience using and dealing with Girard tankless water heaters, I can confirm that the following are the major reasons behind your Girard tankless water heater not turning on:

  • Insufficient electric supply
  • Too low water flow rate
  • Gas supply problems
  • Tripped energy cut-off switch
  • Failed control board 

Above all, you may have an error code on the user control panel (UCP) that will shut off the unit until the related issues get resolved.

First off, check for a tripped circuit breaker and a blown fuse. Also, the heater power switch and the wiring should be in perfect working order. Next, double-check to make sure you have up to 1 GPM of water flowing through the system.

However, if the issue still persists after your efforts, I bet there will be a fault in one of the components in the heater. Now from my own experiences of troubleshooting the Girard tankless water heaters, let’s take a closer look and identify the potential faulty parts.

girard tankless water heater not turning on

Quick Overview With How To Fix Instantly

From my own experience, I’ve discovered that a few particular issues lead to a Girard tankless water heater not turning on. Here’s a list of potential reasons and their solutions I’ve found super effective:

Probable Reasons Recommended Fix
Electrical glitch # Reset the unit. 
# Replace the blown fuse and faulty heater On/Off switch.
Bad water flow # Make sure the water lines are connected from hot to hot and cold to cold.
# Remove the restrictor from the water lines.
# Clean out the water flow sensor. 
Gas supply issue# Make sure the fuel tank is filled with sufficient propane.
# Check for obstruction in the gas line.
# Inspect and replace the bad gas valve. 
Tripped ECO switch# Clean out the exhaust and air intake.
# Unclog the air filter screen to allow fluent airflow.
# Examine the blower motor and pressure switch function.
Defective control board# Replace the bad control board. 

Girard Tankless Water Heater Not Turning On [Causes + 7 Easy Solutions!]

In this section, I’ll share my first-hand experience on how you can diagnose the obvious reasons and how to fix the common issues that can cause your Girard tankless water heater not to turn on.

01. Reset Your RV Water Heater

If you find your Girard RV tankless water heater is failing to power on, there might be a minor glitch in the system. 

In such a scenario, based on my experience, I could discover that simply resetting your water heater is most effective and fix the not turning on issue most often. 

How To Reset Girard Tankless Water Heater?

Follow the below step-by-step procedure to reset your heater:

Step #1: Unplug your water from the power connection or disconnect the electric supply from the unit from the main electrical panel. Flip the circuit breaker to the “Off position”. 

Step #2: Turn off the hot water faucets for your water heater.

Step #3: Wait for 10-15 minutes. 

Step #4: After that time, turn on the hot water fixtures and finally, restore the power supply to your water heater.

Step #5: The controller of your water heater will be reset and the unit should turn on. 

02. Power Supply Issue

In my journey of troubleshooting, I’ve often found that if the water heater won’t turn on even after resetting the unit, an electrical glitch is the culprit. Sometimes, I could see a simple electrical issue preventing the heater from powering up properly. You should know a Girard tankless water heater requires up to 12 VDC of electric supply for proper operation.

So, if anyhow your unit won’t get that amount of electric power, your water heater won’t turn on. Remember that the water heater will not function when the input voltage drops below 10VDC. An illuminated Red LED on the control board signs you the voltage drop. 

Anyway, there are several factors that would be responsible for a faulty power supply to your water heater. Such as:

  • Tripped circuit breaker
  • Blown fuse
  • Worn-out electrical wiring
  • Faulty power cord connection
  • Insufficient voltage supply
  • Broken heater On/Off Switch

How To Fix:

Before you examine or touch any of the electrical wiring connections to any appliance, I strongly recommend turning off the power supply as the first safety precaution. 

When done, go through the below fixes for fixing the degradation in the power supply to your water heater:

First off, make sure your heater is connected to a 12V DC electric supply. You can go through a voltage test with a multimeter. Also, the electrical outlet should be functional enough to run your water heater. 

In case you are using an older converter for electric supply, I recommend checking out the wiring connection and battery voltage.

girard water heater power button & fuse

When done, remove the front panel and access the power switch and fuse as shown in the picture.

Make sure the switch is not broken and the fuse is in well working condition. Also, after plugging the heater, ensure that you have turned on the heater On/Off switch.

Besides all the above, look for faulty wiring connections in the heater inside and replace the worn-out ones. Tighten the loose wiring. I’ll recommend you contact a certified electrician if you don’t get enough electric supply.

03. Bad Water Flow

Insufficient water flow is one of the most frequent reasons why your RV water is not turning on after plugging in. Basically, Girard RV tankless water has a minimum water flow rate of 1 GPM to activate the unit. If the water flow is less than the minimum flow rate, the unit won’t turn on. 

Several reasons are to blame for insufficient water flow in the unit. That includes:

  • Clogged or defective water flow sensor
  • Restrictor in the water line
  • Water lines are connected wrong. 
  • Accumulated dirt and debris in the water supply lines.

How To Fix:

Here are all the needed troubleshooting steps to deal with bad water flow in your tankless water heater:

Step #1: Start by inspecting the water supply line for your water heater. You need to make sure that the hot water lines are connected to hot and the cold to cold.

Step #2: Then inspect the water line for any accumulated dirt and debris. If so, you need to clean it. Also, make sure there is not any water restrictor on the waterline. If you have, just remove it. Plus, purge all air from the plumbing system.

Step #3: Now measure the water pressure with a pressure gauge. It should give a reading between 1 and 1.4 Gallons per Minute to ensure the optimal operation of the water heater. 

If not, now try to increase the pressure from the pressure regulator (If you have one). In most cases, the water pressure regulator decreases water flow to unacceptable levels. So adjust it or better remove it.

Step #4: Above all, a bad flow sensor is also responsible for water flow restriction in the water heater. It is designed to give the actual water flow measurement to the control board. 

girard tankless water heater water flow sensor

Inspect the flow sensor and clean out the debris first. Replace the sensor if it is no longer in operating condition.

Step #5: Then inspect the water control valve adjustment on your water heater.

girard tankless water heater water control valve

Ensure that it is opened all of the way up. After ensuring all the above steps, you can ensure a fluent water flow to your water heater.

Step #6: Nonetheless, sediment buildup in the heat exchanger is also one root culprit that highly affects the water pressure and the flow rate. 

To fix these issues, you need to know how to descale the unit. You can do it by yourself by following this effective Girard tankless water heater maintenance guide or you can call a professional to do the best tasks for you.  

04. Gas Supply Interruption

Along with the electricity, your Girard tankless water heater requires an adequate amount of fuel to operate properly. Interruption in gas supply or poor gas supply is one of the major reasons why your RV tankless water heater is not turning on. 

Either you have an empty LP tank or there may be insufficient gas pressure from the tank. Other culprits would be:

  • Bent gas hose
  • The gas valve is not fully opened 
  • Obstruction in the gas line
  • Bad gas valve connection

How To Fix:

Start by inspecting the fuel tank to ensure there is enough propane for ignition. If not, refill it. After refueling the tank, don’t forget to purge all the air from the gas line. Then, make sure the gas valve on the tank is fully opened and there is no obstruction. 

Check for obstruction in the gas supply line as well.  At most times, debris and a build-up of oil in the LP plumbing can restrict gas flow in the system. Thus cleaning is a must.

While doing so, straighten the bent gas hose to let the gas flow freely. When done, check for gas pressure for your water heater with a manometer. It should give a reading minimum of 11” WC at the monomer.

Next, remove the front cover and inspect the gas valve from the inside. You will find an ON/off solenoid valve and a linear valve at the same gas valve assembly. 

Make sure they are in perfect working order. Measure the output gas pressure of the gas valve on the right side of the board as shown in the picture below:

girard tankless water heater gas valve

There should be 1.5” WC on low heat and 7.8” WC on high heat. If not, it’s confirmed that the gas valve is not functioning well. Either you need to adjust it or replace it. Hire a professional to deal with this issue.

05. Tripped ECO Switch

The energy cut-off switch is an essential safety element in an RV tankless water heater that is designed to cut off the power when the inlet temperature reaches 140 degrees. In such a way, it helps to prevent intermittent overheating and erroneous heating issues throughout the system.

The switch will constantly be tripped until the heater temperature goes down to the recommended level. In this situation, you can never expect to turn on your water heater even if there are no issues with the electrical connection. 

Now, to diminish the constantly tripped eco switch issue, you have to track down the responsive factors for the heater overheating. For convenience, here I’ve listed some major ones:

  • Blocked venting
  • Failed blower motor
  • Clogged air inlet filter screen

How To Fix:

i. Clean The Blocked Exhaust Venting

Inspect all exhaust and intake lines of your water heater for any stuck dirt and debris. Take a vacuum cleaner attached to an extension hose and remove the dust and pollen particles from the vents. If you find it hard to reach the hose into vents, you can use a duct cleaner as an effective alternative.

ii. Inspect The Blower Motor & Pressure Switch 

It’s worth mentioning that the malfunctioning of the blower motor is another leading culprit. You are struggling with a poor air supply in your tankless unit.

Unlike other RV models, Girard tankless water heater equips 4 wire variable speed brushless motors that are designed to operate with a 24VDC pulse width modulation system. 

If you suspect to have malfunction from the blower motor here’s all you can do to fix this element:

  • First, inspect the blower motor and check for debris in the assembly. Clean it with a soft microfiber cloth.
  • Then ensure a snug blower motor wiring connection (CN1) to the control board. Fix the loose wires.
  • Check the wiring connection of the pressure switch as it is an essential air-proving device on the water heater. Verify the switch hose is free of obstruction.
  • Now, inspect the Petit Tube connected to the pressure switch inside the blower housing. Check for integrity in the petite tube, also make sure the tube mounting nut is firmly attached. It should be facing away from the blower wheel. 

If you find it difficult to fix the blower motor and pressure switch issue, I suggest you contact a professional.

iii. Clean The Air Filter Screen

Besides all the above steps, don’t miss to inspect the air screen inlet. Clean out stuck dirt particles from the screen using a wire brush.

06. Failed Control Board

If still, your tankless water heater isn’t turning on even after fixing the gas, air, and electric supply issues, be sure you are dealing with a failed control board The water Heater equips a microprocessor-based controller that functions by receiving operational parameters from the User Control Panel (UCP).

girard tankless water heater control board

As with other electronic components in the heater, it’s not uncommon to have defection in the control board. This mainly occurs due to a faulty wiring connection between the control board and the UCP.

How To Fix:

If you have no power to your heater even after fixing the wiring issues, then it’s confirmed that the control board is bad and you need to replace it. Contact Girard customer service for the control board replacement part for you. 

07. You’re Getting An Error Code On The Controller

While operating the water heater, it’s a quite common phenomenon that the user encounters several diagnostic error codes at the UCP. Basically, when the controller triggers any unsafe condition within the system, it shuts off the unit with an Error Code corresponding to the actual condition that is causing the unsafe condition. 

The best chances are if your unit is not turning on, there may be an error in your control display. If so, be sure it is time to track down the actual indication of the appearing error code and fix it.


How long will my RV tankless water heater last?

With proper maintenance, you can expect to use your water heater for up to 20 years. But in the meantime, you may encounter various defective heater parts that need replacement. If it is under warranty, contact customer service for the replaceable parts.

What does the illuminated LED indicator light mean on the Girard RV control board?

If it is a red light on the board, it signs that the voltage dropped below 10VDC and the heater stops functioning. Voltage above the 17 VDC illuminates the green LED, indicating the heater is in perfect working order.

What is the recommended temperature level on Girard RV tankless water heater?

Girard RV water heater equips a UCP on which we can set temperature from 95° (F) to 124° (F). But it’s always better to keep the temperature level within 115° (F).

In Closing

When you are almost ready to use the hot water, nothing is more annoying than your Girard tankless water heater not turning on. Without considering any other facts, start troubleshooting by inspecting the faults in the electric supply and fixing those. I’ve broken down all the effective troubleshooting actions to turn the unit on and to get the comfy hot water again. 

To ensure optimal performance from your water heater, always concentrate on the proper maintenance of your Girard tankless water heater. You can check out our guidelines about maintenance that is linked in the “bad water flow” section above.

Anyway, we’re almost to the end! But before leave, I recommend our comprehensive guide on why Girard tankless water heater keeps shutting off, in case you face such an issue with your heater. We’ll be glad to see you there again.

Good Luck!

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