Girard Tankless Water Heater No Hot Water [What To do]

The leading reasons behind Girard tankless water heater no hot water include:

  • Bad water flow
  • Interruption in the gas supply
  • Power supply issue
  • Wrong adjustment of the anti-scald valve 
  • Or, the bypass valves may be set incorrectly 

Also, if you have an issue with the igniter and burner assembly, the heater fails to deliver hot water as you demand.

To ensure the maximum heat from your RV water heater, check and adjust the water pressure of your unit. Also verify there is sufficient fuel in the tank and the gas valve is fully in the ON position. In case your system is overloaded, you have to let your water heater reset.

Read on and find out why you’re running out of hot water in your RV heater and what to do about it.

girard tankless water heater no hot water

Quick Overview & Solutions To Girard Tankless Water Heater No Hot Water

If you are in a hurry, go through the solutions in the table below to fix your heater’s lack of hot water issue.

Probable Reasons Recommended Fixes
Bad water heater # Check to make sure the inlet flow valve and water shut-off valve are opened all the way.
# Remove the flow restrictor from the water lines if you have any.
# If the water pressure is too high, adjust hot water fixtures to slow down the water-flowing rate. 
Gas supply issue # Ensure you have sufficient fuel in the tank. 
# Inspect the gas supply lines for any obstructions. 
Wrong adjustment of the anti-scald valveInspect the anti-scald valve in the shower handle and turn it to the hotter side. 
Power supply issue Check for loose wiring connections and fix them. Make sure the heater’s ON/OFF switch and fuse are in perfect working order. 
System overload Close the extra hot water fixture to meet the heater’s simultaneous hot water demand. 

Girard Tankless RV Water Heater Not Getting Hot Enough [Reasons + Proven Fixes]

Now take an in-depth look at all possible reasons why your RV tankless  water heater is not getting hot enough with effective solutions:

01. Bad Water Flow

If you are getting lukewarm water or not hot water at all, bad water flow throughout the unit is the root culprit to blame here.  A minimum flow rate of 1.0 Gallons per Minute (GPM) is a must to have proper operation from your tankless water heater. 

If the water flow is not in the range of this listed GPM you won’t have enough hot water at peak use times.

Now, come to the point! When you have a hot water issue due to the malfunctioning of the water flow, there would be two scenarios to concentrate on. 

Either you have too low water flow or the water pressure is too high throughout the unit. Both factors are responsible for the issue.

If the water pressure is too low, it bypasses the heater’s minimum flow rate & the water heater turns off, and the complete heating functions. On the contrary, if you have high water pressure, it is pushing more water into your tankless unit than it can adequately heat.

Well, now let’s preview all possible factors that cause bad water flow to your tankless water heater:

  • Water shut-off valves are not open all the way
  • Obstructions in the water supply lines
  • Clogged water flow sensor 
  • Wrong adjustment of the water flow restrictors in the water lines
  • The water pressure regulator is wrongly adjusted

How To Fix:

Before heading to any decision, your first duty would be measuring the water pressure to your RV tankless unit. I bet you are quite familiar with it! 

Take a water pressure gauge and connect it to the drain valve or flow inlet valve on the back of the RV unit.

flow inlet valve of girard rv water heater

Open the valve all the way and this will give you a pressure reading of your tankless unit. If you have a major difference in the reading from the recommended level, it’s time to adjust the pressure:

i) Adjust The Low Water Pressure:

  • First off, head to the water shut-off valve and hot water fixtures. Open them all the way.
  • Check whether there is any flow restrictor installed in the water lines. If so, remove or adjust it properly.
  • In case you are using a water pressure regulator to adjust the water pressure, you should adjust it properly as well. 
  • Inspect the water pipes for any obstructions. Clean it to ensure a fluent water flow. Besides, purge the air from the plumbing system. You will also strain the screen at the water inlet to the back of the unit which can become blocked with debris. So, remove this strainer and clean it properly. 
  • Above all, don’t forget to verify the water flow sensor condition as it is the crucial part to give the actual water flow measurement to the control board. Clean it or if needed replace it.
  • Turn down the water temperature to match the shower temp you want to take. If it is set too high, you won’t demand enough hot water as the heater mixes cold water on the basis of that. Turning up the temp too high further reduces the demand that turns off the heating process.

ii) Adjust The High Water Pressure

  • Adjust the water shut-off valve and hot water fixtures to slow down the water-flowing rate in the unit.
  • Also, you can install a flow restrictor or water pressure regulator to lower the amount of water you’re using.
  • The best tip is you can use an internal water pump for your tankless unit to boost the water pressure to your unit to work properly.

02. Gas Supply Issue

Girard tankless water heater needs sufficient fuel supply to ensure optimal performance for your RV water heater. Thus when there is an interruption in the gas supply, the burner won’t get enough gas for ignition and ultimately you will not get hot water as you demand. 

Either you have an empty LP tank and the gas supply to your water heater is being cut off. Despite this, several more factors would be responsible here. Like:

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

How To Fix:

First off check the fuel tank and make sure there is sufficient gas for ignition. Next, check the gas shut-off valve to see whether it is turned on all the way and there should not be any obstructions. 

Then, inspect the gas supply line for any blockage. Clean out all the stuck debris in the LP plumbing system to allow fluent gas flow in the system. While doing so, if you find any bent gas hose, don’t miss to straighten that. 

Finally, remove the front cover of your unit to access the gas valve assembly from the inside. 

You need to ensure the gas valves are in perfect working order. It’s better if you measure the output gas pressure from the gas valve connection. It should give a reading of 1.5” WC on low heat and 7.8” WC on high heat. If not, adjust the gas valve or you may need to replace it. 

03. Malfunction In The Plumbing System

Most of the time, the hot water in your tankless water heater is related to the shower plumbing system of the user. It may be related to the anti-scald valve in the shower faucet assembly. 

The thermostatic anti-scald valve is a safety device in the shower handle that is used to mix hot and cold water to deliver shower water at a comfortable temperature. 

thermostatic anti-scald valve of girard tankless rv water heater

The best chance is you are using an anti-scald device on the shower handle and it is not adjusted properly which is causing a sudden drop in the water pressure and temperature. 

Despite the malfunctioning mixing valve, you may have a bad faucet cartridge as well that is not allowing water to get as hot as you demand.

So, now we’ll inspect the shower handle and adjust the mixing valve:

How To Adjust Shower Mixing Valves?

Here is the basic process that will give you ideas on how to adjust the temperature on a mixing valve:

Step 1: First up, remove the hot water shower handle. For instance, you will find a screw on the handle side. 

shower mixing valve of girard tankless rv water heater

Step 2: Take an Allen wrench or screwdriver and remove the screws to expose the hot water valve stem.

Step 3: When done, remove the knob from the stem. There may be an O-ring, take it off to adjust the center part.

Step 4: Now pull the valve stem slightly out and turn it counterclockwise or to the hotter side. Put the knob and O-ring back onto the stem.

adjusting the temperature on a mixing valve of girard tankless rv water heater

Step 5: Finally reinstall the shower handle and secure it with the screw firmly. Press the cap back into its place.

After adjusting the mixing valve, you can expect hot water from your shower as you need. If not, you may have a bad cartridge that needs replacement. Contact a professional plumber to deal with the issue.

04. Degradation In Power Supply

Along with the fuel supply issue, chances are your tankless water heater is going through a degradation in power supply that is affecting the heating function. A Girard tankless water heater needs a properly grounded 12VDC electric power system for proper operation of the heater. 

In case there is an interruption in the power supply, the system fails to light even after several attempts and ultimately you won’t get hot water.

Well! Now let’s track down what are the responsive factors that lead to power supply issues in your water heater:

  • Loose wiring connection
  • Faulty heater ON/Off switch
  • Blown fuse
  • Insufficient voltage supply

How To Fix:

As for the first step, ensure that you have connected your heater to a properly grounded 12V DC electric power system. If needed, test the voltage of the power system with a multimeter. 

Now remove the front panel of your heater and you will find the heater power switch just at the front. 

Make sure it is in the ON position and in perfect working order. Just below the ON/OFF switch, you will have a fuse for your tankless unit. Replace the fuse if it is blown.

When done, verify all the wiring connections going through your water heater. Tighten the loose wiring and replace the worn-out ones. If you are technically inclined, I earnestly recommend contacting a certified electrician to deal with your electrical supply issue.

05. Ignition Failure

If still, your tankless water is not providing hot water properly, higher chances are the unit is not igniting properly. When there is no flame due to failed ignition, certainly you won’t get hot water from your heater as it should. 

Due to that, you may encounter Girard tankless water heater error code e1 on the remote display. 

So while concerning other factors, you shouldn’t miss this major factor as well to fix your hot water issue. 

I bet the problem is occurring from the clogged burner orifice. If the orifice is blocked by debris and shoots, it will prevent the burner from firing.

Apart from the burner issue, the faulty igniter is another major reason for ignition failure in your RV tankless water heater. 

There would be faulty igniter wiring connections to the control board or the igniter assembly would be obstructed with debris. Or, the defective or cracked igniter is the culprit itself. 

How To Fix:

Let’s go through the below processes to fix the ignition issue:

Step 1: Check The Burner Orifice For Any Blockages

First up, inspect the burner assembly for cleaning. You will find up to 6 orifices that are metering gas into the burner. To access the main burner, disconnect the mounting screws from the output gas line and the burner case. This will let you access the orifice tabs.

Now take a strong vacuum cleaner and clean out the scale deposits from the burner assembly. If needed, you can use a wire brush here as well. 

Step 2: Verify The Igniter Wiring Connection

Along with the burner, you have to verify the igniter condition as well. For instance, inspect the igniter wiring connection to the control board. Make sure the connections are stable and secure enough.

When done, visually check the igniter for obstructions. Take 100-grit sandpaper and clean out the carbon or a white substance build-up on the igniter. If needed, replace the bad igniter with the help of a professional. 

06. Bypass Valves Are Set Incorrectly 

If all the troubleshooting steps fail to resolve the Girard tankless water heater no hot water issue, the higher chance is you have the bypass valve that is causing the plumbing issues. 

The purpose of the bypass valve is mainly to prevent antifreeze from going into the RV heater during freezing conditions. But generally, winterization by-pass kits are not required in tankless water heater systems. In case you are using it, I bet it is wrongly set which affects the overall function of the heater.

How To Fix:

First off, inspect the bypass valves to ensure that they are fully set in their Summer positions. Or, it’ll be better if you close both the hot and cold bypass and open the water supply valves all the way up.

07. Overloading Of The System

Last but not least, when you are fixing the hot water issue, you need to verify whether your tankless water heater system is overloaded. It is the common phenomenon that the users most often encounter. 

It mainly happens when you are using too many hot water fixtures at the same time which is overfilling your tankless unit’s potential. 

Basically, all tankless water heaters have a flow rate capacity that gives an idea of how much hot water can be used simultaneously. But in case your Girard tankless water heater becomes overloaded, it will fail to continue the heating process and immediately trip the circuit breaker. Ultimately your heater turns off.

How To Fix:

When you encounter a system overloaded issue on your tankless water heater, minimize the hot water demand by turning off the extra hot water fixtures. Then, reset your Girard tankless water heater to get it back into normal operation. 

To overcome this issue in the future, install two or more tankless water heaters that are connected in parallel to fulfill your hot water demand simultaneously. Or, update your tankless water heater to a higher-capacity one.


What to do when I have no operation at the UCP on my Girard tankless water heater?

First, confirm the good power and ground to electrical connection to your water heater. Check for voltage at the wiring connection of the UCP. It should be 9 to 11VDC. If needed, replace the bad UCP or control board.

What to do when there is no water flow in my Girard tankless water heater?

When there is no water flow at all, verify the water shut-off valves and open them all the way. Also, inspect the water flow sensor and ensure it is not clogged and is in well-working condition. If needed, replace it.

In Closing!

As an RVer, nothing will be more frustrating than when your tankless water heater doesn’t work properly. It’s even more upsetting when your  Girard tankless RV water heater is not getting hot enough or as you expect. 

First things first, ensure that you have adjusted the water heater to the right temperature to fix the issue. Plus, the water pressure going through your heater should be at the recommended level. Otherwise, the burner won’t ignite, and you’ll run out of hot water constantly.

But overall, to overcome the issue, you need to always concentrate on the proper maintenance of your heater. If you are wondering how to do so, our comprehensive guide on Girard tankless water heater maintenance will be enough to guide you to the right path. Have a look at the guide and ensure optimal performance from your Girard tankless model!

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