Thor Omni/Magnitude Water Heater

[Zapnod]

I just bought the 2022 Thor Omni. The instant water heater worked great the first time we took out the RV. The second time I took it out the water heater gets to 90 degrees then cuts out.

Does anyone have any ideas?

[Scubawise]

Originally Posted by Zapnod

I just bought the 2022 Thor Omni. The instant hot water heater worked great the first time we took out the RV. The second time I took it out the hot water heater gets to 90 degrees then cuts out.

Does anyone have any ideas?

Did you try different settings on the control panel?
Does propane shut off or enough?

[Judge]

There are at least 3023 threads on this topic........... the search function is you friend. Here is just one of my replies to this topic over the past few years that should help:


Here are the primary issues causing hot water problem with the Girard Tankless Water Heater in order of most common occurrence.


1) 50% of the time the issue is related not enough water flow due to poor water pressure. You need at least 45PSI of water pressure coming into the coach. Many campgrounds have poor water pressure. You should be using a pressure regulator for incoming water to protect the coach from too much water pressure so look at the gauge and see what your water pressure is reading. See if you can adjust it for 45 - 50PSI if it is below that pressure. If you don't have a regulator or the campground isn't supplying at least 45PSI, try turning off the city water and using your fresh water tank instead and see if the hot water works properly.

2) 30% of the time the issue is people mixing cold water with the hot like they do at home and not setting the thermostat to the desired temperature and then only opening the hot valve for water. Do not open the cold water or use the water elsewhere in the coach when using the hot water. This causes the pressure to drop and the tankless will cut out if the flow drops too much.

3) 10% of the time the issue is related to construction debris in the water line cause the strainers (screens on the faucets and shower) to become blocked and restrict the flow. There is also a strainer / screen at the water inlet to the back of the unit. This can also become blocked with debris. Thor does recommend removing this strainer in cases where people are having flow issues. The house water system filter is before the tankless so assuming there is no construction debris in the water line coming into the tankless, the strainer should not be be needed.

4) 5% of the time the incoming water flow valve on the back of the Girard Tankless unit needs adjusted. When the incoming water temp is very cold, then slowing the flow will allow the water to spend more time in the heat exchanger to heat up enough.

5) 5% of the time it could be one of several other issues such as.... there is an actual problem with the tankless unit.... there is a bad faucet cartridge and it is allowing cold water to leak and mix in with the hot water.... there is a kink or some other blockage in the plumbing restricting flow.

[DavidEM]

I think Judge pretty well covered the bases. I experienced two of the problems he discusses:

On my new Axis, first the water line was kinked at the fresh water tank and the HW heater wouldn't work at all. Cleared that and it worked intermittently somewhat like yours but only at the shower. Other outlets worked fine.

Then I removed the flow restrictor at the base of the shower head which improved flow and all is well. I think that flow restrictor is more for use on shore water with higher pressure, but we always camp in parks without FHU sites.

David

[Bob Nodine]

This may seem obvious but make sure the propane is turned on and the tank has propane. If the stove works then the propane supply to the water heater should be ok.

[Zapnod]

Originally Posted by Judge

There are at least 3023 threads on this topic........... the search function is you friend. Here is just one of my replies to this topic over the past few years that should help:


Here are the primary issues causing hot water problem with the Girard Tankless Water Heater in order of most common occurrence.


1) 50% of the time the issue is related not enough water flow due to poor water pressure. You need at least 45PSI of water pressure coming into the coach. Many campgrounds have poor water pressure. You should be using a pressure regulator for incoming water to protect the coach from too much water pressure so look at the gauge and see what your water pressure is reading. See if you can adjust it for 45 - 50PSI if it is below that pressure. If you don't have a regulator or the campground isn't supplying at least 45PSI, try turning off the city water and using your fresh water tank instead and see if the hot water works properly.

2) 30% of the time the issue is people mixing cold water with the hot like they do at home and not setting the thermostat to the desired temperature and then only opening the hot valve for water. Do not open the cold water or use the water elsewhere in the coach when using the hot water. This causes the pressure to drop and the tankless will cut out if the flow drops too much.

3) 10% of the time the issue is related to construction debris in the water line cause the strainers (screens on the faucets and shower) to become blocked and restrict the flow. There is also a strainer / screen at the water inlet to the back of the unit. This can also become blocked with debris. Thor does recommend removing this strainer in cases where people are having flow issues. The house water system filter is before the tankless so assuming there is no construction debris in the water line coming into the tankless, the strainer should not be be needed.

4) 5% of the time the incoming water flow valve on the back of the Girard Tankless unit needs adjusted. When the incoming water temp is very cold, then slowing the flow will allow the water to spend more time in the heat exchanger to heat up enough.

5) 5% of the time it could be one of several other issues such as.... there is an actual problem with the tankless unit.... there is a bad faucet cartridge and it is allowing cold water to leak and mix in with the hot water.... there is a kink or some other blockage in the plumbing restricting flow.

I figured out there was not enough water pressure which is weird because I’m at a KOA. I had to take the regulator off to get enough water pressure.

[Judge]

Originally Posted by Zapnod

I figured out there was not enough water pressure which is weird because I’m at a KOA. I had to take the regulator off to get enough water pressure.

Glad its working….

You could have tried turning up the pressure on the regulator and that may have worked as well.

There is no standard for water pressure from one campground to the next…. even from one KOA to the next.

I have been at KOA’s where the pressure is great and others where the pressure is crappy. I was at a private campground last year where they warned you to use a regulator because the pressure was over 75PSI and could cause issues in some coaches with poor plumbing. They even sold them for people who didn’t have a regulator.

As I said….. most of the time it is a flow issue related to inadequate pressure.

[Zapnod]

Originally Posted by Judge

Glad its working….

You could have tried turning up the pressure on the regulator and that may have worked as well.

There is no standard for water pressure from one campground to the next…. even from one KOA to the next.

I have been at KOA’s where the pressure is great and others where the pressure is crappy. I was at a private campground last year where they warned you to use a regulator because the pressure was over 75PSI and could cause issues in some coaches with poor plumbing. They even sold them for people who didn’t have a regulator.

As I said….. most of the time it is a flow issue related to inadequate pressure.

I had a regulator that is a permanent 40-50 so I had to take it off. I will get a better regulator that is a adjustable. Thanks for all your help.

[OldWEB]

Originally Posted by Zapnod

I had a regulator that is a permanent 40-50 so I had to take it off. I will get a better regulator that is a adjustable. Thanks for all your help.

Now I am curious if your in house water pump would deliver enough pressure for the water heater, they are typically 40-50 psi.

[Judge]

Originally Posted by OldWEB

Now I am curious if your in house water pump would deliver enough pressure for the water heater, they are typically 40-50 psi.

A regulator adds some flow restriction. If the camp water was borderline, it could have easily caused his problem. That is why you should ahev a regulator with a guage. Just cause it is a 40-59 preset doesn’t mean that is whatbit divers if the pressure is less or just at 40.

The Girard sweet spot is 50psi but 45 minimum for consitent operation.

[EA37TS]

Originally Posted by OldWEB

Now I am curious if your in house water pump would deliver enough pressure for the water heater, they are typically 40-50 psi.

There are other factors involved. You could have 75psi of water pressure but not enough flow due to the flow rates of faucets, shower heads etc… Also mineral deposits that build up over time cut down flow. Our last sticks and bricks had a Rinnai tankless water heater and I had to change shower heads every year due to the waters high mineral content clogging the shower head and restricting flow.

[OldWEB]

Originally Posted by EA37TS

There are other factors involved. You could have 75psi of water pressure but not enough flow due to the flow rates of faucets, shower heads etc… Also mineral deposits that build up over time cut down flow. Our last sticks and bricks had a Rinnai tankless water heater and I had to change shower heads every year due to the waters high mineral content clogging the shower head and restricting flow.

Thank you to you and Judge, flow rate could be the issue.
But FYI we too have a Rinnai tankless (natural gas) in out S&B for the last 12 years, and it works flawlessly. I can have the tap run full bore or cut it down to a fast trickle and the heater delivers the same 120°F temp. Never had a low flow issue with it.

[Zapnod]

So I took out the filter attached to the water pump like Judge recommended. I also adjusted the water pump with a Alan wrench and the water works great now.

[Judge]

Originally Posted by Zapnod

So I took out the filter attached to the water pump like Judge recommended. I also adjusted the water pump with a Alan wrench and the water works great now.

The filter I was referring to is on back of the Girard Tankless Heater itself. I didn't recommend removing the strainer / filter from the water pump.

It is #21 in this screen shot of the parts schematic....

Adjusting your pump pressure may have helped or your pump strainer could have been partially clogged with debris. Part of annual maintenance should be cleaning the strainer.

[Lamokadave]

We've recently been getting an EO3 error code on the Gerard water heater. I haven't started to dive into this yet. Interestingly enough we still get hot water even with that code. Any advice for a quick fix would be appreciated..

[Judge]

Originally Posted by Lamokadave

We've recently been getting an EO3 error code on the Gerard water heater. I haven't started to dive into this yet. Interestingly enough we still get hot water even with that code. Any advice for a quick fix would be appreciated..

I’m not home but if I recall E03 means it is detecting the water is over 140 deg and it will shut down the system to protect from the water getting too hot.

There could be a sensor issue BUT if you are in an area where the water is very warm to begin with like Florida or Arizona that could cause it to get to hot quicker than notmal.

You could try two things…..

Try dropping the temp on the thermostat a few degrees.

That doesnt work make sure the flow valve on the back of the unit is wide open so the water only spends a minimal amount of time in the hear exchanger.