Tankless Water Heater Issues

[TravelingMerrs]

First post here...

First time out in our new to us 2022 351 last weekend and couldn't get the Suburban tankless water heater to ignite.

Propane supply is good (ran furnace & stove top), had plenty of water flow (tried opening multiple faucets at once and removed water pressure regulator from the hose), confirmed fuses were good and nothing was tripped at the panel, and confirmed there were no error codes on the digital display.

When hot water was 'called' I could hear the units fan turn on and it attempt to ignite (ticking sound) but then would shut itself off after a minute or so.

Any thoughts or ideas on what else to check for?

 

[Mikendebbie]

Welcome to the forum!

There has been several threads on the Suburban IW60 for you to look thru for troubleshooting. Best way to find them is use the google search in the brown box above, and search "Suburban IW60"...the threads will show up.

We have a IW60 in our unit. When we set up, I light and run the stove burners for a few moments to make sure the gas is flowing, then I turn on the kitchen sink faucet...whirring starts and then the flame comes on. Calling Airxcel Suburban will not help you...their standard answer is go to a dealer for help. Hopefully we can help you troubleshoot here in the forum.

 

[TravelingMerrs]

Welcome to the forum!

There has been several threads on the Suburban IW60 for you to look thru for troubleshooting. Best way to find them is use the google search in the brown box above, and search "Suburban IW60"...the threads will show up.

We have a IW60 in our unit. When we set up, I light and run the stove burners for a few moments to make sure the gas is flowing, then I turn on the kitchen sink faucet...whirring starts and then the flame comes on. Calling Airxcel Suburban will not help you...their standard answer is go to a dealer for help. Hopefully we can help you troubleshoot here in the forum.

Thanks! That's funny, I called Airxcel this AM and while friendly, they told me to work with a dealer.

I did a search on the site before posting and didn't see this same issue, but I'll keep searching though.

Good to know about running the stove at the same time. I did them separate of each other, so next time I get it out I'll give this a try.

 

[Bourbon County]

If I recall, previous issues with the Suburban tankless involved lack of combustion air and fuel pressure. If yours goes to the point you can hear the ignitor clicking, you are getting air flow and the pressure switch is closing. I would look at the gas solenoid valve or it's possible the controller is not sending signal to the solenoid to open. That's a 2 stage burner and it should initially light on high fire and throttle down for a low water flow.

Turning the stove on to check gas pressure/flow is a test, but not necessarily the best test here. The stove is a very simple burner while the water heater is an induced draft type burner. It uses a blower to supply combustion air and exhaust the fumes, it's much more sensitive to gas pressure than the stove. I would not rule out a gas pressure issue. This is in no way a test, but an indication: can you smell gas while the burner is trying to fire? When the blower starts at beginning of cycle, part of it's job is to exhaust any residual gas remaining in the burner. You might be able to smell gas then and again once you start hearing the clicking. The only true test is to check pressure with a manometer.

 

[Viper02]

Link to service manual for the IW60 :
https://www.rvupgradestore.com/v/vspfiles/assets/pdf/IW60-Manual.pdf

One thing you might try is removing 12 vdc power that runs to the WH circuit board... This is the same as opening up the unit and pressing the reset switch on the circuit board ( but much quicker and easier )

Agree the pressure switch is closing properly else the ignitor would not fire... Both the ignitor firing and the solenoids opening on the LP valve on the WH occur at same time

If removing 12 vdc and reapplying and trying still hasnt corrected the issue I would open the unit panels up..

Then using a multimenter test for 12 vdc signal at the LP solenoid while a helper turns on a hot water faucet

 

[Viper02]

IW60 schematic and I have marked with a red square where to measure for 12 VDC to the LP solenoid when you hear the ignitor firing

Also added small PDF on how to test the air pressure switch .. might be useful down the road

 

[TravelingMerrs]

If I recall, previous issues with the Suburban tankless involved lack of combustion air and fuel pressure. If yours goes to the point you can hear the ignitor clicking, you are getting air flow and the pressure switch is closing. I would look at the gas solenoid valve or it's possible the controller is not sending signal to the solenoid to open. That's a 2 stage burner and it should initially light on high fire and throttle down for a low water flow.

Turning the stove on to check gas pressure/flow is a test, but not necessarily the best test here. The stove is a very simple burner while the water heater is an induced draft type burner. It uses a blower to supply combustion air and exhaust the fumes, it's much more sensitive to gas pressure than the stove. I would not rule out a gas pressure issue. This is in no way a test, but an indication: can you smell gas while the burner is trying to fire? When the blower starts at beginning of cycle, part of it's job is to exhaust any residual gas remaining in the burner. You might be able to smell gas then and again once you start hearing the clicking. The only true test is to check pressure with a manometer.

Link to service manual for the IW60 :
https://www.rvupgradestore.com/v/vspfiles/assets/pdf/IW60-Manual.pdf

One thing you might try is removing 12 vdc power that runs to the WH circuit board... This is the same as opening up the unit and pressing the reset switch on the circuit board ( but much quicker and easier )

Agree the pressure switch is closing properly else the ignitor would not fire... Both the ignitor firing and the solenoids opening on the LP valve on the WH occur at same time

If removing 12 vdc and reapplying and trying still hasnt corrected the issue I would open the unit panels up..

Then using a multimenter test for 12 vdc signal at the LP solenoid while a helper turns on a hot water faucet

Thank you both for the information. I will give the 'smell test' a try and removing the 12v power. I'm not real comfortable with some of the other tests, I think they're beyond my abilities, but I do appreciate the suggestions.

I've got an appointment scheduled for the end of next week in case I can't fix it in the meantime

 

[JABURKHOLDER]

This may sound dumb, but, are you opening only a hot water faucet ? Do not turn on cold water.
Also, don’t open multiple faucets at once, only the one where you need hot water.

 

[TravelingMerrs]

Wanted to give an update here.

The local service center pulled the water heater and it worked fine outside of the rig. They checked the propane regulator and all was good there as well. They said that it was a clogged propane line going to the water heater that was the issue. There was oil build up in the line clogging it. They cleaned it out and reinstalled and all is good now. Seems odd to me, but what do I know A quick Google search shows that it is a 'thing' that can happen.