Water heater

Mikey P · 05-08-2021, 09:54 AM

2 full tanks, Gas on,(gas stove lights and works) Pilot lit, knob turned to on, temp selector on hot. Burner will not ignite, EXCEPT the burner pops a bit and ignites a small flame right at the orifice. Dismantled the burner and the orifice is clear and open, what do we focus on from here?

**chuckster57** · 05-08-2021, 10:04 AM

What did you do to clean the orifice?

If you didnt do anything, then use compressed air and blow it out BACKWARDS after you take it off.

Mikey P · 05-08-2021, 10:18 AM

removed from heater and used compressed air forward and backwards

**chuckster57** · 05-08-2021, 11:45 AM

Quote:

Originally Posted by Mikey P

removed from heater and used compressed air forward and backwards

Ok, If you did remove just the orifice from the burner tube, then the next step is to check gas pressure. You need a Manometer for accurate measure as LP operates at about 1.5 PSI.

TURN ALL GAS APPLIANCES OFF, then turn off the LP tanks. Loosen the gas fitting at the water heater, turn the PL cylinder back on and check for a decent flow of gas. You should be able to smell it real good and you should have to use a slight amount of pressure to plug the end with your finger.

If you have a decent flow then the issue is in the orifice or control valve assembly. PUT IT BACK TOGETHER WITH THE LP TURNED OFF. once finished used soapy water on any connection you took apart.

NH_Bulldog · 05-08-2021, 01:00 PM

Pilot light indicates an older model? Could be thermocouple or gas controller

**chuckster57** · 05-08-2021, 01:21 PM

Quote:

Originally Posted by NH_Bulldog

Pilot light indicates an older model? Could be thermocouple or gas controller

I agree older model, thermocoupler would still allow it to light, but it would go out when you let off the button that bypasses it.

Mikey P · 05-10-2021, 01:20 AM

Yes in a Keystone Columbia 2002. I understand the gas flow and since then pilot is getting gas and the fact that the burner pops and a small flame erupts at the orifice, I am assuming at this point gas is getting through the valve somewhat BUT I am concerned that the thermocoupler is malfunctioning which is the cheapest investment at 30$ for a new coupler and pilot tube and a burner tube with orifice. I will try that. The valve is 180 so not going there just yet. Thanks for the input guys and I will post my resolutiion.

**JRTJH** · 05-10-2021, 07:43 AM

Quote:

Originally Posted by Mikey P

Yes in a Keystone Columbia 2002. I understand the gas flow and since then pilot is getting gas and the fact that the burner pops and a small flame erupts at the orifice, I am assuming at this point gas is getting through the valve somewhat BUT I am concerned that the thermocoupler is malfunctioning which is the cheapest investment at 30$ for a new coupler and pilot tube and a burner tube with orifice. I will try that. The valve is 180 so not going there just yet. Thanks for the input guys and I will post my resolutiion.

I'd guess that you have a Suburban (Dometic) standing pilot water heater ???

If so, it has a porcelain lined steel tank. It's current 18-20 years old. I'd guess that there is likely to be some serious corrosion in the tank. Spending $180 for a gas valve assembly and then "flexing the tank face to install it" may be the "kiss of death" for the tank seams.... A new tank will run about $250. That means you'd have around $430 invested in an "old water heater with a new tank and a new control valve" but the rest is still 18+ years old... A new "standing pilot water heater" runs somewhere from $375-475, depending on the size.

Before "throwing new parts looking for a fix" I'd consider the "final result"...

In your first post you state, "Pilot lit, knob turned to on, temp selector on hot. Burner will not ignite,..." If the pilot lit and remains lit when you release the red button, the thermocouple is working. Its purpose is to turn off gas if the pilot blows out (heat loss) As long as the pilot is heating the thermocouple and the pilot remains lit, it's not the thermocouple.

ADDED: Have you used a "duct brush" to clean the heat tube that circles through the water tank? If not, you may have some spider webs, rust or carbon/soot buildup in that 2" tube. If there's any "heat flow obstruction" you can get a backpressure that will "deflect the pilot flame away from the thermocouple when the main burner is operating. That will cool the thermocouple and then the safety valve will kick in to turn off gas to the pilot and the main burner.

Also, have you disconnected the gas line "TO the gas valve" and used compressed air on the "supply side of the gas line"? A WAG, but you could have something that "flaked off the black iron pipe" and is partially blocking the gas going into the gas valve from the regulator.

Devin_Noel · 05-12-2021, 08:54 AM

Quote:

Originally Posted by JRTJH

I'd guess that you have a Suburban (Dometic) standing pilot water heater ???

If so, it has a porcelain lined steel tank. It's current 18-20 years old. I'd guess that there is likely to be some serious corrosion in the tank. Spending $180 for a gas valve assembly and then "flexing the tank face to install it" may be the "kiss of death" for the tank seams.... A new tank will run about $250. That means you'd have around $430 invested in an "old water heater with a new tank and a new control valve" but the rest is still 18+ years old... A new "standing pilot water heater" runs somewhere from $375-475, depending on the size.

Before "throwing new parts looking for a fix" I'd consider the "final result"...

In your first post you state, "Pilot lit, knob turned to on, temp selector on hot. Burner will not ignite,..." If the pilot lit and remains lit when you release the red button, the thermocouple is working. Its purpose is to turn off gas if the pilot blows out (heat loss) As long as the pilot is heating the thermocouple and the pilot remains lit, it's not the thermocouple.

ADDED: Have you used a "duct brush" to clean the heat tube that circles through the water tank? If not, you may have some spider webs, rust or carbon/soot buildup in that 2" tube. If there's any "heat flow obstruction" you can get a backpressure that will "deflect the pilot flame away from the thermocouple when the main burner is operating. That will cool the thermocouple and then the safety valve will kick in to turn off gas to the pilot and the main burner.

Also, have you disconnected the gas line "TO the gas valve" and used compressed air on the "supply side of the gas line"? A WAG, but you could have something that "flaked off the black iron pipe" and is partially blocking the gas going into the gas valve from the regulator.

I'll 2nd this. The whole unit isn't that expensive, especially compared to a pile of parts for an old unit that may be on it's last legs already. Not that hard to install. A new unit will be electric ignition. An extra $50 or so gets you one that runs on gas and/or 120v (will run on either, or both, or much faster heating on shore or gen power).

Mikey P · 05-12-2021, 02:23 PM

Okay,,,,,relit the pilot. turned the knob to On then turned the temp adjust to high. Then I used a large open end wrench and tapped the valve box in several places and the burner came on. I will try the heater off and on the correct way until I head off to a campground in June tom make sure it is dependable. Thanks all for the guidance.

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