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Morco water heater eco 11 litre have replaced thermocoupling 2 months ago,now gas burner cutting off whilst showering or wont stay lit sometimes

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SOURCE: Furnace runs about 1 minute, then total shutdown

What type of gas supply line do you have? Is it black pipe or copper? If it is copper, there can be a film like substance that builds up on the inside of the copper. The debris will the get caught in a pre screen where the supply enters the valve thus cutting the supply of gas to the unit. Also, the thermocouple may be bad. You didn't say that you replaced it. Try replacing it as well. Also, you could have a limit switch turning the system off and thus cutting the gas off completely but it is highly unusual for the pilot to be cut off as well unless the pilot is being blown out when the gas is shut off. Also, turn the unit to fan only without calling for heat. Using a flame of some sort, put it into each baffle of the heat exchanger. If your flame is being blown around in one of the baffles, then you have a hole in the heat exchanger and what is happening is that the roll out switch is cutting the unit off and the air still moving through the heat exchanger is blowing the pilot out. I have seen this actually happen. If your furnace is in excess of 15 years old, it does need to be checked for possible holes. If it is in excess of 25 years old, it is a huge possibility that the unit has already developed a hole. If you feel hair coming out of one of the baffles, then shut the unit down immediately and have it replaced!

Posted on Apr 05, 2009

  • 68 Answers

SOURCE: water heater pilot wont stay lit

try cleaning the top of the pilot light jet if you can get to with small brush then blow it clean with a compressor.

Posted on Aug 30, 2009

  • 13 Answers

SOURCE: gsw heater pilot stays lit, but when the main

It sounds like your main valve. The diaphram may be loose fitting or it has a small leak.

Posted on Oct 03, 2009

Testimonial: "Thanks for replying so quickly"

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SOURCE: i have a richmond gas hot water heater model

resetting your lock out for richmond power vent

Posted on Nov 26, 2009

john224
  • 1378 Answers

SOURCE: Natural gas hot water heater not stying lit

Probably a bad solenoid in the gas valve. Higher voltage of a new thermocouple keeps it open longer but it still fails over a period of time. Look into a new gas valve for the water heater.

Posted on Dec 17, 2009

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Reliant 501 Natural Gas won't stay lit


Reliance water heater?
Thermocouple is good if the pilot stays lit continuously.

501 is older model. Unknown if this unit has FVIR protection and sealed combustion chamber or open air intake on front of unit.
http://waterheatertimer.org/pdf/Reliance-2006-Service-Handbook.pdf

With FVIR protection:
Get more fresh air to the unit.
Clean the flame arrestor screen.
Test and replace the thermocouple:
http://waterheatertimer.org/How-to-test-water-heater-thermocouple.html
Inspect and clean burner and combustion parts
Test gas pressure, bleed air out of gas line.
Replace gas control valve.
Test draft air by lighting match and see if smoke is pulled into the vent pipe at draft hood on top of tank.

Aug 20, 2012 | Water Heaters

1 Answer

After hot water demand, burner stays lit, blew up Pex supply line


Thermocouple has 2 ends. One end attaches to gas control valve, other end sits inside the pilot flame.
Flame heats thermocouple, causing tiny electrical current that is detected inside the gas control valve and keeps the gas valve open so water heater can turn on when thermostat calls for heating.
If pilot goes out, then no electric current reaches gas control, and all gas to burner and pilot is shut off.

If pex line burst, that implies very high pressure, caused by closed system with check valve that stops expansion, or possible clog in the water line, or high local water pressure, or clogged factory-installed heat traps.
Put pressure gauge like BTG100 on the drain valve to check pressure, should not exceed 80psi, install pressure reducing valve on cold water line, install expansion tank on cold water line. Remove heat traps and install ordinary pex-lined di-electric nipples from hardware store.

If the water was super hot, then overheating could have caused the pipe explosion.
However the gas control thermostat is ECO protected, and if ECO (energy cut off) trips because of high heat detected inside the tank or combustion chamber, the gas control will trip off and no longer work, gas control needs to be replaced. Some newer electronic gas controls can be reset, but that type heater uses a thermopile instead of thermocouple.
Thermopile is basically a group of thermocouples, that product more electric current that is used to power electronics inside the gas control valve, which issues an error code on the gas control, and some day will send a text message each time out-of-range event occurs.

Copy following links for troubleshoot resources, including troubleshoot by type of gas control valve:
http://weaterheatertimer.org/How-to-troubleshoot-gas-water-heater.html
http://waterheatertimer.org/Low-hot-water-pressure.html
http://waterheatertimer.org/pdf/How-to-replace-water-heater-gas-valve.pdf

Jul 12, 2012 | Bosch Aquastar 125B Gas Valve NG - Part...

1 Answer

The pilot won't stay lit on gas hot water tank.


Make sure thermocouple tip is seated inside the burner flame.
Make sure thermocouple is not overtightened. Finger-tight + 1/4 turn.
If the pilot lights, then ECO energy cut off is not tripped, but gas control valve might be bad.
Check color of pilot flame: it should be strong and clear blue.
If pilot flame is weak, or color of flame is yellow-orange: Clean pilot orifice and burner and combustion parts on yearly basis.
Clean air intake screen if applicable.
Increase air supply to water heater. Open a window and see what happens.
Check for adequate draft going up chimney using match under vent hood to see if smoke drafts immediately upwards.
Bleed air out of gas line.
Check gas pressure.

Open following links for troubleshoot resources:
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf
http://waterheatertimer.org/pdf/Pilot-outage-troubleshooting.pdf
http://waterheatertimer.org/pdf/Vent-spillage-test-atmospheric-gas-water-heater.pdf
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot

Sep 21, 2011 | Water Heaters

1 Answer

Hi i have a atwood 22.7 litre water heater model mpd93754 . IT ignites heats water, but wont shut off when it gets too hot. could you please help solve this problem . many thanks rod baker.


Gas control valve thermostat might be bad.
The copper cylinder located on back of gas control that sticks into water is the thermostat.
If thermostat is not reading correct temperature, then gas might stay lit.
Usually the gas control will sense overheated water and trip the ECO so no gas will flow to burner.
In any case, the gas control valve is replaced.
http://www.adventurerv.net/images/91601.jpg

Open following links to see typical manuals, service manual, parts link, and other resources:
http://waterheatertimer.org/Atwood-water-heater-resources.html

Jul 28, 2011 | RTO Atwood Water Heater - 6 Gal LP

1 Answer

Pilot wont stay lit on waterheater. I replaced Thermocouple and that did not fix it. It will stay lit on vacation setting.


Most gas water heater problems can be fixed with yearly service that cleans burner and burner parts, checks gas pressure and bleeds air out of gas line, cleans air intake, and checks for venting and air intake problems.
Open following links for resources:
http://waterheatertimer.org/pdf/Pilot-light-will-not-stay-lit.pdf
http://waterheatertimer.org/pdf/Attic-Ventilation-and-Pilot-Outage-in-Gas%20Water-Heaters.pdf
http://waterheatertimer.org/How-to-install-gas-water-heater.html#troubleshoot

Jul 27, 2011 | Water Heaters

4 Answers

Whirlpool gas hot water heater thermocouple is bad


HELLO.. "ALL' THE WHIRLPOOL GAS WATER HEATERS SOLD BY LOWES ARE JUNK...THEY HAVE A DESIGN FLAW...THAT KEEPS THE PILOT LIGHT FROM STAYING LIT...MANY LAWSUITS TO BOTH LOWES & WHIRLPOOL...THIS HAS BEEN GOING ON SINCE 2000 ....TO SAVE YOU THE MOST AGGRAVATION & TIME...REPLACE THE HEATER WITH A "DIFFERENT" BRAND..ANY REPAIRS WILL FAIL AGAIN ...WHIRLPOOL & LOWES ARE "NOT" SATNDING BEHIND THESE ....YOU WOULD THINK IN 9 YEAERS...WHIRLPOOL COULD RE-DESIGN THESE TO MAKE THEM RELIABLE....BUT...THEY HAVE BOTH CHOSEN TO DO "NOTHING".......

Jul 15, 2009 | Heating & Cooling

1 Answer

The pilot light on my gas water heater continually goes out. I can re-light the pilot and get it going. The gas burners goes on runs for awhile. I'm assuming when that when the temp hits the desired temp...


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The pilot assembly should look similar to the pic above. Depending on where you live, you may be required to hire a certified plumber to replace the parts. If not you can do it your self. Keep in mind if it's not staying lit you also need to check the thermostat and the thermocoupler before replacing the pilot assembly. There is a good chance it is just the thermocoupler going out. It is one of the first things to check when troubleshooting a pilot light problem with a gas water heater. A thermocouple determines if the pilot light is lit. If it's not lit, the gas valve fails. If that's the problem, replace the thermocouple.


  1. Shut off the gas valve on the water heater and the gas valve on the line near the heater. Remove outer and inner doors, and loosen the pilot and supply tubes and the thermocouple connections to remove the burner assembly.
  2. Step 2 Loosen the screw holding the thermocouple to the bracket. Remove old thermocouple. Bring it with you to the store to ensure you are buying the proper replacement.
  3. Step 3 Install the new thermocouple. Position the thermocouple so that the pilot flame heats 1/2 inch of the tip.
  4. Step 4 Reinstall burner assembly in the water heater. Tighten burner supply tube, pilot tube and thermocouple connections. Tighten thermocouple no more than a quarter turn more than hand-tight.
  5. Step 5 Turn on both gas valves. Check supply tube and pilot tube for leaks with soapy water. If soap bubbles, tighten connections to fix leak. Ignite the pilot light, and make sure the thermocouple tip is heating up. Replace inner and outer doors.

Jul 09, 2009 | Northern Tool Water Heaters

2 Answers

I have replaced the control valve and thermocouple but burner wont stay lit. when burner shuts off so does the pilot


Thermocouple is probably not adjusted in to the pilot flame correctly, readjust and try again, if that does not work replace the thermocouple, not all brand new thermocouples are good right out of the bag

Jul 01, 2009 | Rheem 50 Gallon FVR NATGAS Water Heater...

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