Question about Mr. Heater MHU45LP

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Repeated ignition MHU 75 Unit starts, heats for period of time then shuts down and restarts, does this several times. After awhile unit may run and shut down normal. Replaced thermostat and blew out inside of unit with low pressure air. Did not stop the problem.

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-if the fuel is liquid (i.e. heating oil) there will be a filter which is likely the cause of the lack of fuel delivery....this is a $15 filter...available at many hardware stores..or even you fuel supplier
-the process is simple.

  1. ..TURN OFF THE FUEL (above/b4 filter)...
  2. spin off the filter...replace with the new one
  3. open the valve...bleed the system (don't screw the housing tight...let the fuel push the air out...ie. wait until the fuel spurts out the filter screws (this can be sorta messy)
  4. tighten filter...tada!
  5. if it works temporarily...then repeats the 'pop...goes out' then you still have air in the line
  6. if you followed the above steps 1-5...then we know it between filter and burner
  7. look at the bottom of the burner for the bleeder valve/screw...similar to car brake bleeder screw or a 1/2inch valve
  8. use a wrench...1/4 to loosen (have small bucket handy to collect fuel
  9. press & HOLD the red button to fire (note the fuel will now be pumped out the bleeder valve)
  10. wait a second or 2 for the 'stream' of fuel to be solid (ie. no bubbles in it)
  11. then tightten the valve the 1/4 turn...and release
  12. occassially you have to repeat this process a few times depending upon the length of fuel line
PLEASE BE CAREFUL....while the above is technically not difficult..you are dealing with a somewhat flamable liquid...(a bucket of fuel oil is actually difficult to light)...the 1st time is a steep learning curve...but after that you can do it in your sleep :)

if you are uncomfortable at all...then call a fuel burner technician...please!

Posted on Dec 21, 2008

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Hi and welcome to FixYa,

Initially, pls post back for any other fault indicator such as a blinking light.

Good luck and Thank you for using FixYa. Happy Holidays.

Posted on Dec 21, 2008

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Heating Mode (Goodman Service Manual)

· The furnace control checks for an open main limit (this
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1 Answer

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