Big Maxx problems

[gogolf0401]

Hey guys, so I recently hooked up my new Mr. Heater Big Maxx garage heater and it is not working right. It doesn't hold a flame consistently, pulsates weird and has trouble stabilizing.

It came set up for NG, so I converted it to LP using the provided kit. Installed the LP orifices (smaller hole) and the new spring and screw for the correct pressure. I set the screw at the recommended turns. I don't have a pressure gauge to check the pressure. When it is running I tried adjusting the screw and it doesn't appear to have an impact which is strange.

watch the video and at 2:50 it seems to stabilize, but it pulsates weird..
Notice that it stabilizes only once the igniter stops, so not sure how to read that. Maybe too much gas and re-ignition causes the burners to go in and out?

See this link for a video
https://photos.app.goo.gl/3XVjne71W9hT7TpH7

Notice the diagnostic LED is flashing at the fast rate, which indicates normal operation.

Faulty gas valve?

Do I need to add anther gas regulator just for this heater?

 

[acmikee]

you need to check the gas pressure this is something that you can just wing it and hope that is correct

 

[The Cobbler]

it looks l to me like a gas flow/pressure issue
what are you using for a regulator off the propane tank?

 

[ljhhontx]

Seems like it has air in line, did you purge air out of new line? Pressure does seem high but I work natural gas and am not used to propane.You can buy a water manometer or make one out of clear tubing looped and attached to board with a foot of water in it, make a loop for the water to pool in and measure distance between ends of water column in vertical
, not sure what press in inches of water column should be but should show on heater, hook it to manifold, should have a plug to put hose barb in.

 

[gogolf0401]

it looks l to me like a gas flow/pressure issue
what are you using for a regulator off the propane tank?

I think a 4lb regulator for the whole house

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[gogolf0401]

Seems like it has air in line, did you purge air out of new line? Pressure does seem high but I work natural gas and am not used to propane.You can buy a water manometer or make one out of clear tubing looped and attached to board with a foot of water in it, make a loop for the water to pool in and measure distance between ends of water column in vertical
, not sure what press in inches of water column should be but should show on heater, hook it to manifold, should have a plug to put hose barb in.

I forgot to purge, but it has run long enough to get rid of the air. Thanks for the tip on the gauge.

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[The Cobbler]

I think a 4lb regulator for the whole house

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that may be your problem,I think you need a secondary regulator to take it to about 11" of water column( less than 1/2 psi)

 

[gogolf0401]

that may be your problem,I think you need a secondary regulator to take it to about 11" of water column( less than 1/2 psi)

Ok thanks. I'll look into adding a secondary.

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[TractorJeff]

Yes, the feed into a Big Maxx is 11 inches of water.
If you are relying on the 4psi regulator, then you are over pressuring the small internal regulator(that you put the spring and screw) causing the pulsation of the flame

 

[gogolf0401]

Just following up here... I added a second regulator after I borrowed a manometer and realized the inlet pressure was 56 in/H2O.. supposed to be 11-14 in. After adding the regulator I was able to adjust both the regulator and gas manifold to get the appropriate pressures and the heater works like a charm now. Thanks for the help guys!

 

[The Cobbler]

great news. . good thing you didn't screw up the gas valve by over pressuring it.