Mr. Heater Big Maxx Problem

[jgump]

Pinch it per the attachment. It works!

 

[prolawnsvc]

Well called the company and were very helpful. Left a msg and they called back within 15 min. said my board went bad shipped a new one. Hopefully this fixed my problem

 

[dropride]

I ended up just unbolting the upper roll out switch and laying it off to the side so it would stop tripping every 2 mins. I'll have to try pinching the burner shut when i get a chance.

 

[caper177]

Chalk up another flame rollout trip here too. It's time for Modine and similar manufacturers to fix this problem permanently, I've been reading forum posts that are dating back to 2006. I've been waiting for a repairman now for over a week and decided to look at my unit to see what the heck is going on. I see exactly what you mean by the flame coming out over the top of the highest burner tube. Mine is still under warranty so if the repairman doesn't soon get here I'll call around to see if another propane company is interested in the warranty work on mine. I can also notice a smell, not a propane smell as such but the smell of perhaps a dirty flame, although it appears to be a bright blue flame or a venting problem. This unit is only a year old btw.

 

[mikewease]

I had start problems from day one....kick off maybe a dozen times before it would finally stay fired up. I took the advice of another consumer and contacted the manu and they sent me a new board....installed it this morning and the furnace fired up immediately (first time in 2 yrs) has run to perfection ....all day..... With the new circuit board.

 

[looscrew]

Fix with pictures in PDF attached.

Just installed my new heater. Same problem, on reassembly, after your suggested fix, the top metering orifice fell out! No abuse!! Looks like it was bottomed out & was over torqued. That would explain the rollout switch shutdown. Glad the shutdown devices work. Not too happy at the moment no one to call on weekend. Thanks for the info. looscrew

 

[rickyjays]

I had the same prob turned the gas pressure down in the gas valvle and it quit kicking the roll switch out

 

[z28dad]

FWIW, I"m installing my heater that I purchased back in Jan-2011, and I went ahead and took out the top burner for a look and it was already fixed.

 

[jgump]

Mine's been working for a year now after the fix. No issues.....

 

[jkort77]

We just installed a heater last weekend and had the same problem with the rollout switch tripping. This is our fix and most likely everyone elses too. Take a look at the flame tubes and make sure that they are inserted into the holes by the burner. These tubes are only fastened in the rear of the heater and must have come out of the front holes during shipping. If the tubes are not inserted into the holes, the flame cannot be drawn into the flame tubes and the excess flame dances around inside the burner box causing the rollout switch to trip. They should have made these tubes with clips on them to stay in the holes.

 

[marty graves]

I installed my Big Maxx 45,000 unit and was working fine until yesterday. The external fan would shut off and the internal fan would continue running and it sounded like it was trying to ignite. If I turned up the thermosat it would light. I eventually unplugged it and then plugged it back in and the internal fan shut off. I turned up the thermostat today and nothing would work. The unit would not even turn on....The LED light is blinking three times so I know it has power.

 

[dave67fd]

3 Flashes= Pressure switch failed closed before CAB (cumbustion air blower) is energized
or failed open after CAB is energized.

Just a guess, Make sure your exhaust pipe isin't blocked or something causing it to hang-up.

 

[dbart]

Greetings;
I just installed the replacement gas valve Enerco sent for my malfunctioning Big Maxx 45K NG heater. Still doesn't light. never has.

Brand new, purchased 11/16/11.
Installed, wired up, vented in exactly the same configuration a previous Hamilton Garage Heater was installed.
Symptoms - Thermostat calls for heat, exhaust blower comes on, igniter starts its buzz, I hear gas valve solenoid click, flame never starts. It does this 3 times, then shuts down with the lockout code showing, never having sensed flame.
When I disconnect the gas to the unit, and open the inline valve, gas comes out of the pipe, so I know there is gas getting to the heater gas valve.

These are exactly the same symptoms I saw right out of the box, and now with the second gas valve.

What are the other possible things which would explain all these symptoms?
What if the electrical leads to the solenoid are backwards? Would it still make the click, just not open the valve?

I'll be back on the phone with tech services tomorrow.

Any thoughts?

Thanks,
dave

 

[porcupine73]

^ Not sure about the not lighting; are you sure the ignitor is working? Maybe one of those long grill lighters going when it starts the gas might show if it will light.

On my 75NG I too have the problem with the top limit switch. It was fine for about a year and then that started tripping out randomly. I ordered all new sensors and replaced them but it still did the same thing. So I ended up jumpering out the top limit switch. Else it just shuts of randomly then the fan just blows constantly.

 

[dave67fd]

If you remove the side access panel and shut the lights out you should be able to see the spark from the ignighters.
You should hear the solenoid click. Solenoids typically are non-polarized unless it has diode protection.
Although you have gas, have you checked line and manifold pressures?

Do not light it manually. It's not lighting because of a problem. Call a service guy if your not comfortable with it.

 

[Wells.M]

I googled the problem with my heater tripping the upper flame rollout sensor and this thread popped up. I then decided to perform jgump's pinching of the upper burner flange and it worked perfectly. Im glad these old threads dont get erased. And thus brings my first post to an end. Thanks to jgump and all.

 

[psecco]

Hello, I have a 45000 gas heater the blower fan came apart i hung a fan behind the heater until i get a replacement, but now i get the 4 flash light on, now the fans stay running but will not heat. i disconnected the thermostat and the fans still run.what do i do?

 

[postb8822]

I googled the problem with my heater tripping the upper flame rollout sensor and this thread popped up. I then decided to perform jgump's pinching of the upper burner flange and it worked perfectly. Im glad these old threads dont get erased. And thus brings my first post to an end. Thanks to jgump and all.

Me too, same problem, same fix. Thanks for posting this info.

Been below zero here for two weeks so the units been running quite a bit to keep my garage at 35F. No issues anymore.

 

[postb8822]

PSECCO,

Your temporary fan was probably not powerful enough to keep the heat exchanger from over heating. Inside the heater there are a couple of high limit thermal switches. There is one visible inside the heater side of the unit, between the heat exchanger tubes.

On the electronics side, you have to find the other end of this sensor, and in between the wires connected to it there is a tiny button. Push the button to reset. There are two more of these near the burners which have been tripping for most of us with the the flame roll out issue (too much flame leaking about in the burner box)

Yours I would bet is tripped in the main heater area due to the faulty fan, and ineffective temporary fan. I don't think hanging a temp fan behind the unit is a safe solution until you get your main fan fixed.

Did the blade just come off the motor shaft, tell us more about your fan issue? There should be a screw in the side of the hub that you can reattach and tighten to get the fan fixed if the blades just came loose.

 

[kellyjohn39]

Re: Mr. Heater Big Maxx Problem HELP PLEASE

Hello ,

I have a 50000 BTU NG Ceiling Big MAXX brand new unit and it was working and now it flashes 4green lights and I have tried everything. It is not blocked outside the pipes are not clogged, they said there is a reset button but it does not push in left of the circuit board and am at a loss. The thermostat works.....anything I am missing here? Walk me through another way to fix this?

Thanks!
John

 

[Highdefcowboy]

Well... Don't mind resurrecting an old dead thread once in a while.... Especially when the thread is SO helpful....
Thanks to all who posted...
Bought house last march (2015)
Po had built garage (like 5 yrs ago).
Finished garage with all kinds of big intentions.
And a BigMaxx mhu75ng heater hanging from the ceiling....
He made a Big Mistake with the ng gas line and inspector said
"No gas for you..."
He then never finished the install... Electrical done, vent chimney done heater hanging.... No gas.
I buy the house he says.... Here's how I would run the line.... (Which was good idea)... I got it done about four weeks ago, my son and I trenched house to garage (two feet deep 15 feet long). Call in contractor... Not too bad price... But... Took two weeks to gittrdun.... Bah! Then he's done, calls me says he's 'got a fire' (later after near heart attack I figure out he means the right kind in the furnace) and he's 'outta here'.
OK longer story shorter.... He was really out fast, cuz he didn't notice that the fire was out within 5 mins of leaving.... Same top Venturi tube needs pinching issue described.....SO.... THANKYOU SO MUCH to the previous posters that helped me fix my new five yr old heater!
Epilogue....
Flue Vent blower motor became a little noisy a day after running....
Big thank you to Enerco (Mr Heater) and Canadian IPS for sending a new blower motor... Arrived today (under warranty) (back dated to the date I bought my house) what a nice Christmas present!
Thanks Garage Journal for having images in 4 year old threads that don't disappear when you click the link!! (So many forums do) great forum...
Great help! MERRY CHRISTMAS TO ALL.... And God Bless us... Everyone (and thanks for garage heaters too!) .
Doc
Oh PS
The heater is a great unit.... Not perfect out of the box..... But very little is these days.....

 

[davidw221]

I purchased a Big Maxx, voltage regulator was bad and the springs for two of the louvers were missing, called customer service only sent one set of springs, and no voltage regulator, those folks at Mr. Heater need to monitor their employees closer to get better products out the door.

 

[myveryfastgt]

The fan will continue to run as long as it is still blinking that code. You need to reset the flame rollout switch.

Mine keeps tripping this after like 20 mins. Its new.. And my contractor will not call me back anymore and modine is no help.

How did you fix yours from popping?

 

[tolson]

Hello all, I am old,not too eager to freeze so I waited until now to try a fix.

Hello,I signed up to the site to glean some info on how to make my 75000 btu mr heater big max run again. I purchased several years ago and first hooked it up last fall. Ran well then shut off after reaching temp set on thermostat, the next start was brief then shut down. Turned off the gas, unplugged the power and off went the thermostat. Opened side panel then proceeded to turn on gas valve,plugged in power cord and flipped thermostat to heat. Panel was blinking normally then tried to start and shut down. Two blinks off two blinks and so on. I hope I explained this well enough to find a fix.

Thanks for any help offered.

 

[tolson]

jgump
we read your file and will try it to see if this will help our situation. Thanks for posting your fix.

 

[kent1]

Hi guys,
I joined today because of this topic. My heater, in addition to the occasional 4 flashes, also flashes 5 times meaning flame sensed with gas valve off. Any thoughts on what's causing that? If I flip the breaker it resets and works for awhile.

It looks like there is a lot of great information in the forums. I may actually end up with a nice shop after all.

Thanks for the help!
Kent

 

[Highdefcowboy]

One more note about the heater roll out switch problem....
My Venturi is pinched at the top. I have a new exhaust blower fan and motor (where the impeller isn't trying to get off the shaft) and .....
I still trip out if it runs too long.
That is if the garage is allowed to get too cool and the heater has to run too long it will trip the roll out switch....
Hmmmm,,,,,
Garage was 47 today, turned on heat to bring it to 60..... at 59 it was blowing cold air and tripped the roll out.....what it did find is that if I keep the minimum temp in the garage at like 53-54 then life is good and I don't have my tripping problem.....
(Tried swapping the upper and lower switches too to see if it is a bad switch and nope.... seems to just be a bad location..)
It's possible that a furnace guy would say it needs a higher temp rollout switch in the top location.... maybe that's the fix...

 

[sprintquicker]

Glad to find this post. I converted my garage into a gym for my training - I'm going to be using the big maxx as my main heat source.

I'll be a lurker in the next few weeks for sure!

 

[Blk04Snake]

Not sure if I'm a bad guy for resurrecting this thread but I am having a problem with the MHU50 Big Maxx heater we bought for a building. They only come set up for NG now and you have to do conversion if using LP. I also have the MHU80 in my garage and that one came set up for LP from the factory. On that unit I have never had any problems except the hose for the pressure switch plugged up once and I got the 2 flash code. Cleaned out hose, killed power then turned back on and flawless ever since.

On this MHU50 it's been trouble right out of the box. All it came with was the conversion for the gas valve (spring and cap). Hooked up, and would constantly trip the flame rollout switch (4 flashes like everyone above). Ordered the correct orifices from Mr Heater (the 047 is listed for LP) and problem appeared to be solved. However, now the unit will run for a few minutes, then the gas valve shuts off, almost like if thermostat was shut off, then it reignites a minute or two later, runs OK for a few mins, then repeats this cycle. Never get any error flashes on the board, and it never runs long enough to get good heat. Propane Co service man came yesterday, tested pressures and they are perfect at 10" wc at the valve test port. Any ideas? Bad board possibly??

 

[bobbyjean]

some posts on this thread seem to indicate poor location of a safety switch for hi temp-the wiring schematic may show the wire's feeding this switch-do you have a multi-meter?

 

[Blk04Snake]

It's not the safety (high flame or rollout) switch. That problem we had early on and would get the 4 flash code and would have to reset the switch. Now it just randomly shuts the gas valve off and not getting good heat out of it. No codes. Also just replaced the board thinking it may have been faulty but still same problem. Almost like it's not getting good combustion or something. Exhaust stinks.

 

[bobbyjean]

huh....weird...how about the flame sensor..power down remove..carefully and take some medium grit sandpaper or steel wool to it...did the propane guy test the maniflod pressure while running? 10" in ... did he mention pressure out? i did hear they will send out a new board without a big hassle..think i priced it when i got my unit...around 65 bucks if not in warranty period

 

[Partsguy57]

More to add mhu80 went to fire up very first time four fast flashes.. I checked the three limit switches all good. Called mr heater after talking with tech and checking some stuff out he decided it was a bad board. Today new board I installed same issue 4 fast flashes . ( open limit switch code) followed the loop of limit switches ( blue wire one end orange other end at connector on board) I stuck my continuity testers leads in the connector to test the loop the orange wire was not fully seated into the connector and when plugged into board left the limit switch loop open and throwing the code. If having issues on new start check all the connections to the board in the connector. ( poor picture on my part, look at upper center part of board, orange wire as this was the problem connector ) cheers

Sent from my SM-G965U using Tapatalk

 

[ponjohn]

This thread may still be paying dividends. I purchased a 75k 12 years ago. Life got in the way, adopted my great-nephew etc.

Today I got the heater running and it it prematurely shuts off. I will be investigating if the burners need to be crimped.

I will report back.

 

[ponjohn]

The document provided above fixed the problem. In addition for future reference, before the fix the tubes were 220 degrees f. After the fix the temp went up to 380-440.