Big Maxx MHU45 glowing red

[David4321]

I pulled into the garage last night and the garage door opener lights did not come on. In the darkness I noticed that the heat exchanger tubing on my big maxx heater was glowing red hot while in operation. I never would have noticed it with the lights on. They glow red at the point where they make there first bend and go back into the heater. Is this normal for the unit? The fan is working and the flames seem centered in the tubing and are blue in color. The only thing I can think of is that the manifold pressure may be off. The altitude here is a 3500ft. The data plate on the unit says 4.0 inches for 0-2000ft and 4.0 inches for 2000-4500ft and to adjust only if you go above 4500 ft. The instruction manual with the unit contradicts this however and states that 0-2000ft =4.0inches 2000-4500 =3.6inches. Perhaps I should lower the manifold pressure. Has anyone else noticed this red glow when the garage is dark? Is it normal? If not what did you do to fix it?????

 

[tim096]

My 75000 turns red too I believe this is normal.

 

[David4321]

Well I have heard some say its bad, others say its normal. I am going to try to adjust the manifold pressure to 3.6 as per the instructions in the manual and see what happens as the altitude here according to my gps is 3600ft. Problem is I need a monometer to do this. They are ****** expensive for a digital one!!!!! So here is were it gets interesting. I have found that you can make a "u" shaped water manometer for about 5 bucks in parts from home depot. This should be fun I'll let you know how it goes and if it works.

 

[rickairmedic]

Dav e you can get a real water monometer from n HVAC supply house pretty chep try to find a real one before making one as they are marked properly .


Rick

 

[BillK]

David,

Although I will generally try to fix almost anything .... there are certain things that I will not touch without calling the manufacturer first. A gas furnace is one of them. There is too much at stake to just be taking wild guesses as to whether the condition is normal, and if it is not, what to do to correct it.

Just my opinion,

 

[Chetter]

I would contact the manufacturer, Mr Heater, and talk to their tech dept. They helped me with my questions when I was installing a Big Maxx 45000 btu LP unit this fall. Save yourself a lot trouble before you change anything for what it is worth.

 

[David4321]

Well got the manometer and adjusted to 3.6. Alot better but still glowing red while running. I called mr heater last week but they were closed for the holidays of course so hopefulloy i will hear from them on monday. If not I have a gas fitter that is going to come by later in the week and let me know if all is well with it. I'll keep you all updated thanks for the replies.

 

[Mellotron]

What did you find out?

How many of you out there have had their heater adjusted for altitude. I'm terribly curious...

 

[BigChevy80]

What did you find out?

How many of you out there have had their heater adjusted for altitude. I'm terribly curious...

I'm in the flatlands of IL so altitude isn't really an issue for me, but my 45,000 BTU Beacon-Morris unit glows red too. Same place as the original poster described, right at the first bend of the heat exchanger.

I think it's normal.