Are there any burner upgrades for this furnace? Ruud mod 90 ser#bu5707 m46921326. The screen is burnt off it and the tech says the part has been discontinued. Thanks for any help. Lou

Explain screen. Where is it located and what does it do.

The screen contains the flame. The flame ignites inside of it. I am not sure if the screen was originally open on the end or not. The burner seems to be constructed kind of in the same manner as a brush burner torch but instead of a tube carrying the flame away from the gas port, this was a tube shaped screen.

I wanted to go online and get a diagram of this unit and get the part number myself so I could search for it directly. The tech that wes out and looked at it says there are no parts available and that I need a new furnace. The problem with was when it tried to ignite it would pop several time very loudly, and shake the whole furnace. It is igniting, but so violently it is blowing its own flame out then igniting again. Sometimes after a few tries of trying to get it going, it might take off and burn but it rumbles very loud as it burns. The tech tested the gas flow and pressure and made sure the air intake had no obstructions. The burner unit in this model is a bolt in unit. It inserts into the combustion chamber and has a ring of bolts securing it into the chamber. Thank you... Lou

I need and exact model number as stated on the furnace. The model 90 has been used for years.

Ruud mod 90 ser#bu5707 m46921326

I cannot locate the correct model with just mod 90. There has to be more to the model number than that. The serial number I do not need right now. Try the model number aghain.

See if these look like what you have.
ruud furnace burners - Google Product Search

Where else would it be located? We know the furnace was manufactured in 1992. It only says ruud model 90. I am not sure if the serial number I have listed is the entire number or if the last part, the M46921326 describes the model better. The HVAC tech is vague on any information and that is why I don't trust him. But once he found out I am searching the internet for the part he came down on his price from 6500 to 5000 for a new unit. But I still don't trust him. I would like to find a new part for 3-400 dollars. He even said the furnace we have is in great condition for its age but the part we need is unavailable. I do appreciate the help... thanks Lou

By law there has to be a sticker or plate on the front of the furnace or side that says

Model
Serial
BTU capacity
VOLTAGE
And other stuff.
I cannot be of more assistance so good luck with your venture.

The pictures in the link does not look like what we have. I don't have the burner assy here, it at the summer home and I won't be back there until Saturday. Otherwise I would post a picture of what I have.
My burner assembly is a flat steel plate that bolts to a flange to make kind of like an inspection cover on the combustion chamber. Through this plate passes the gas inlet... on the other side of the plate, in the combustion chamber there is a nozzle about 3 inches long and approx 3/4 to 1 inch in diameter. Around this nozzle there is a screen about 3 inches in diameter, but it is burnt off out near the end if the gas nozzle. I use the term nozzle loosely but not to be confused with the orifice... of which I did not see exactly where it is located.

Thank you... I'm sorry I am not closer to the unit so that I could search for the information better. Lou

No problem, when you do get back to the furnace, take some pics and let us have a look, I'm curious to see what you are talking about. Also, once you find the complete model number, hvac1000 will most likely have some more input on your furnace.