NT30SP very hot??

[pt1949]

I had my NT30 K furnace replaced in my 92 Excella with the recommended and only replacement - the NT30 SP. Got it all in and had to make some adjustments but it worked. Problem is the heat coming out in the living area. I had to move the vent up a little to accommodate the outlet on the furnace. The air coming out is just too hot! You can't get your hand close or sit with in 4 feet of it. Back and bath is perfect. Any ideas on how to turn the heat down? Thanks

[AtomicNo13]

Showoff!

[idroba]

The only way to decrease the temperature is to increase the air flow through the furnace. Although Suburban says you can use only three 4" duct outlets on an installation, I have found that four works much better. Adding a forth one made the new furnace in my 310 motorhome work much better, even though the original install by AS only had three ducts. I would guess you have the same issue and moving one of the original ducts may have restricted the air flow more.

[ventport]

You could put a small gas jet in the burner. Suburban says a minimum of three 4' duct outlets, not a maximum of 3. My Argosy had 4 outlets from the factory.

[pt1949]

Ah good ideas - where did you put the other vent? I think we may have pinched the rear or the bedroom cause it is a tight fit around under sink storage.

[idroba]

I don't know your specific rig so the location of the extra vent on my motorhome would be of no value to your trailer. However, you can look around and see where a duct might fit and an outlet be placed.

As you mentioned, pinching a duct on an already marginal outlet furnace would make a difference also.

[n2916s]

Does the new install provide for some hot air headed down for the tanks? On my 86, the subfloor is fed right from the front of the furnace.

Mike

[altnbndr]

After you do any work to the ducts of a heating system you should always check to verify the temperature rise and static pressure of the system are within the specs. listed on the data plate or label. Your heater (nt 30 ) should have a temp. rise of between 100/130 degrees at .2 inches static pressure. If your temp. rise or static pressure is above limits then your not moving enough air and you will either need to remove restrictions in the ducts or add more outlets. To take these readings all you will need is a thermometer and a U tube manometer (which you can easily make yourself).

[Tony S]

Is the air coming out too hot with three vents a common thing.

Please let us know if the 4th vent does the trick for you. Good Luck.
Tony