MUA burner profile

[Eric V]

MUA unit with two speed blower,10mbtu direct fired burner,no automatic profile control. Owner claims heat should run properly in high or low speed. My question is how can this be without adjusting the profile across the burner?

[ewang]

What brand of unit? Is there a bypass damper?

If there is no bypass damper, or automatic profile control, then you will have to try to make both speeds work within the differential pressure switch range.

Run unit at high speed, adjust profile plates to be a little less than high range on pressure switch, run at low speed and see if it works.

[superfittertech]

midco burner range .2" w.c. to .8" w.c. pressure differential although you can go higher without making co, but temperature rise will suffer

[acwizard]

MUA unit with two speed blower,10mbtu direct fired burner,no automatic profile control. Owner claims heat should run properly in high or low speed. My question is how can this be without adjusting the profile across the burner?

It is possible as long as gas modulates either with discharge air damper or bypass . Never seen unit with 10mbtuh rating. What mfg is this unit.