MarkBarrett
New Member
Hi everybody,
I'll start by saying I am not knowledgeable in HVAC. Never worked in the field. I have decent analyzing skills, as I am a newly retired system integrator in industrial electronics. My question is why is my temperature rise approximately 15 degrees F less on HI fire than on LOW fire?
Here is a run down of my furnace specs:
1, Furnace is a Goodman GMV90703BXA
2, BTU output 64,200 High fire, 44,600 on Low fire
3, Temp rise F 30-60
4, Skuttle model 216make up air unit
We bought this newly constructed house in 2006 as a second home. Since the summer of this year it is our main home.
Observations of furnace performance:
1, Many hot air plenum leaks. No tape on top, an 8 inch hole that wasn't covered on top of plenum etc. These were fixed.
2, Temp. rise not even 30 degrees. Temp rise taken at just before filter on return side and out of the line of sight on the supply side.
3, Thermostat wired for 2 stage operation, but wasn't programed for 2 stage op. Rectified that. Ran on Low fire for 5 years!
4, With a 35 degree outside temp, recovery time is approximately one hour to raise house temp 4 degrees (64-68 on low fire).
5, When calling for high fire, inducer blower and circulation blower run at high speed.
Things I changed and checked:
1, Slowed blower speed for a temp rise of 50-60 degrees on low fire.
2, Using a multimeter, got 24vac at N.O. contact of high fire pressure switch to 2 stage valve when on high fire.
3, Make up air unit adjusted for low speed blower operation.
Sorry for the long post. Any ideas as to why temp rise is less on high fire. Your help is appreciated.
Mark
I'll start by saying I am not knowledgeable in HVAC. Never worked in the field. I have decent analyzing skills, as I am a newly retired system integrator in industrial electronics. My question is why is my temperature rise approximately 15 degrees F less on HI fire than on LOW fire?
Here is a run down of my furnace specs:
1, Furnace is a Goodman GMV90703BXA
2, BTU output 64,200 High fire, 44,600 on Low fire
3, Temp rise F 30-60
4, Skuttle model 216make up air unit
We bought this newly constructed house in 2006 as a second home. Since the summer of this year it is our main home.
Observations of furnace performance:
1, Many hot air plenum leaks. No tape on top, an 8 inch hole that wasn't covered on top of plenum etc. These were fixed.
2, Temp. rise not even 30 degrees. Temp rise taken at just before filter on return side and out of the line of sight on the supply side.
3, Thermostat wired for 2 stage operation, but wasn't programed for 2 stage op. Rectified that. Ran on Low fire for 5 years!
4, With a 35 degree outside temp, recovery time is approximately one hour to raise house temp 4 degrees (64-68 on low fire).
5, When calling for high fire, inducer blower and circulation blower run at high speed.
Things I changed and checked:
1, Slowed blower speed for a temp rise of 50-60 degrees on low fire.
2, Using a multimeter, got 24vac at N.O. contact of high fire pressure switch to 2 stage valve when on high fire.
3, Make up air unit adjusted for low speed blower operation.
Sorry for the long post. Any ideas as to why temp rise is less on high fire. Your help is appreciated.
Mark