Am I Under-firing my Furnace?

[SBKold]

Thanks guys. Is there only one intech model to look for?

[chuckcrj]

Thanks guys. Is there only one intech model to look for?

http://www.bacharach-inc.com/fyrite-intech.htm

[Hvac216]

I just bought the testo 320. It has a nice color display. I paid $1350 for the kit with the printer.

[BigBacardi]

curious....you said you clocked furnace....u have lo pressure gas...or 2 lb?????

if you have 2 lb did you forget to make allowance for pressure allowance of xxxxxx?

cause if you forget pressure differential it will clock as underfired!!!!

[MicahWes]

I don't know what the pressure before the meter is, if that is what you are asking?

A cubic foot is a cubic foot though, right? My side of the meter is like 16 inches of water.

[54regcab]

Actually, yes! I like long run cycles. Also, the registers are in the ceiling, so I like the discharge air to be cooler to help keep stratification to a minimum. There is hardly any perceptible temp swing now. We have been using the new furnace for a month and it is LOADS more comfortable that my old furnace with it's 150 degree discharge air.

Why did you oversize the new furance? 70K is good for 3000sqft+ in Raleigh, NC if you have decent insulation. People are scared to install a 2 burner furnace as a primary heat source for a house since is so rarely done. A 2 burner furance is what's going in my house when it's time for replacement.

[MicahWes]

I got it for practically free! The house is 2400 sq ft. The old furnace was 140K, so I am moving in the right direction. It is two-stage, so I figured low stage should be just about perfect 90% of the time.

[54regcab]

Cutting furnace size in HALF and it's STILL oversized. That's just nuts...

[perfectionist]

Chuck- do you have any advice for me looking online for good used one for maybe $400-$500.

Would an older fyrite be good for a guy starting out using CA who does only 5-10% combustion appliances ?

I have a TESTO 327 w/ printer and it was $1200 new.

[perfectionist]

I got it for practically free! The house is 2400 sq ft. The old furnace was 140K, so I am moving in the right direction. It is two-stage, so I figured low stage should be just about perfect 90% of the time.

The first stage isn't typically the most efficient way to heat the house. I'm not saying you can"t fine tune first stage but from what I have seen second stage is more efficient.

[martyinlincoln]

Play around with it. Measure BTU in vs BTU out then change the gas pressure and measure again. Do the same with the blower speed while checking the flue temp.Of course you'll need to do all the measurements in each stage. A combustion analyzer makes quick work of it but even without one you'll know what settings give you the greatest efficiency.

[beenthere]

The 1.6 to 2.2" and 3.2 to 3.8" are the allowable adjustment range. This is so you can allow for the BTU content of the gas your supplier provides. Yes, your probably under fired.

Set both stages up by clocking your meter for the BTU content of your gas. And then make minor adjustments as a CA and temp rise may indicate are needed.

[BigBacardi]

pressure correction factor .....if you have anything above lo pressure...14 inches than a pressure correction factor must be performed. standard clocking tables are made with lo pressure data.