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BillyHvac, Journeyman HVAC Tech
Category: HVAC
Satisfied Customers: 23271
Experience:  Endorsed for unlimited heating, cooling, oil burners, boilers, refrigeration, hydronics
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I have a tempstar DC90 model NUGM075EGA1 that starts but

This answer was rated:

JA: Hello. How can I help?
Customer: i have a tempstar DC90 model NUGM075EGA1 that starts but then turns off often running for about 1 minute
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: For three days now.
JA: Do you plan on doing the work yourself?
Customer: I want to try to fix it myself
JA: Anything else we should know to help you best?
Customer: I noticed a slight smell of burnt plastic in the house when I came home the other night and it was that night that I realized the furnace was not running
JA: Did you check the furnace's filters?
Customer: I replaced the main filter.


Does the main blower that blows heat through house appear to be running as normal?

Customer: replied 8 months ago.

and when the furnace shuts down is there a light on a circuit board that blinks?

Customer: replied 8 months ago.
There is one green light and it blinks

is this light on the gas valve or on the circuit board in bottom?

Customer: replied 8 months ago.
It is on the circuit board

Thank you. Now when first started this light should be solid but when it faults it blinks a 3 for example...and repeats. Do you know what yours does?

Customer: replied 8 months ago.
When I turn the power on it starts to blink but the blink changes once it shuts down

what is blink on shut down?

Customer: replied 8 months ago.
It is a steady blink, I guess I would say it is a one


on this unit bright/dim, bright dim is normal.

a one blink that repeats is overtemp limit fail meaning it is running too hot. Then a limit opens until cooled and then lets it try again.

This can be air restriction (filters)

Bad blower (slowing down)

Blockage in duct ( saw a plastic bag sucked in one time)

vents closed

ac coil plugged on top of furnace if present.

Basically it is an overheat saying not enough air flow.

Start with anything that can slow air in the duct...on these units I have even pulled the blower to remove debris/dust.

Since you smelled something hot, I am betting the limit is doing its job and the furnace is actually running to warm.

Customer: replied 8 months ago.
Ok, I’ll open all vents and also check for any air blockage

make sure blower in bottom running strong

Customer: replied 8 months ago.

just return back here for follow up.

Rate service to move off the active list for now.

Thank you,


BillyHvac and other HVAC Specialists are ready to help you
Customer: replied 8 months ago.
upon further inspection I see that the blower is not running