How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask airheatman Your Own Question
airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 7758
Experience:  Furnace, A/C and heat pump specialist.
16514686
Type Your HVAC Question Here...
airheatman is online now
A new question is answered every 9 seconds

Have a brand new Tempstar high efficiency furnace set it up

Customer Question

Have a brand new Tempstar high efficiency furnace set it up hook it up and when I turn it on or jump the White and the red it sounds like the pressure switch clicks the first fan goes on and then nothing happens after that and I get 3 flashes from the indicator light
Submitted: 3 months ago.
Category: HVAC
Expert:  airheatman replied 3 months ago.

What Is model on unit?

Customer: replied 3 months ago.
Nm9se401410a2
Expert:  airheatman replied 3 months ago.

OK if you keep a vacuum sucked on the pressure switch will the gas valve open?

Customer: replied 3 months ago.
Not sure sounds like it clicks on its own when I fire it up.
Expert:  airheatman replied 3 months ago.

Try turning to HEAT, suck on hose and as soon as you hear pressure switch click, check for 24 volts at gas valve

Customer: replied 3 months ago.
Not sure I have that many hands let me check it out
Expert:  airheatman replied 3 months ago.

Standing by

Customer: replied 3 months ago.
If I'm doing this right with my multimeter I only have about 11 volts coming out of the why are going to the gas valve
Customer: replied 3 months ago.
Hello
Customer: replied 3 months ago.
Now we are at 14 volts
Customer: replied 3 months ago.
R u still there
Expert:  airheatman replied 3 months ago.

If pressure switch is closing and you hear it click you may have a defective board even though new if board does not send 24v to valve.Try unplugging wires from pressure switch and reconnecting to make sure connections are good so board sees switch is closing.

Customer: replied 3 months ago.
Just did that just to make sure I'm doing this right there are two tubes coming off the pressure valve one goes to the inducer motor and one goes to the condescend pump I want to suck on the one going to the inducer motor from the inducer motor and correct
Expert:  airheatman replied 3 months ago.

THat is correct.The inducer is what pulls a vacuum on the switch. Now if unit had been running we might have water backing up preventing switch from getting vacuum, but since this is new, that should not be the case.The board signals inducer to come on,Inducer comes on and pulls vacuum on switch.As soon as switch closes, it signals board to send24v to valve and burners light.As soon as burners light flame sensor signals board it is ok to stay on and energizes main blower.If it fails anywhere along the way we get a fault code. In our case the code is saying switch is still open

Customer: replied 3 months ago.
when it clicks is that mean it's opening or shutting? Because when I stop sucking it on clicks should I continue to suck while I'm doing this
Expert:  airheatman replied 3 months ago.

It will click when opening and closing.You need to keep a vacuum sucked constantly to keep it closed.

Customer: replied 3 months ago.
It is staying closed I I am getting anywhere from 7 - 11 volts going to the gas valve so that's gotta be the problem I guess I should call from warranty service
Expert:  airheatman replied 3 months ago.

Yes, the board is not sending enough voltage to open valve

Customer: replied 3 months ago.
One last thought I am feeding us with a half inch gas not 5/8 or three quarters that shouldn't be a problem should it it's just half inch the last like 2 feet of the pipe and the flexible housing
Expert:  airheatman replied 3 months ago.

1/2" gas line is plenty sufficient unless your meter is over 100 feet away from furnace.But regardless of pressure, gas valve will not open until it gets 24v.If pressure were the problem, valve would open, burners just would not be hot enough to keep flame sensor warm.

Customer: replied 3 months ago.
Cool. I will leg you know the final soluyion. Thsnks
Expert:  airheatman replied 3 months ago.

Sounds good.Would like to know results