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Charles
Charles, Engineering contractor
Category: HVAC
Satisfied Customers: 2066
Experience:  20+ years in the construction industry
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Reznor heater troubleshooting

Resolved Question:

Any idea why my Reznor heater won't fire? It turns "on", but the burners don't fire and the fan doesn't kick on? It's two years old. The unit is not receiving fuel? I have triple checked valves.
Thanks for any help,
Ryan
Submitted: 5 years ago.
Category: HVAC
Expert:  Charles replied 5 years ago.

Hello and thanks for your question!

Are you sure its not getting fuel? Is you unit push button start or electronic start?

Customer: replied 5 years ago.

Hi,

The unit is electronic. I don't hear the click, click, click either?

Expert:  Charles replied 5 years ago.

Ok, it sounds like you have no power to the unit. You say it say on? Is the igniter battery or electric??

Customer: replied 5 years ago.
It's electric. The unit physically turns on when I turn the thermostat on and increase the temp, but it simply sits and hummmmms....
Expert:  Charles replied 5 years ago.

It sounds like the gas valve is not opening. I would double check the valve and make sure all the valves are lined up with the pipes.

Is this how they are??

Customer: replied 5 years ago.
Yes, two valves involved and both are in-line. Is there any way moisture in the "T" just before the regulator is the problem?
Expert:  Charles replied 5 years ago.
Only if it plugged up the line. Has there been a problem with that before? Is this natural or Lp gas?
Customer: replied 5 years ago.

No problem with that before, just threw it out there as a possibility? Natural gas. How about a faulty thermostat. When I turn up the thermostat and then go over to the unit the green light blinks steadily on the inside panel, FYI.

Expert:  Charles replied 5 years ago.

That was my next idea. This should be a basic Tstat. Is it digital?? Can you pop the cover off the Tstat??

Customer: replied 5 years ago.
Yes, basic digital tstat. Cover is popped off...
Expert:  Charles replied 5 years ago.

How many wires? What colors?

Customer: replied 5 years ago.
2 wires, red into RH and white into W
Expert:  Charles replied 5 years ago.

Ok, remember where those wires go and remove them, Then touch them together, If the Tstat is bad then the heater will start. If it still will not start then the Tstat is ok. If its good then put the wires bac where they go and cloce up the Tstat,

Let me know what happens.

Customer: replied 5 years ago.
Alright, I'll be right back. FYI, I have had this heater for two years and it's been just fine. Standby...
Expert:  Charles replied 5 years ago.

Ok

Customer: replied 5 years ago.
Same as before, just the exhaust fan starts when the two wires are touched.
Expert:  Charles replied 5 years ago.
When you connected the wires did the igniter make any noise?
Customer: replied 5 years ago.
No noise. Just the exhaust fan.
Expert:  Charles replied 5 years ago.

And you did not get the fan with the Tstat correct??

Customer: replied 5 years ago.

No, I did get the fan with the tstat. No difference between tstat and touching the two wires together.

Expert:  Charles replied 5 years ago.

Ok, its taken us a while to get here but I feel I have it narrowed down for you.

Either the igniter is bad.

Or the control board is bad. I would say that you should check the control board. If it is not communicating with the rest of the system then it will not allow the igniter to spark. Give this a try. Check the board, there should be a light that will flash a code if there is a problem with it.

Customer: replied 5 years ago.
I get 2 green flashes and on the back of the panel it tells me "pressure switch does not close within 30 seconds of venter energized"
Expert:  Charles replied 5 years ago.

Ok, that is your problem. The pressure switch is bad. That is why I wanted you to check the board, the board will tell you if there is a failure.

If you decide to change out the switch yourself let me know how it goes.

I hope this helps answer your question and solve the issue.

Thanks

Charles and other HVAC Specialists are ready to help you
Customer: replied 5 years ago.

You have any suggestions on where to buy Reznor parts? I imagine their website eh??

Thanks for your time!

Ryan

Expert:  Charles replied 5 years ago.

No problem, its been fun working with you on this. I like things that make me think! It gets old fixing the same old issues all the time!!

This one actually made me think allot!

www.rezspec.com/catalog-udbp.html

Thats the easiest way, that way you know its the right part also.

I attached a link to the website for you.