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Mark Trimble
Mark Trimble,
Category: HVAC
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Experience:  Owner at Self employed
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I have a Ruud/Rheem RGRC-06EMAES furnace made in 2011 Oct.

Customer Question

I have a Ruud/Rheem RGRC-06EMAES furnace made in 2011 Oct.When it tried to start up, the ignition sparks could be heard but no flame appeared indicating that the gas valve was not opening. Studying the diagrams, there are many sensors that have to be happy before the gas will come on. It was straightforward to isolate the problem to the “Drain system pressure switch” which would not close. To determine if the problem was with the switch or the “pressure” source, I used tubing from a stethoscope to apply mouth pressure to the switch with an ohmmeter connected. The switch closes when a very slight vacuum is detected, probably “-0.40 PF” as read from the label on the switch.As a unit of pressure, PF is an archaic unit used in agricultural science to measure "soil suction" or soil moisture tension.
See: https://www.unc.edu/~rowlett/units/dictP.html.So this vacuum switch appears to be OK. I blew into the red tube apparently coming from the low point in the heat exchanger to drain off combustion condensate. I sensed very slight resistance to blowing into this tube. Nevertheless, I must have dislodged something inside the heat exchanger, because the vacuum switch and consequently the furnace have been working for days after doing this.I’m surmising that some kind of crud must be inside the heat exchanger. There are many dead insects (gnats?) on the horizontal surface that separates the upper and lower sections of the furnace. Are these also in the heat exchanger where they might have been seeking water?My prediction is that the furnace is going to shut down again in the same way it recently did. But I have no idea how often this might occur. I want to pursue this, but so far I see no reasonable way to gain access to the interior of the heat exchanger. I thought I might be able to remove the induced draft blower. But some pictures of the heat exchanger show a much smaller hole facing the input to the blower than would be useful. What is the best way to inspect the floor of the heat exchanger, especially near where the condensate drain attaches to it?If I need to clean some crud out, how can I get access to do so?If I have to remove the induced draft blower, where can I buy the black rubber caulk that was used to seal the connection to the exhaust of the blower?
JA: Did you double-check the thermostat's settings? And what about the filters?
Customer: Please read my text before responding!
JA: Do you plan on doing the work yourself?
Customer: Yes.
JA: Anything else we should know to help you best?
Customer: I sent considerable detail in my original question but I can be reached at***@******.*** if you need to ask more.
Submitted: 14 days ago.
Category: HVAC
Expert:  airheatman replied 14 days ago.

So you get a blinking light on control board when it fails to light.If so count blinks between pausing and let me know

Customer: replied 14 days ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  airheatman replied 14 days ago.

I am unable to take phone call right now. This will be presented to my colleagues so you may get a call from one of them if available.

Customer: replied 14 days ago.
I'm ready to talk. Thank you. :-)
Customer: replied 11 days ago.
It is now Jan 10. I have had no further response to my question. :-( I asked to get a phone call from a tech.
Customer: replied 11 days ago.

I can be reached on my cell: *************

Expert:  Mark Trimble replied 2 days ago.

do you still need a answer to your question

Customer: replied 2 day ago.
please!
For the next 3 hours, I can be reached at(###) ###-####or***@******.***. Afterwards, I will be at cwhh@. . . and the same phone.
Expert:  Mark Trimble replied 2 day ago.

condensation was the most likely cause of the problem removing the inducer blower is not going to get the access you are looking for

Customer: replied 2 day ago.
Shouldn't I expect condensation within the heat exchanger? Isn't that what the drain tubing is there to remove?
Expert:  Mark Trimble replied 2 day ago.

no condensation in heat exchanger it comes from the vent pipe

Customer: replied 2 day ago.
OK, so condensation comes from the vent pipe and needs to be drained by the tubing connected to the bottom of the heat exchanger?
Expert:  Mark Trimble replied 2 day ago.

yes there should be a drian line connected to the primary condensation line

Customer: replied 2 day ago.
there is. And it seems that the “Drain system pressure switch” was not closing because the flow of condensate was backing up.
Customer: replied 2 day ago.
We might get this done faster on the phone. :-)
Expert:  Mark Trimble replied 2 day ago.
The drain not flowing could cause moister to collect so make sure the drain is clear that should solve your problem. If you want to talk on the phone you need to make the phone request
Customer: replied 2 day ago.
The drain tubing is clear, so I think the problem is just inside the heat exchanger which the drain tube comes from. That's why I'm hoping to find a way to get a look in there.
Expert:  Mark Trimble replied 2 day ago.
The heat exchanger are stainless you can attemp to remove the inducer motor it's not going to give you much of a view
Customer: replied 2 day ago.
are you saying there is no way to clean whatever insect crud is in there other than to replace the furnace?
Expert:  Mark Trimble replied 2 day ago.
No not at all you can remove the inducer motor by removing the screws that attach it to the furnace and the clamps that attach it to the pipe your not going to see much so with that said your I believe the problem has been resolved with the drain line issue
Customer: replied 2 day ago.
you're saying it's possible to remove the inducer motor. And even though I won't see much, it's my only hope to see what's going on and maybe to clean it?
Expert:  Mark Trimble replied 2 day ago.
Customer: replied 2 day ago.
OK. This weekend I want to remove the inducer motor and see what I find. May I continue (and hopefully finish) this thread at that time?
Expert:  Mark Trimble replied 2 day ago.
No I have resolved your issue if you want to continue to move forward with your assumption feel free

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