I was on a call last night that I still cannot figure out. It is an 8 year old Rheem RGRA classic 90 that does not want to drain. It is a right side drain into a condensation pump. Here is what I have

- trap installed on right side of furnace
- hose from flue installed on front port (would be back port on left side drain)
- hose from secondary installed on rear port
- hoses tight, no water leaking
- 1/2" pvc from trap comes out into a tee with 5" breather coming from top
- 1/2" pvc goes from bottom of tee into condensate pump, barely in pump, not below water level
- Furnace will run fine until water backs up into collector box causing drain pressure switch to open
- after furnace faults inducer stops, as soon as inducer stops water drains out, furnace will then recycle
- hoses and trap clean

I'm wondering if there is a crack in the collector box allowing air to be sucked in overcoming the trap. Does anyone have any ideas?

 

Welcome to the forum! Here is a link to the installation manual:

http://www.allreds.net/WS2/docs/rhe/rgrs_manual.pdf

Condensate drain information starts on page 32. Did you ensure the condensate trap was clean as they tend to accumulate gunk inside and need to be flushed out on a regular basis?

 

I appreciate the manual. Unfortunately the trap and hoses are as clean as can be. Like I said in my post the unit will drain once the inducer stops running which leads me to believe it is pulling air in from somewhere it shouldn't be. I can visually see water in the trap on the exit side, but it is not coming out, it just sits there as if there is a vacuum on the other side that the trap cannot overcome.

 

I suggest inspecting the collector box and gasket for any cracks or breaches.

 

Thanks for the reply. That is what I'm thinking, I was hoping someone on here would have run across the same problem at some point and found a bad collector box. I just hate to pull the whole heat exchanger out if I don't have to.