In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
The Munchkin 80m walk of shame.
I'm here because I reached my limit. This unit has been taunting me for several years. I've used the search function and still cannot solve this riddle. Here is the abridged history of me and my Munchkin.
I designed the heating system (radiant and wall hung Buederus) and installed the 80m propane unit myself in Nov of 2004. The piping is primary secondary; the venting is concentric through the roof with minimal fittings, the gas line is 3/4 iron with drip and the press drop is within the spec. The unit was adjusted in Jan of 2005 by Mark Hunt; he gave me a pat on the back for a job well done.
Two years ago the F09 codes started arriving at an increased rate. I cleaned the probe to push the issue down the road. Fall of 2010 I had a tech come in and service the unit: cleaning, new probe, etc. He can't get the unit to consistently fire and run quietly after reassembly. He spends time on the phone with HTP and has a new part sent (venturi assembly perhaps). He gets the unit adjusted and working pretty well. I say 'pretty well' because it still occasionally set a F09 or F10 code throughout the 10/11 heating season and even less often over this past summer and fall.
This week the cold weather arrived here in upstate NY and the fault codes came with it. I pulled the probe and cleaned with to no avail.
I checked the d7 mA output on the display and find that low fire is at 0.8 instead of the spec of 1.0.
Tonight, I replaced the flame rec. probe with a new part. No change; still producing codes.
In order to get the unit to stay in cycle, I cheat the computer by wiring in a 9.0v battery in parellel with the rectification probe. I have to manually make the connection to the battery at the right time to make it work. Once it runs for 30 sec or so, I can disconnect the battery and walk away. The high fire mA is 3.8 to 4.0.
I will gladly call my tech again, but I need some ideas or areas to check.
Just to clarify:
Last year, I personally connected my digital press. gauge to the drip leg to verify the static and dynamic pressure. Can this change due to regulators going out of range? Should the press. be dialed up to the max allowable to rule out any issue with press. drop?
thanks for reading,