FHP/Bosch ECM program settings

Discussion in 'Maintenance and Troubleshooting' started by euler7, Apr 27, 2012.

  1. euler7

    euler7 New Member

    Does anyone have any knowledge of the program tap settings on the ECM boards of FHP/Bosch heat pumps?

    I posted a related query a few days ago about the ADJ jumper pin block and how its tap settings can be used to adjust CFM globally (heating and cooling). When I examined the ECM board today to try the ADJ (-) tap setting to decrease CFM, I noticed there are also tap settings for COOL and HEAT jumper pin blocks separately. These tap settings are labeled A, B, C, and D.

    The FHP install manual makes scant mention of these other than to recommend a particular setting depending on the unit model (in our case, AP061 for which the manual advises using tap settting A). My curiosity was aroused (dangerous) and on a lark I checked out the technical literature for ClimateMaster's TT series (the equivalent to FHP's AP and Bosch's AT line). The CM literature is more expansive about the ECM programing and lists how the COOL tap settings (labeled 1, 2, 3, and 4 in their nomenclature) can be used to select different CFM programs that affect cooling mode only.

    The thing I like about that is it does not affect CFM in heating mode. As others advised on my prior thread, my making a point to reset the global ADJ tap setting from (-) to NORM (normal) is not a big deal and I can live with it. But I was intrigued by the COOL tap settings and the increased CFM control they afforded for the CM units.

    The other interesting thing is the CM also has the equivalent ADJ jumper pin block and advises that it can be used to fine tune CFM, presumably only after playing around with the COOL or HEAT tap settings.

    The CM tapping setting 1 results in the lowest CFM, while tap setting 4 is highest. I was curious whether the FHP tap setting A (the one the FHP manual advises using) is equivalent to CM's tap setting 4. In which case, selecting tap setting B on the FHP would select a program with the desired lower CFM in my case.

    I emailed FHP support about their COOL tap settings but as yet have not heard back.

    Thank you.

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