Bosch inverter heat pump question.

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Is that the across the line of the compressor startup amps- not taking into consideration the inverter? I was expecting quite a bit lower startup amps.

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I’ve read up on Bosch Inverter units, interested in the system myself, and I’ve read some pretty good things about them. A few negatives, but then all brands/models have negatives.

I’m kind of not understanding your question though in regards to “not taking into consideration of the inverter”. Is your concern being able to run the unit on a generator you already own during power outages?

Understood. Though you are correct that the stated LRA for the Bosch 2.0 5 ton inverter unit is 52 amps and the RLA 29 amps in their product literature I found these 2 comments from Bosch IDS 2.0 inverter owners from 2 different websites and these quotes are verbatim.

“ I recently installed a Bosch 2.0 (seer 20) inverter Heat pump with variable speed compressor and it has absolutely no surge at all starts off at less than 2 amps and ramps up slowly from there the indoor and outdoor fans likewise (both have ecm motors) . it also has good low temp performance.”

“ I have oversized a generator for this house to handle the hard start of the A/C compressor of over 80 amp inrush. With a ramped inverter, and using a Fluke Clamp-on Ammeter, the starting current for this Bosch system begins at 3 amps and builds slowly to about 12 amps nominal load. THERE IS NO INRUSH WITH AN INVERTER. It is an extremely soft start.”.

So these comments by these 2 persons are in line with your personal experience with 3 phase variable speed drive motors. And it has been my understanding perusing HVAC websites that variable speed inverter driven HVACs have low start up amps and ramp up from there. Not being an engineer I can’t square that the higher LRA they state in their product literature.

Why don’t you try to contact with Bosch technical support LINK and I bet you can can get the correct skinny.

Maybe even a HVAC Supply distributor that sells the Bosch IDS units to HVAC installers can provide you with the details you need. About 6 months ago I was in a HVAC Wholesale Distributor to buy some duct mastic and they had operating Bosch IDS 2.0 5 ton heat pump inside the lobby for demonstration purposes. Amazing how quiet those units are when running. The guy behind the counter was very familiar with it and I bet he spent 1/2 hour with me explaining the merits and functional operation of the unit but we didn’t discuss inrush start up amp draw.

Lol, I talked to my local distributor's tech guy today and you just gave me more information with those two quotes than he was able to. I'm definitely getting the equipment for the Casa, but will want to check a few things before committing them to the barndo.... Thank you for the info.

I’ve watched a few YT videos where HVAC techs have installed them in their personal houses. At at least 1 tech on the HVAC talk forum that has installed them for sometime has stated he and customers have been happy with their performance and reliability to date.

They are, as I understand a good bit, cheaper than domestic inverter HVAC systems. A negative for some is that they are manufactured/assembled in China although I think the Mitsubishi inverter compressors are manufactured in a different southeast Asian country - I forget which one.