Older Samsung EHS Mono - SNET-Pro (non-NASA) for monitoring?

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Hi All,

New user here, hoping to get some advice from a community of experts.

I inherited an ASHP through a property purchase a few years ago, so a complete novice who has been attempting to self-educate. I’ve made good gains to-date from research and trial-and-error control panel adjustments etc. and am now at the point where I need a view of system data over time.

I recently found @SarahH 's thread “Monitoring Your Samsung ASHP Controller” which has been a great source of info, but it’s written around the newer MIM-E03*N controllers and SNET-Pro2. My heat pump is an older generation, so I’m not sure how much of it applies.

My system:

  • Outdoor unit: Samsung RC090MHXEA (9kW monobloc, UK)
  • Control kit: no model number visible on my indoor board. Samsung’s installation manual for this outdoor unit names the MIM-E03A as the required control kit, and my control kit manual is reference DB98-34412A(1)
  • Service documentation I’ve seen describes this range as dating from 2010-2015

What I want: read-only monitoring so I can understand how the unit behaves against outdoor temperature over time (flow/return temperatures, pump state, anything the controller reports). I’m not looking to control it, and I’d like to avoid changing any settings through the software.

What I’ve found:

  • A reply in that thread suggests older non-NASA heat pumps might need SNET-Pro rather than SNET-Pro2, which also connects at F1/F2.
  • Samsung’s own SNET-Pro download page describes it as service software for DVM Plus I/II/III and FJM systems. It doesn’t mention EHS heat pumps, so I can’t tell whether it supports my unit.
  • The heat-pump-specific ESPHome NASA component lists newer MIM-E03CN/DN/EN boards and says older non-NASA systems aren’t supported.

Questions

(disclaimer - I’ve been using Claude AI to help me with this - some of these are AI-suggested - don’t assume I have any significant system/install knowledge! Although on IT/Network/Software side in general I’m relatively competent)

  1. Has anyone used SNET-Pro (not Pro2) with an RC090MHXEA, or any EHS Mono with a MIM-E03A?
  2. Does that generation use NASA, NonNASA, or something else on F1/F2?
  3. If it does work, did a cheap USB RS-485 adapter on F1/F2 (similar to the Waveshare one in the thread) do the job, and what data did you get (water temperatures, flow, pump state, refrigerant-side values)?
  4. Is it safe to leave an adapter connected for a monitoring run, and any tips on avoiding accidental writes?
  5. If SNET-Pro doesn’t support these units, did anyone get data out via Samsung’s Modbus module, or is clip-on flow/return sensors plus a CT meter on the heat pump circuit the sensible fallback?

Would be grateful for any advice from the experienced community here, before I go ahead and spend some time & money on a basic proof-of concept.

Thanks,

Mark

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Welcome @markjwilliams321 - unfortunately I couldn’t find anything specific for that module. In the service manual, there is a reference to RS485 inputs. My suggestion would be to pick up an RS485 adapter and see if any of the existing integrations work at all. Hopefully they wouldn’t have changed the register layout between generations. Not too helpful, but that would be a reasonable place to start :slight_smile:

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Thanks for the reply @awjlogan - I’ve gone ahead and done just that, so will feed back here on results, after attempting setup and initial test etc. over the weekend - I’m starting from scratch here so need to configure the end-to-end (mini PC, VM, software setup etc, as well as the RS485), so bear with me!

Fingers crossed, but if this method is a complete dead end, my fallback option will be to see what I can achieve with isolated component monitoring (Shelly clamps or something similar).