Posted by: @mike-h

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My Teva out sensor is also showing -50, so this may be normal or we both have faults!

Mine is the same, I suspect they did not fully "port" the code for the UI from wherever they originally took it.  I did read somewhere that the Gen6 heat pump does not have this sensor installed, can't find that reference now.

Posted by: @iantelescope

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Where can I get a SAMSUNG Control PCB with a working PWM Driver?

I put a scope on my PWM output (even though I don't have a PWM pump).  It does send a PWM signal but mostly sits on max.

There are two types of PWM profiles, I see you have the Grundfos PWM Hybrid FLEX which support both profiles.  Make sure you have the correct profile set on the Grundfos, otherwise the Samsung will likely detect an issue with PWM and switch off the PWM.

I ended up having to use a scope to see what was going on with the PWM, then discovered my pump setup was PWM type C, rather than A, which explained a lot.  As soon as I convert this over to PWM type A (I have the kit, just not installed yet) I will connect the scope and let you know what I find.

@william1066  A scope on the PWM Pins on the SAMSUNG PCB.

A good idea.I will try a scope on the PWM outputs from the SAMSUNG PCB. 

The Grundfos motor instructions also say that the Motor will detect a PWM Signal by changing the LED frequency of Oscillation to 12 HZ.

With no PWM signal the Grundfos will revert to maximum power displaying an LED frequency of 1 HZ.

My Motor always stays at 1 Hz, indicating no signal.

When you say you can switch from  P/V "A" to "C" I assume you are pressing the Grundfoss switch ?

many thanks ian

@william1066 PWM on SAMSUNG Heat PUMPS

I have put a scope on the PWM output signal from my Control PCB but can see No Signal!......only noise.

I have the correct PWM Motors with PWM and the correct cable fitted between the Control board and the motor.

I have tried with , and without, Weather compensation to no effect.

I have tried Switching between the Water flow and the indoor sensors again to no effect.

I have to agree with a blushing SAMSUNG ENGINEER who could not explain why so many of the Samsung Heat Pumps do not have working PWM motor drivers.

Your observation that your working PWM signal spends most of the time at maximum was confirmed by the blushing SAMSUNG ENGINEER as  "perhaps" one of the reasons for the failure of this PWM system.

The Operating range of the PWM signal does not correspond to that required by the motors, with the motors spending most of the time operating at, or near,  Full power , Zero volts on the PWM Signal.

ian

ps. SAMSUNG have some questions to answer!.............Why does the PWM system not work on many SAMSUNG HEAT PUMPS?

@grahamh 

Just found your book on Amazon.....bought it immediately.

Your point about the obsession with COP to the total exclusion of efficiency is well made...............

My Heat pump boasts supposed COP value well above 4++, but, after passing though an incompetently installed Heat exchanger the result is a REAL COP of less than 3, all this for a heat pump that does not work below +3 C and is fatally uneconomic during winter!

iantelescope

thanks for buying it, its a little lower level than this discussion. 

The pwm function people are looking at is interesting. its a great idea, see here for description of how its supposed to work https://www.linkedin.com/pulse/pwm-pumps-why-varying-speed-water-good-idea-graham-hendra/ but it doesnt actually do much. Most heat pumps (but not all) dont actually vary the flow rate at all or more than a few percent. Mine runs the water pump flat al year round despite having a pwm pump controlled by the unit. the compressor speed varies a fair bit but 40-100% is pretty much all they do these days. In the bad old days outputs below 10% were normal but not anymore, in my book its a step backwards but what do i know?

Posted by: @iantelescope

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I have put a scope on the PWM output signal from my Control PCB but can see No Signal!......only noise.

You need to enable PWM in the settings.  Check FSV #4051 for more information.

I also found a new version of the samsung manual online, seems to have been updated in Dec 2022.

MIDSUMMERWHOLESALE.CO.UK "https://midsummerwholesale.co.uk/pdfs/ehs-install-guide-samsung.pdf"

@william1066 Field value 4051/2 etc

Thanks William. I found , and experimented with, the 4051 setting some time ago . Unfortunately the PWM system did not start when set to either 70% or 100%.

I have just tried it again , without success.

I am beginning to agree with the visiting SAMSUNG ENGINEER that the PWM system may not be used because , in use , the Pump motor is only varying by a few per cent, a suspicion support here by Graham Hendra.

The Continuously running PWM motor would , however, greatly reduce the energy consumption , reduce relay arcing and increase motor reliability as shown in the excellent YouTube video .

 The Visiting SAMSUNG Engineers solution to the arcing relays , i.e. fitting another,  bigger relay in series with the PCB Relay( as shown on pg 23 of the old manual) is not an idea I would go for. Unreliability multiplied by two.

ian

Posted by: @iantelescope

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Unfortunately the PWM system did not start when set to either 70% or 100%.

I will do some tests on this, but I suspect that there is a point where the samsung control logic decides you don't actually have a PWM pump and disables it, regardless.  I hope to revisit this soon as I now have the correct converter to convert the HEATING PWM signal into a 0-10v (which my pump needs).  Previously I was converting the heating PWM into what was effectively a Solar thermal response as my PWM to 10v converter was inverted [relative to what was needed for a heating circuit]

Posted by: @iantelescope

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the Pump motor is only varying by a few per cent, a suspicion support here by Graham Hendra.

The manual says that it will only move from 50-100%.  Again, once I get mine installed I will monitor the 10v signal coming out of my PWM to 0-10v converter, log it to home assistant it and share the results.

@william1066 the manual says alot of things but i was always told dont believe all the lies you are told.

@iantelescope PWM was released on gen 6 units about 5 years ago, i had one installed so i could train people on it. the PWM signal doesnt do anything, we tried every setting in the book, it was our job. The PWM doesnt do anything except limit max speed of the pump, likewise on pretty much every heat pump ive ever monitored. Ive only seen it work properly on one unit RED. but thats another story for another day.