Samsung Gen 6 PWM pump Connections

[johnfresh (John Freshwater)]

Hi Mike

See below reply from Techsupport

Hi John,

To my knowledge there is no firmware update for POWM pump modulation.

Bear in mind PWM modulation is only active in heating mode with flow temps exceeding 45C.

PWM is not active during the DHW cycle.

Best regards

Nick Kirwan

[MikeJH (Mike Heap)]

@johnfresh

Hi John,

To my knowledge there is no firmware update for POWM pump modulation.

Bear in mind PWM modulation is only active in heating mode with flow temps exceeding 45C.

PWM is not active during the DHW cycle.

Best regards

Nick Kirwan

I don’t see how this fits with Ian’s comment. I have double checked by looking at Ian’s flow rate. On 28th March at 15.28 his flow rate is 28.3 L/min and at 17.08 it is 14.6 and at 21.12 it is 13.1. The flow temperature was never above 36C.

@Ian_Calderbank

if you take a look at my system 45 on HPM this is a large system with a PWM pump, you can see it uses pump modulation to maintain DT. (turn on the "show flow rate option)

[MikeJH (Mike Heap)]

Hi John,

I’ve found the reference to firmware.

[billt (Bill Taylor)]

@johnfresh

Bear in mind PWM modulation is only active in heating mode with flow temps exceeding 45C.

PWM is not active during the DHW cycle.

That’s odd, my 8kW gen 6 is modulating the flow with a maximum temp of 30C.

And something’s controlling the flow rate during HW heating.

[johnfresh (John Freshwater)]

Don’t shoot the messenger

Only relaying message from their support, although the usual guy I speak to is on holiday so prhaps he will add his bit when he returns

John

[johnfresh (John Freshwater)]

Just because the flow rate has gone down doesn’t mean the pump has slowed down it maybe zones have shut down resulting in more system pressure resulting in less flow from pump
Unless obviously they have a completely open circuit

John

[billt (Bill Taylor)]

The system is completely open loop, there are no zones or valves to close. The flow rate in the graphs is the actual flow rate resulting from the pump slowing down. (You can hear the water speed reducing as the flow slows.)

And here is the power to the indoor unit showing reducing power input as the pump speed reduces.

[johnfresh (John Freshwater)]

Not sure what is correct then

Perhaps when Robert Kerr gets back from his hols he will shed some light on it

John

[SarahH (Sarah Hanson)]

Interesting discussion.
I took a look at the MIM-C02N outputs from a a couple of recent test runs. (I have FSV #4052 at the default 5degC even though my circ’n pump is fixed speed.)

1. Nick K is correct that the controller PWM output stays at 100% on DHW.
2. He also (almost) correct in saying that the PWM signal is 100% below an LWT of 45degC. Take a look at this graph (red line):
   
   The x axis is LWT (degC); the y axis is PWM output signal (%).

OK it’s not quite as black and white as Nick suggests, but (by calibrated eyeball) I’d say the signal is still 95% at up to 45degC LWT (but drops like a stone above that).
3. The blue line is actually PWM output signal against (LWT-RWT), though the scale I’ve used isn’t very helpful. But you can see that (as you would expect) PWM output drops strongly as deltaT falls (the raw data shows PWM=40% at deltaT of 2.0degC).
4. I’d conclude from this that if you are seeing measurable circulation flow modulation at a lower LWT than ~40degC, then something else is going on.
5. (opinion only) The only factor that I would expect to change circulation flow during a DHW run would be that of physical properties (density, viscosity etc) on pump performance. IMHO the Samsung controller is a pretty blunt instrument (much as I love it) and my search for sophisticated DHW algorithms has to date eluded me.
6. If anyone can explain what FSV #4053 does, I’ll offer a small cash prize. Nick K doesn’t know, and changing it seems to make b* all difference to anything.
Sarah

[johnfresh (John Freshwater)]

Hi Sarah

Robert Kerr at Samsung when I asked about it said it’s an equation factor that works with t1 and t2

Which I’m sure you will agree means absolutely bugger all.

I forgot to ask him what the equation factor was is it a multiplier or something else

Love to know as far as I can see as my emitters and also my hot water cycle drop below a 5 degree delta t my pwm pump is at flat out all the time anyway. Maybe due to my flow rate is about right for heat output which is more luck than judgement

John

[johnfresh (John Freshwater)]

That should have said do not drop below delta t of 5 therefore the pump doesnt need to slow down to allow more loss of heat resulting in bringing back to 5

[johnfresh (John Freshwater)]

Hi Sarah

See below this is what Robert sent me a week or so ago there was a drawing with it but that does not have pasted with the text

Tried forwarding it to you but bounced back

John

Hi John,

It is used as part of the equation when determining the PWM speed against the DeltaT.

Best regards

[johnfresh (John Freshwater)]

Try the attached

[Robert.Wall]

@johnfresh

there was a drawing with it but that does not have pasted with the text

You might need to save the drawing locally, then reattach it to your post (drag & drop).

[johnfresh (John Freshwater)]

Its there now

[SarahH (Sarah Hanson)]

Many thanks for that info, John, it’s really helpful.

It explains why I couldn’t see any relationship - I’d been assuming proportional only control, when it’s clearly (proportional + differential) control. Subtle.

A little (50 year old) knowledge is a dangerous thing…

Sarah

[johnfresh (John Freshwater)]

No worries

It just shows if your emitters are sized correctly and you are always open loop then a pwm pump is not really needed as long as your flow and heat emmittance are right you should maintain a reasonable delta t

Although the Grundfos PWM UPM4XL isn’t any more expensive than some of the other non pwm pumps

John

[johnfresh (John Freshwater)]

Hi Sarah

Robert Keer is back from his holiday and sent this which ckears it up

Hi John,

The PWM control logic during heating (doesn’t apply to DHW, as that is fixed to 5K) is to have a:

• ∆T of 5K when the supply is between 25~45°C

• ∆T of 8K when the supply is between 45~50°C

• ∆T of 10K when the supply is between >50°C

This is only when the system is balanced at the optimal flow rate for the heat pump installed.

5kw 14.5l/min

8kw 26l/min

12kw 35l/min

14KW 40l/min

16kw 46l/min

The logic is activated in the FSV’s for an inverter pump (factory default) and starts evaluating 5 minutes after safety start, but after 20 minutes of an operating system.

Regards

John

[glyn.hudson]

@johnfresh

Hi Glyn

Where did you get the control cable from for the grundfos circulator
I have found a place but they want 16 quid for delivery

Sorry for the late reply. I got my Grundfos pump from Midsummer Energy. It included the PWM cable. Be sure to check the model carefully, not all Grundfos pumps support PWM.

@johnfresh

Bear in mind PWM modulation is only active in heating mode with flow temps exceeding 45C.

That’s not correct, on my Gen6 PWM will modulate the pump to maintain DT at any flow temperature e.g 30C

Here’s a link to view my data: Emoncms - app view dashboard

@johnfresh

The PWM control logic during heating (doesn’t apply to DHW, as that is fixed to 5K) is to have a:

I don’t think this is true, I’ve observed PWM being active during DHW, it seems to modulate down to 17 L/min, without PWM my pump will run at 22 L/min.

---

However, I did need to update my firmware to get PWM to work. The dataplate on my HP says it was manufactured in 2021:

Samsung MIM-C02N S-NET Pro Dongle

No, apparently the UK Samsung technical don’t get to see any FW change logs themselves I have a AE050RXYDEG-EU heat pump. All I know is that updating my indoor controller MIME03CN (DB91-02103B) to 220614 seem to fix my pump PWM. It wasn’t modulating at all before, now it’s modulating correctly My Main Micom (DB91-02091B) is running firmware 190704, the latest firmware for this is 221130. However, without a changelog and because my HP is working well, I’m a bit hes…

For the first year I ran my HP without PWM, I’ve just come to the end of my 2nd year with the HP, this time with PWM enabled. This year I go a SCOP of 4.45 compared to 4.19 in the first year. I think PWM has helped with this 0.26 increase in SCOP, although it’s hard to say for sure.

[johnfresh (John Freshwater)]

Glyn

Not sure if you see my last reply to Sarah from Robert Kerr at Samsung see below

Hi John,

The PWM control logic during heating (doesn’t apply to DHW, as that is fixed to 5K) is to have a:

• ∆T of 5K when the supply is between 25~45°C

• ∆T of 8K when the supply is between 45~50°C

• ∆T of 10K when the supply is between >50°C

This is only when the system is balanced at the optimal flow rate for the heat pump installed.

5kw 14.5l/min

8kw 26l/min

12kw 35l/min

14KW 40l/min

16kw 46l/min

The logic is activated in the FSV’s for an inverter pump (factory default) and starts evaluating 5 minutes after safety start, but after 20 minutes of an operating system.

So this would be correct for your set up