@iantelescope

Electric motors, by their very construction and operation, present a predominantly inductive load rather than a capacitive one, so I find the French Samsung Engineer's comment rather strange. He may have been confusing the starting current (normally 3 times normal running) as being caused by capacitive inrush.

Arcing at relay contacts normally occurs when the contacts are opening, not closing, so is more likely to happen when the motor is switched off.

While I cannot state for certain, I would hope that the Samsung Design Engineers would have selected relays of adequate capacity to perform their assigned duties in a reliable and consistent manner. So provided that the installed water pump motors do not exceed the maximum specified operating limits set by Samsung, I would not expect that switching the motors on and off via a relay should cause any problems.

I suggest that you check the specification of the relays installed and compare that data with the specified operating limits set by Samsung.

@derek-m 

Inrush currents and Relays on Samsung -Grundfos Heat Pumps.

The Grundfos Motors , unusually for motors , present a Capacitive Load to the AC  mains:

At the bottom of the Inrush Warning page , note the further  Warning :

" if you use a Relay to switch the Power supply of the Pump, you risk excessive wear on the Relay Contacts......."

Grunfos then provide various remedial fixes for relay burnout , the Relays will still ,however be subject to life span limiting sparking.

Reduced  Relay switching will extend the life of the Relays.

Given that my Samsung can optionally keep the Mains AC Voltage to the Motor permanently ON No Relay Wear would occur.

The PWM Input to the Grundfos can be switched OFF by applying a PWM signal at 85% to 100% of the PWM Period.

The PWM can also control the output Delta_t using the Sensors at the Heat Pump output Ports.

GRUNDFOS motor Status:

Grundfos motors can optionally return the Motor Status.

  Samsung Does NOT, however,  use the Returned Status.

Should the Motor fail the user will have NO indication of  failure nor the source of the failure.

My MOTOR is failing when driven by the Samsung PWM as source.

ARDUINO Sourced PWM Signal:

On my Samsung, when the PWM is sourced by an Arduino,  the Returned Status shows the Motor power in Watts as a PWM Signal. 

Samsung's prime motive in Heat Pump  Design  was cost and availability !

Motors switched  by Relays are cheaper, and more readily available ,  than Solid state devices driving PWM controlled motors!

@derek-m @iantelescope With the greatest respect folks, we are getting bogged down with this relay issue 🙂

Samsung control boards do not have any relays installed in them for switching electric motors. As I have stated in previous posts the Samsung board has surface mounted components which are capable of supplying up to 100w of power to drive an electric pump. Any pump which has a power consumption greater than 100w requires a relay to switch it on and off. The only time you have arcing is for large electric machines which we do not have in this case, we are talking typically 70w at 240v so can we please keep things in perspective?

@iantelescope if your Grundfoss pump draws less than 100w then you do not need a relay and you certainly do not need a relay for the pulse control

Regards

@technogeek & @derek-m & @Mars

PWM STATUS RETURNS:

This is the Status Returned from the Primary Grundfos motor when driven by an Arduino:

The Returned PWM Signal indicates a Grundfos motor driving at 21% below maximum power.

The Arduino is working , the Grundfos motor displays success, but the Samsung Does NOT provide the correct PWM Source to drive the Grundfos motor.

My Heat Pump ONLY Starts and Stops  when the Samsung PCB Switches the Motors On and OFF using B7 Neutral and B8 Live as described in the Installation Manual for Case 2.

My Heat Pump generates the correct Delta_t  ONLY when sourced from my Arduino . The Continuous Mains Motor  connection , B1 Neutral and B6 Live causes the Heat Pump to issue E9112 Errors,  intermittently.

In summary , my Heat Pump ONLY Works with Case 1 AND Case 2 , as described in the Installation Manual,  simultaneously enabled.

The Grundfos Motors supply my Samsung with the correct Status when driven by an Arduino.

My Samsung ignores the Status indication, in NOT USING the Black  PWM Return Wire.

My Samsung is failing and I have , therefore , No indication of the Fact of the Failure NOR of the Cause of the Failure.

@derek-m 

BS7593: Addendum 2019

Because of this :

I get this, in my Pipe water Supply *

My Heat Pump, this year , every year , totally fails BS7593 Addendum 2019:

Last year I spent £600 having BOTH Water Circuits Cleaned!

Zone Valve STATUS:

My Samsung-Telford Built Heat Pump is fitted with Honeywell V4043H Motorised Zone Valves.

The V4043H Valves have NO Feedback giving indication of Motorised Zone Valve Jamming , Failure or Timing issues.

Why NO Feedback from the Zone Valves?

* Phase Contrast Microscope

@iantelescope

I would suggest that you check the Chemistry of the water within your system.

Started reading some of the 43 pages of this thread, all I can see

1. Lots of odd stuff going on

2. Fixing issues in kit that should just be deleted,such as secondary pumps.

3. Lots of going round in circles.

4. 3rd party controls achieving what?

My suggestion is less time writing stuff on here and more time 

A. Getting a basic simple system design together, ask for a review, make appropriate changes on paper first.

B. Implement that design

This method has been tried, but failed. You may have greater success.

Unfortunately Ian is reluctant to make any physical changes to his system.

The only remaining method has been to try to guide Ian through the various ways in which his system could possibly be optimised.

I will bow out, way too many posts to keep track on what has or hasn't been done to date

@derek-m 

"Checking the chemistry of my pipe water "

Last year I spent a further £600 having the water in both Water circuits replaced after the first indication of the Black Ink Water problem.

I asked the Flushing engineer to perform the BS7593 :2019 test only to be rebuffed with the comment that " Water replacement trumps .......BS7593:2019, it is not needed"

I was later attacked by my former "installer" with the claim that "They had performed the Water tests , and pipe cleaning as shown on the Installation documentation".

Attacked, here, means a pair of "engineers "  Shouting and trying to intimidate me.

The visiting NIC Engineer then attacked my "installer" with the comment that the installation documentation was indeed nonsense.

I have NO Confidence in my "installer" , the NIC ,  SAMSUNG and TELFORD.

The last straw was an attack by the NIC Engineer , who had the audacity to say that "I , the user, Must not , in any circumstances, change the settings of my "installer".

This despite the obvious incompetence of my "installer".

Little wonder that I am unwilling to contemplate a complete system "rebuild & simplification " .

I am in despair with Heat Pumps!

@derek-m 

Fail BS7593:2019

Having spent >£14000 on my Samsung-Telford Heat Pump, after two years I still have a system filled with BLACK INK instead of water .

My System , like many , if not most , would fail BS7593:2019 for both water clarity and water Ph!

My "installer" ticked the box indicating that my water supply was cleaned in the "installation". Untrue, according to the NIC!

The NIC  MCS say that "You are not going to like this BUT Nothing can now, unfortunately be done".

Little wonder I have NO Confidence in this Industry !!

@derek-m 

"Unfortunately Ian is reluctant to make any physical changes to his system."

Unfortunately, Samsung-Dalliam advised , within two months of the Heat-Pump Installation that " a Buffer tank was required ".

Telford the actual system builder added the comment "that THEY ALWAYS Installed a 50l Buffer tank " .........Always!!

My "short cycling" was not caused by the absence of a Buffer tank!!

The total failure of the "manufacturer Samsung " , the "builder" Telford , and my "installer" to accept any responsibility has destroyed any and all Confidence.

The NIC MCS has further destroyed my confidence !!

I agree " I would like to replace my system with a greatly simplified System , But who is competent and  trustworthy ? "

After Two years of buck passing,and  finger pointing incompetence   displayed by my "installer" ,SAMSUNG-Dallium , TELFORD and a host of others                 .....who is trustworthy?