Posted by: @iantelescope

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My system would appear to be one of many !!

Some things were done, and in some cases are still being done, in heat pump installations that are more for installer convenience and backside covering than for performance.  Slowly they are being exposed as bad, but its taking a long time.  @mars has written a book on it!

@jamespa 

Hi @jamespa,

If trying to save money , why is my Samsung with Two Pulse width Modulated motors when the motors without speed control coat half of the price of a Pulse Width modulated version?

Similarly , why fit a £150 EAC 12-12 Kw Heat exchanger if it is not required?

Finally , why install Two motor, Two Water expansion vessels , Two PRV's when only one is needed?

Also , why is my heat pump configured for Pulse width Modulated Motors when simple ON OFF switched versions are actually used?

None of this makes any sense!

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Samsung-Homely installation revelations:

Secondary motor RELAY:

Homely provide a Relay to allow  the Secondary, Radiator motor,  to be driven from the Additional  Fixed speed output , B7 and B8 on the Samsung control board. Two motors!

This is identical to the arrangement used by Samsung themselves when driving TWO Motors. see Samsung installation instructions .

Samsung/Homely expect a  Heat Pump to have a Primary and secondary water loop system, providing a relay to drive TWO Motors , Primary and secondary !

Samsung Variable speed drives:

The SAmsung Heat Pumps fitted with Variable speed motors do Not require system modification when installing Samsung-Homely!

Where is the PWM output plug driving the Second motor?

Homely disables Weather compensation:

Homely give explicit instructions about stopping Weather Compensation, Water Law , WL,WC  by using Field bits 2091 option 0 .

Confusion reigns !

I see no confusion. 

Homely applies its own weather compensation hence why Samsung's must be disabled.  As I said earlier homely is not a thermostat it's a flow temperature controller.

It's not Samsung that recommend a complicated system with more components, it's Joule and other installers.

Both Samsung and homely of course recognise that there are a variety of system arrangements and so give some instructions on how to support them.  They do this to make their systems attractive to a wide audience.

Pwm pumps make it easy for installers to set up the system.  As I explained earlier it's arguably preferable to have a fixed pump speed with radiators, because the WC curve then more closely tracks the ideal curve.

In summary the complexity and extra cost is due to installers/system designers not the equipment manufacturers.  They are not trying to save money, they are trying to maximise profit and maintain minimise call outs. It's a sellers market so they can afford to do this.

As usual you have to look at the selfish motivations of each party separately to rationalise what is going on.  

@jamespa 

Hi James,

Sorry to sound , as I feel , angry, frustrated  with myself , with  Half educated "installers", with that renowned  "Charity ",  the MCS , so rightly praised for it's "Charitable Educational functions".

Sorry , this is, and they are, altogether ,  too much !

Posted by: @iantelescope

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Sorry to sound , as I feel , angry, frustrated  with myself , with  Half educated "installers", with that renowned  "Charity ",  the MCS , so rightly praised for it's "Charitable Educational functions".

You aren't alone in feeing frustrated, it's a frustrating industry.  Sadly, so is much of the construction industry!  There are good guys in the construction industry, but they seem to be in the minority.

Good luck with the works today!

@jamespa 

 My Plumber has just left , having  assessed  the work involved in converting my Samsung Heat Pump to a single Loop System .

Here is a summary of his findings:

1) Repositioning the Buffer Tank:

The Tank could be repositioned forming a "Series connected" tank in the Return pipe to my Heat Pump.

2) Repositioning the Dosing tank:

The Dosing tank would have to be repositioned under my floorboards, in my "cellar" .

I would have to lift the floor boards to access the Dosing pot.

3) Shorting out the Heat Exchanger:

This would not be possible given the current "messy tangle" of pipes .

The Entire piping system would have to be removed , being replaced by a parallel set of pipes connected to both walls.

 A return to a two water loop system would not be possible or affordable.

Given water contamination in the Radiator water circuit it would not be advisable to remove the Heat Exchanger.

4) Water contamination emminating from the only remaining old Radiator could be removed by replacing the Imperial  Radiator with a specially adapted metric version.

He will quote for the replacement of the old Radiator.

Even without removing the Heat Exchanger along with the entire pieing system ,  the costs may well be  large.

I'm really sorry to hear that.  Obviously your plumber decided he didn't want to do the job after all and really does want to persuade you to rip the lot out and replace it with a gas boiler.  He will make the rest of his career on this one, telling people not to touch heat pumps because of what he saw in your installation.

As a matter of interest what is the 'dosing pot'?

My only remaining suggestion is the one I made a couple of weeks ago, ie draw up a scope of work (which is essentially done) and put it out to all the plumbers within say 15 miles.

@jamespa I think a dosing pot is an inline receptacle that is used to add ‘additives’ to the water isn’t it? I suppose isolating valves are employed before opening the pot to allow the additive to be placed in a ‘hopper’ then sealed again, valves reopened allowing mixing of additives. Of course I may be talking out of the wrong orifice altogether! Regards, Toodles.

@toodles

Well I accept that is a logical interpretation however why have one? 

My heating system doesn't and neither does any other heating system I have seen (which I admit is only a dozen or so).  If I need to add chemicals I drain some water, open a radiator, put the chemicals in, seal up the radiator, refill, job done.  About 30 mins in total and no 'dosing pot' required!

Posted by: @jamespa

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FSV2093 is still a bit of a mystery.  If using both internal temp sensor and WC I have the impression the default value (4) is the one to choose as this sniffs the LWT from time to time and thus gives the unit the information it needs to decide whether to turn back on because LWT is low.  But I cant actually work out what the other options are for.  Do you have any insight into this? 

I think options 1-4 operate in identical ways for FSV 2091, 2092 and 2093

Option 1 - compressor can be turned off only by the stat. If LWT rises above target, but stat calling for heat, then the LWT continues to rise to a new equilibrium

Option 2 (Water Pump 1) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run for 1 minute and then turn off

Option 3 (Water Pump 2) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run continuously.

Option 4 (Water Pump 3) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run for 3 mins and off for 7 mins, on for 3 mins etc

With options 2-4, if the stat is still calling for heat, the compressor will restart as soon as the LWT falls 1-2 degC below target. What difference the water pump on/off timing makes is a mystery to me. On my system, once the compressor cycles off because of the LWT being above target (usually mild weather and LWT below 33C) the compressor will then continue to cycle on and off 7-8 times an hour, which is not good, but it also means that options 2, 3 or 4 make no difference to this behaviour. I have seen the same thing reported by other Samsung owners and it can be seen on heatpumpmonitor.org too. When I had a 50 L buffer it cycled even worse!!!

@jamespa Fairy Nuff James! I suppose the same task might be accomplished via the ManaClean ‘Pot’ but… I’m not nor ever have been a plumber! Toodles.

Posted by: @mike-h

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Posted by: @jamespa

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FSV2093 is still a bit of a mystery.  If using both internal temp sensor and WC I have the impression the default value (4) is the one to choose as this sniffs the LWT from time to time and thus gives the unit the information it needs to decide whether to turn back on because LWT is low.  But I cant actually work out what the other options are for.  Do you have any insight into this? 

I think options 1-4 operate in identical ways for FSV 2091, 2092 and 2093

Option 1 - compressor can be turned off only by the stat. If LWT rises above target, but stat calling for heat, then the LWT continues to rise to a new equilibrium

Option 2 (Water Pump 1) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run for 1 minute and then turn off

Option 3 (Water Pump 2) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run continuously.

Option 4 (Water Pump 3) The compressor can be turned off by the stat or by the LWT rising above target. The water pump will run for 3 mins and off for 7 mins, on for 3 mins etc

With options 2-4, if the stat is still calling for heat, the compressor will restart as soon as the LWT falls 1-2 degC below target. What difference the water pump on/off timing makes is a mystery to me. On my system, once the compressor cycles off because of the LWT being above target (usually mild weather and LWT below 33C) the compressor will then continue to cycle on and off 7-8 times an hour, which is not good, but it also means that options 2, 3 or 4 make no difference to this behaviour. I have seen the same thing reported by other Samsung owners and it can be seen on heatpumpmonitor.org too. When I had a 50 L buffer it cycled even worse!!!

I assume that option 4 is to allow the heat pump to 'sniff' the temperature of the heating water from time to time without running the pump constantly.  Option 3 the pump runs constantly so the pump knows the heating water temp.  Option 2 the heat pump doesn't actually know the heating water temp, which may or may not matter.  Thats what I assume anyway, I may be wrong!