LG Therma V Monobloc CH14 flow error

[ProDave]

I can't be of much help.  Clearly newer versions of the LG heat pumps are very different to my old one that started the thread.  Mine cannot adjust the flow rate in the software and cannot even read what it actually is, and if the flow rate is not sufficient (simple flow switch) it trips with the CH14 error requiring a power cycle to reset it.

[Michael_S]

48 minutes ago, ProDave said:

I can't be of much help.  Clearly newer versions of the LG heat pumps are very different to my old one that started the thread.  Mine cannot adjust the flow rate in the software and cannot even read what it actually is, and if the flow rate is not sufficient (simple flow switch) it trips with the CH14 error requiring a power cycle to reset it.

I have this controller but for example enter time set with a short press of the settings button - a 3s press takes me into the configuration settings.  Do you have this controller?  How can I just make it turn on and run - the on button and choosing Temp mode or AI mode does make it run but it then just goes to off after about an hour, pressing the on button makes it go again.  no error messages.  Don't think I have set p any reservations although when I go into the weekly reservations menu I see some odd times with the hours and minutes outside of the 0-24 and 0-60 range.

 

[ReedRichards]

@Michael_S, your controller is either very new or very old; it looks nothing like the one I have (which is the same as the one in the picture on the previous page).

[ProDave]

8 hours ago, Michael_S said:

I have this controller but for example enter time set with a short press of the settings button - a 3s press takes me into the configuration settings.  Do you have this controller?  How can I just make it turn on and run - the on button and choosing Temp mode or AI mode does make it run but it then just goes to off after about an hour, pressing the on button makes it go again.  no error messages.  Don't think I have set p any reservations although when I go into the weekly reservations menu I see some odd times with the hours and minutes outside of the 0-24 and 0-60 range.

 

That is the controller I have.  I very early on worked out you had to get into the mindset of whoever programmed it and there are many things I don't understand about it.  I regard it as somewhere to set up the parameters and somewhere to check on it's status.  I don't use it for control.

 

Instead mine is set up to use a "room thermostat" to control the heating.  That is a jumper option on the control board.  Then I have a conventional boiler time clock and room thermostats for the UFH that between them generate the "room thermostat" signal for the heat pump.

 

I chose this method because everybody understands a boiler time clock.  It gives you the normal timed options, 1 hour or 2 hour boost, program advance etc.

[Michael_S]

2 hours ago, ProDave said:

That is the controller I have.  I very early on worked out you had to get into the mindset of whoever programmed it and there are many things I don't understand about it.  I regard it as somewhere to set up the parameters and somewhere to check on it's status.  I don't use it for control.

 

Instead mine is set up to use a "room thermostat" to control the heating.  That is a jumper option on the control board.  Then I have a conventional boiler time clock and room thermostats for the UFH that between them generate the "room thermostat" signal for the heat pump.

 

I chose this method because everybody understands a boiler time clock.  It gives you the normal timed options, 1 hour or 2 hour boost, program advance etc.

Thanks.  Part of me wonders if I have the right controller for the heat pump (12kW HM121M U32)

 

When you say you use thermostat control, I can see how you would feed the heat pump with a temp sensor (our heat pump has a netatmo receiver unit inside but didn't come with the sender unit so I have set the dip switches to ignore it) but is there any way to just give it a simple 'on/off' signal which you could then control with whatever home automation software you had available?  You can't simply control the power supply as it seems to lose all settings and start in the 'off' condition - plus probably not that good for it too simply power off in the middle of operation.

 

Thanks

[Michael_S]

OK.  It is turning off every hour, on the hour, regardless of how long it has been running at that point....

[ProDave]

26 minutes ago, Michael_S said:

OK.  It is turning off every hour, on the hour, regardless of how long it has been running at that point....

Is this space heating or hot water?

[Michael_S]

Space heating only.  The aux heater is disconnected and turned off via dip switches

 

Thinking I will remove the Netatmo receiver even though it is not supposed to be doing anything.

 

With your control method, what sort of signal are you sending to the heat pump and how is it connected - is it simply an on/off signal or is it a temperature signal?  Mains voltage or low voltage signal?  Thanks

Edited October 28 by Michael_S

[ProDave]

The thermostat input is I think a 240V switched contact.  My older one really is simple, heat demand or not demand that is it.  It does in theory have weather compensation. I tried that once with the result it switched to cooling mode.  Clearly I had something wrong but couldn't figure out what so I abandoned that idea and have not tried again.

 

What mine does and how seems a long way from what and how the newer ones operate.

[Michael_S]

4 hours ago, ProDave said:

The thermostat input is I think a 240V switched contact.  My older one really is simple, heat demand or not demand that is it.  It does in theory have weather compensation. I tried that once with the result it switched to cooling mode.  Clearly I had something wrong but couldn't figure out what so I abandoned that idea and have not tried again.

 

What mine does and how seems a long way from what and how the newer ones operate.

Thanks again - you don't happen to know how the on/off thermostat is connected inside the outdoor unit do you?  Do you control it via a wired connection or use a remote wifi switch?

[ProDave]

All hard wired.  There are a lot of different control signals in and out of the outside unit so I ran a 10 core cable in addition to power to connect these and leave some spares.

[ReedRichards]

23 hours ago, ProDave said:

That is the controller I have. 

 

21 hours ago, Michael_S said:

Part of me wonders if I have the right controller for the heat pump (12kW HM121M U32)

 

I'm now on my second LG Therma V, 12 KW U32.  According to my "Owners and Installation Manual" 

H designates an Air to Water Heat Pump

M designates Monobloc

12 is the heating capacity (so 12 kW)

1 indicates 220-240 V ~50 Hz

M indicates Leaving Water Temperature Middle Combination (which is the only option given for this designator)

U3 indicates a UN3 Chassis (alternative is UN4)

2 indicates the series number

 

So you have a Series 2 heat pump.  I can't tell you if that means you have the right controller or if your heat pump would work with the newer model of controller.

 

[Michael_S]

Thanks both.

 

Think I have the right controller and have managed to fix the switching off issue but finding out how to clear all the 'reservations'

 

Am now running on AI mode using the WT but it is currently so mild I am not sure if it is really working or not, I am just getting some really short cycles - say 5 mins every 20 mins.

 

Does anyone use the AI/weather comp mode? What does it do beyond the high temp setting, say the settings are -10 +50 and +15, +25, what happens if the air temp is 16C+  does it automatically power off or will it continue at 25C whatever the air temp?!

 

Finally still on the question of thermostat control - if I connect a wifi switch to the thermostat and get it to send a mains live output to the control terminal when I want the unit to come on and no output when I want it off, will this work to control the unit (if I set the correct dip switch?

[ReedRichards]

20 hours ago, Michael_S said:

Does anyone use the AI/weather comp mode? What does it do beyond the high temp setting, say the settings are -10 +50 and +15, +25, what happens if the air temp is 16C+

 

In the case of my new Therma V, which is about a year old and, I think, a Series 4, it switches off.  This makes sense if it comes on to do cooling at an even higher outside temperature but since the cooling feature is turned off on my heat pump I regard this as a bug.  However I think my old Therma V, which must have been series 3, would have maintained the LWT at the minimum figure (25 C in your case) if the air temperature was above the maximum.

 

So unless @ProDavecan tell you, you will need to answer your question by experiment.  

[JohnMo]

20 hours ago, Michael_S said:

what happens if the air temp is 16C+  does it automatically power off or will it continue at 25C whatever the air temp?!

Mine (not the same make) and every other manual I have read (loads), once temp goes to 16 and above it just stays on the same flow temp. Your 25 degs is probably the lowest set point you can go.

 

21 hours ago, Michael_S said:

wifi switch to the thermostat and get it to send a mains live output to the control terminal when I want the unit to come on and no output when I want it off, will this work to control the unit (if I set the correct dip switch

I would really read your manual on this subject because get this wrong it could be very expensive. Most heat pumps look for zero volt contacts.

 

You should have a setting or mode within the unit thermostat controller to do this function itself. Sort of a hybrid thermostat and WC control mode.

[Michael_S]

On 30/10/2024 at 07:52, JohnMo said:

Mine (not the same make) and every other manual I have read (loads), once temp goes to 16 and above it just stays on the same flow temp. Your 25 degs is probably the lowest set point you can go.

 

I would really read your manual on this subject because get this wrong it could be very expensive. Most heat pumps look for zero volt contacts.

 

You should have a setting or mode within the unit thermostat controller to do this function itself. Sort of a hybrid thermostat and WC control mode.

This is the install manual, page 41 and 42 seems to me to imply that the feed to the thermostat is 230v and it expects a 230v live return on the call for heat.  Anyone else read it the same way or have the same model with a thermostat to confirm?  Thanks

 

https://gscs-b2c.lge.com/downloadFile?fileId=EoU8EjdDipG6CZuc7jLw

[ReedRichards]

I have a Drayton Wiser system with two wireless room thermostats and a control box which is wired in to the heat pump.  I got this before I got my heat pump and it controlled my old oil boiler.  I'm sure that oil boiler used a switched live and I have no reason to believe that the heat pump was rewired differently.

[sharpener]

@JohnMo's advice upthread was very sound as many HPs require voltage-free contacts (and I have had to add a relay to achieve this when converting from an oil boiler).

 

So @Michael_S is lucky to have one which does not.

[ReedRichards]

Switching 240 V seems like something out of the dark ages but it was the norm for boilers.  Just looking elsewhere, it seems a single channel Hive uses voltage free switching but a dual channel Hive (heating and hot water) switches 240 V.  

[Michael_S]

On 06/11/2024 at 10:08, sharpener said:

@JohnMo's advice upthread was very sound as many HPs require voltage-free contacts (and I have had to add a relay to achieve this when converting from an oil boiler).

 

So @Michael_S is lucky to have one which does not.

Thanks, I am lucky enough to have lying around two different wifi relay/switches, one of which powers and switches on or off a 240v circuit, the other a low/volt free circuit.  Just need to use the correct one...

 

Aroidful Mini WiFi Smart Light Switch DIY Breaker Module, WiFi Smart Relay Switch Controlled by Smart Life/Tuya App, Compatible with Alexa Echo and Google Home, Support 1 Way or 2 Way 100V-240V 16A : Amazon.co.uk: DIY & Tools

 

DieseRC 1 Channel WIFI Smart Switch, DC 5V 12V 24V 36V passive output Relay Module Ewelink APP WIFI Control Compatible with Alexa/Google Home, Inching/Self-locking Switch : Amazon.co.uk: DIY & Tools

[Michael_S]

Annoying, have the dreaded CH14 today. 

 

As above I have a second pump that runs full time and the flow rate on my heat meter seems to be what it always was so I guess that points to a problem with the flow sensor rather than a real flow obstruction?

 

Any other thoughts?

[Michael_S]

WE have the sensor unit with 4 screws that seems to be common with a tumble dryer - seems to cost a minimum of 115

 

A bit of experimentation - the 'paddle' needs to be down (no flow) when the unit boots and up (flow) once the pump comes on - not sure if I can do something clever as a one off during start up or whether it will also check there is no flow whenever the pump is off - the current error state is that it appears to think it is up (flow) all the time.