LG Therma V mono block Air Source Heat Pump

[joth]

53 minutes ago, Arvyd said:

the best algorithm for heat pump is if it working all the time without shut downs

I'm no heat pump expert, but, my understanding is over a short period you are correct (avoid short cycling), but over the long period you do want it to turn off as much as possible during each day

 

If it keeps stopping and starting every minute it will not reach maximum efficiency. And it should be set to the lowest water temperature that works.  But beyond those constraints, you want it to turn off for as many hours as possible each day to save power overall , if this makes sense?

 

58 minutes ago, Arvyd said:

I am lucky ? owner of Therma v R32 9kw. I sent this heat pump from Italy and installed it at my self

Congratulations on this. How did you go about buying it from Italy? On internet, and what price?

 

Thank you and welcome!

 

[Arvyd]

 I use room thermostat to, but seems its not help. I think its possible that heat pump will be

working more effective(i tell about power consuption) if its working at minimum power but for a long time then if at full power  short time. I think thats possible with installers options, but I didnt understood  how, til now.

I bougt it on Climaway site for 3100 euro, but I think that its not actual for You, becouse I saw similar price in UK. Room thermostat bought on Ebay, HWT thermostat from China - for reasonable price. Pump connected to grid with soonof wifi module, its counting energy consuption.

Edited December 5, 2019 by Arvyd

[SteamyTea]

9 hours ago, ProDave said:

To enable that you have to flick one of the DIP switches on the control board

Any pictures, or a reference to the manual?

[ProDave]

15 minutes ago, SteamyTea said:

Any pictures, or a reference to the manual?

I could post a link to the manual for mine, but it would be more helpful if @Arvyd posted a link to the manual for his which is bound to be different.

 

In my case the pump should not run all the time.  The pump is integral to the heat pump (plus I suplimented an external one as well) and only turns on when the HP is working.

 

It should not make much difference to total energy usage how the heat pump is timed.  In our low energy house I have it timed to be on in the day and off at night (for a silent night) when it is on in the day it is under the control of the room thermostats.  The temperature does not drop much overnight so if it were left on it would just cycle a couple of times to keep the temperature up, which would then give it less work to do in the morning, so I doubt it would cost an more.

[SteamyTea]

2 minutes ago, ProDave said:

I could post a link to the manual for mine, but it would be more helpful if @Arvyd posted a link to the manual for his which is bound to be different.

 

Good point.

[Arvyd]

Here is the link to the manual of r32 https://www.manualslib.com/manual/1511067/Lg-Therma-V-Series.html?page=21#manual

 

Here are jumpers and their functions and places (realy 13 page will be oposite- upside is dowsnide.

 Its not difficult to find the jumpers, just need dismount right cover of monoblock, then release block of connectors. The jumpers are On the board deeper.

LG Therma V R32 Monobloc - Quick Install Guide 2019 (1) (1).pdf

[ProDave]

There are some differences to mine, the controller is completely different.

 

To enable the thermostat input, switch  DIP switch 2 - 8 UP

 

The thermostat input is on terminal block 3.  Input L2 on terminal 30 is the heating switched L input and L on terminal 27 is the L out to the thermostat.  N on terminal 28 is neutral if your thermostat / controller needs it.

[Arvyd]

Some pictures from my researches ?

The best power consumption/working continuing.

[ProDave]

Re visiting this old thread, because after working fine for well over a year, in the last week, my ASHP has thrown up 3 spurious CH14 low flow errors. the common theme once more being this happened over night with no demand, just as they did before, so the unit refuses to start in the morning without the fault being reset.

 

So I had another look and think I have a hunch what the issue is.

 

In the summer, I connected a wire to the "cooling" thermostat input to test it's cooling function.  That is unused at the moment, but the wire is still connected.

 

Now I previously had an issue with the heating thermostat input being over sensitive, and I cured that by fitting a pull down resistor and a snubber.  But I never thought to do the same when i connected the cooling input.  It is reasonable to assume they both use the same input configuration, and either will trigger the ASHP to start so it's reasonable both will trigger the same start up checks for flow rate with the same fault mode if a short spurious input is detected.

 

So today I fitted the same snubber and pull down resistor to the cooling thermostat input.  I will now see if that has cured it's latest bout of flow errors or not.

[Tigaz52]

Hello,

I own a therma v monoblock 12kw 1-ph from 2015.

It is running directly to underfloor heating with three indoor thermostats. The thermostats are wired so at any case one of them is open.

Since now everything seems normal except sometimes a ch14 error code.

But I have managed to remove it by opening the filter. (The filter was clean).

Yesterday the ch14 appeared again.

I've tried cleaning the filter, bypass the underfloor heating, knock the flow sensor but the error still come back.

Please for any suggestions.

Also I would appreciate the service manual for the model.

Thanks in advance

[ProDave]

I strongly suspect your problem is the same as mine, a spurious and very short pulse detected by the HP thinking it has a heat demand and turning the pump on for a fraction of a second but not long enough for the flow meter to operate hence it trips with the CH14 error.

 

I "fixed" mine by filtering the thermostat input with a 100K wire wound resistor from input to N and in parallel with that a snubber consisting of a capacitor and resistor in series.  Is that something you would feel confident fitting yourself? or do you know someone that would fit it for you?

 

I am sending you the service manual. Don't get too excited there is not much in it,.

 

 

[ProDave]

I come back yet again as I am still having spurious CH14 errors (low flow rate)  As before they happen when the unit is idle.  Heating is off now and for the last 3 days or so it has not even come on to heat DHW as the solar PV has been doing that all by itself.  Yet I notices yesterday afternoon it had once more, while idle, thrown up a CH14 error.

 

I have speculated in the past that I believe it to be a very short spurious heat demand being sensed by an over sensitive input and then processed by some badly thought out software.  My previous attempt to fix this has been a pull down resistor and a snubber on the thermostat input.  It seemed to work at first but now the problem is back, I don't know why.

 

So this morning I have implemented what I think is a more robust fix.

 

The input from the thermostat no longer goes directly to the thermostat input terminal. Instead it is used to energise a small relay that I have fitted inside the ASHP.

 

And now I use a changeover contact on that relay to energise the heat pump.  The relay common connects to the heat pump thermostat input terminal. The relay NO connects to L so when the relay energises the heat pump gets the call for heat demand as if it came straight from a room thermostat.  But crucially now, the relays NC contact is connected to N. So when there is no call for heat, the input is not just floating, with a long length of wire attached, but is clamped down to N so there really should be no chance of any induced spikes that I think have been the cause of the problem.

 

I now go into a "wait and see" period to find out if this has finally nailed it.  If not, I am out of ideas.

[Diogo Gomes]

Hi!

 

I too have a LG Therma V from 2016. It has been plagued all it's life with CH 14 error.

 

During the warranty period the control panel was replaced and things lasted couple of years.

 

Then the error got back each year after summer. Pressure drop I was told, so I fitted a self regulating valve to top the pressure in the circuit.
 

Early this year the DHW stopped working, gives me the CH 14 but the UFH keeps going (set point at 30ºC) so I switched off DHW (using my tank internal heater)

Until this weekend where the CH 14 became omnipresent. Even if I reset (power-off-power-on) the error is tripped in less then 30seconds...

I've run out of clues on whats going on, the circuit is fully pressurised at 2.5bar. 

[ProDave]

I don't think there is a pressure sensor. I have ran mine as low as 0.5 bar and that is not the cause for the CH14 error.

 

I was going to come back to this thread anyway, as my latest relay mod has not cured the problem, the thing had tripped overnight with CH14 so did not come onto heat the DHW this morning.  So it rather blows my noise pickup on the thermostat input theory.

 

I really only have 2 more choices.  One would be to put the thing on as mains timer to cycle the power off for 5 minutes just before each heating period.  Or the other is yet another relay inside the thing to short out the flow switch whenever the pump is running.

 

I got next to no help when I tried to get help from LG to solve it, so I could not honestly recommend this particular heat pump.  It works fine when it works, but this stupid CH14 error that stops it working from time to time is just stupid.

 

Without fail, mine trips when the unit is off so does not come on when wanted.  I have never known it to trip when asked to run.

[Mo679]

Hello everyone, I read the whole topic and found it  very interesting, I’m owner of a Therma v r32 9kw and I would like to share my experience. I own the heat pump since a year, in winter and heating operation it worked flawless, modulating down to 360wh from my monitoring and down to 1.8kw heat power.

unluckly the heat pump never worked fine in cooling operation, showing a modulation of min. 5.5 kw of heat power,  making it basically on on off heat pump in the summer until the temperatures really go high. 
 

what kind of behavior did you observed in the older r410 model? Does it modulate during cooling operation? Thans s lor

[ProDave]

Hi Mo679

 

I only tried mine in cooling mode once, last summer in a really hot spell.  It was only "rigged up" to test it and not properly engineered.  To do it properly I need to source a couple of fan coil units, add some more plumbing and another motorised valve and change some of the control wiring. So I never got to test how well it modulates.

 

Interesting (and good) that your unit is working reliably. I am particularly interested to know if your setup uses the room thermostat input to the heat pump or not, as that is what appeard to be the source of my problems.

[Mo679]

Hi Dave, I’m not using the room thermostat at the moment, but I used it in the past as the heat pump r32 has one integrated in the remote panel RS3.

it never gave me flow error. I’m just complaining about the poor optimized software and inverter control in cooling operation. 

 

I put up a complex monitoring with a heat meter and flow meter, plus many temp sensor to calculate COP,  and the unit worked silently whole winter.

I made the assistance notice this modulation problem last year and they just joked me around, thins summer I came back with data and numbers, asking for a reply or to see a test setup working, I also asked for a solution I bought a modulating heat pump, i got an on-off one(in summer operation) I had to modify my plumbing, add a 50Lt buffer vessel on the return, just to show that the malfunction was not due to my particular setup.

the head heating ing, than called me admitting, after one year of email and a lot of money and time invested, that the unit “ shows a particular behaviour, not reaching the full modulation potential while cooling”. So he prepared a report to send in Korea. We’ll see net year if they come up with someting.. 

[ProDave]

Thanks.

 

That does mirror my findings that their support was almost non existent and I only "solved" my issues by my own investigation.

 

And I agree the software inside the units has "room for improvement"

 

In my case, my consolation is that I got my unit very cheap indeed so the fact it works, even though it has some issues, makes it okay. But certainly if you paid full price you would expect full support, which seems to be lacking.

 

If we get a heat wave this year and I try the cooling again, I will pay more attention to see how it modulates.  At the moment it only feeds UFH and that was not very effective at cooling the whole house (very little UFH upstairs) so while it cooled downstairs a bit it did nothing to cool the upstairs, hence the need for fan coil units if I am to implement that properly.

[Mo679]

Exactly, but I suspect this issue is relative to just the R32 machines, the older r410 have no report about cooling issue, but it could also be that cooling has not been fully investigated... 

[Mo679]

I just got a mail from lg heating uk. They say in the uk the unit are not used to cool in summer, therefore they have no report of malfunction or bad modulation during cooling operation 

[Mo679]

Hi, could you try out the cooling function of the machine? Thanks for your report, could you tell me what firmware you have on board?

[ProDave]

Re visiting this again.  It has twice thrown a CH14 error again. Once when I left it on for DHW while away for 2 weeks and CH14 was showing when we got back, and once the other morning when the heating did not come on first thing.

 

So the next step in trying to find a work around is I have fitted a din rail timer into my consumer unit. That is set to turn the power off for 15 minutes each morning just before the time it is due to start heating in the morning.

 

That won't stop it throwing a CH14 error but at least it will reset any such error daily first thing in the morning, so if we are away over winter the heating won't just go off and stay off.

 

[philphluter]

Dave, I'm a newbie member about to choose an ASHP / installer to replace our gas boiler / pressurised water system in our 4 year old house.  One quote I have is for an LG Therma V system so your experience and detailed postings are of great interest:

 

I have not heard you mention a buffer tank in your system.  Do you have one?  Doesn't a buffer tank, two pipe or 4 pipe, allow unrestricted flow in the heat pump's water circulation system when no zones are calling?

[ProDave]

Yes a buffer tank would make it easier / more dependable to achieve the flow rates.  I don't have one.

 

If you are paying for a system to be supplied and installed, then any issues you have land firmly back with the installer to sort out.  Not a luxury you have when you buy a cheap end of line old model and self install it.

[ProDave]

Another small bit of information about the elusive spurious CH14 errors.

 

Today I witnessed a slightly different spurious CH14.  I was in my office which happens to be the room with the hot water cylinder.  I heard the pump start up and the motorised valve for the HW cylinder open, but it only remained on for about a second or 2 before turning off again, barely long enough for the motorised valve to open fully.

 

The operation as explained to me by LG is the unit is supposed to start up and give 10 seconds for the flow rate to meet requirements and if not it will shut down with the CH14 error.  Once more it is not staying on long enough to achieve that.  But this is the first time I have witnessed this spurious behaviour when trying to start DHW heating.  Every other time it has been a short burst of space heating that has tripped it.

 

This has slightly changed my understanding of what was happening.  I had previously thought it was incorrectly registering a very short transient heat demand via the thermostat input which is why I put effort into filtering the thermostat input.  Having witnessed the same behaviour when it calls for heat to the DHW tank I no longer believe that is the case.

 

Instead I think the issue is simply that sometimes when there is a heat demand, it simply does not wait the 10 seconds it should to give time for the motorised valves to open and the pump to get up to speed. Instead it decides in a very much shorter time that the required flow rate has not been met and hence it trips with the CH14 error.

 

This gets me no nearer to a fix. I am now resigned to the fact it will never get fixed. LG don't seem bothered having products out in the field with faulty software and don't seemed bothered by people like me typing their findings that anyone can read and that might influence their decision to buy an LG heat pump.

 

For now the only work around is the mechanical timer to power down the unit in the morning and re boot it, to at least guarantee it will start up in the morning to heat the house.  If it trips at other times of day, like it did just now, it relies on me noticing that something is not working and manually re booting it.