chris47

Thanks for that; I'll try the LSV route first

see attached 22/9/25 graph; is this an example of 'short cycling'? According to online AI: The LG Therma V R32 monobloc air-to-water heat pump does not have a built-in immersion heater (IH). The monobloc unit is designed as a self-contained outdoor unit for heating and hot water that connects directly to the domestic water system. I noticed that the WC kicks in when outside temp drops below 12°C. During overnight period, between 00:00 & 05:00, schedules for DHW & CH are OFF so it seems that the power draw is to satisfy the buffer using WC (AI). Since there is no IH available for use, I have to assume the AWHP is running at these times at a low (modulated) level. If this is an example of 'short cycling' what can I change to help reduce the effect? My World Heat DHW cylinder has a built in buffer tank at the base. There are 4 connections to this buffer tank which seems to indicate it is a 'hydronic seperator' preventing the AWHP's internal pump interfering with the CH pump attached the the CH circuit of the DHW tank. There is no IH fitted to this buffer tank. My 'sterilisation' IH is switched OFF permanently. My Octopus Cosy tariff has 3 daily cheap rate slots but the AWHP seems to be able to run at any time, contolled by WC. This means it could run during the most expensive time between 16:00 & 19:00 (3 times cheap rate!). Is there any way to mitigate this effect? Still no response from LG!

I do have a battery - Give Energy 9.6kWh with 3.1kW AC coupled inverter:) I haven't discounted the possibility that the AWHP is simply satisfying the buffer; I intend fitting a wireless temp sensor to the buffer feed pipe so I can determine if indeed the heating of the buffer is the cause of the spikes. Do you know the link to 'ways to wire controls when a buffer is present' you referred to above?

Dillsue said 'If all your scheduling is done within the Honeywell programmer can you turn that off overnight and see if the HP continues starting up........' The Honeywell programmer is for CH only; DHW is controlled by the LG programmer. Rather than running 24/7 I'm timing my start/stops for DHW to match Octopus Cosy tariff that gives me 3 daily cheap rate slots totalling 8 hours @ 12.9p/kWh. The other rates are 3 day rate slots totalling 13 hours @ 26.31p/kWh & a 3 hour slot @ 39.46p/kWh. I'm timing my start/stops for CH using all the above slots but avoiding the expensive slot of 39.46p/kWh During my 'first' winter coming up using an AWHP I will balance the radiator temps using the lockshields (TRV's fully open) & then adjust the TRV's as you suggested. I also have a Give Energy battery backup which I can charge with solar PV & Octopus Cosy cheap rate to help reduce the running costs of the AWHP. I think this coming winter is going to be a lot of 'trial & error' & a steep learning curve. ps I turned OFF the main AWHP isolator switch Friday night between 01:00 & 07:00 & all the power draw spikes disappeared; proving it was the AWHP & or an internal AWHP electrical heater running that caused these 'spikes'. I noticed from the installation manual that their is a reference to 2 DIP switches that control an 'electrical heater' but it doesn't say whether it's the buffer tank heater (which I don't have) or some other heater (like the Willis heater referred to earlier in this post). I shall be installing a wireless temperature sensor in the DHW tank to help determine whether CH or DHW heating is being supplied by the AWHP. I've sent the initial data from the start of this post to LG support & will report back their suggestions/comments if any! Thanks to everyone for you input & I will post again when I have something to report.

I appreciate that the overnight power draw is not wasted but is heating the DHW tank, but my concern is the relatively 'short cycling' damaging the CoP and/or compressor life.

I'll try to find the route to controlllng the frost stat temp settings I discovered by accident.

The Honeywell wireless thermostat was part of the AWHP installation

HW schedule: 06:00 to 07:00 13:00 to 16:00 22:00 to 00:00 As can be seen above, the overnight power draws are when DHW demand is OFF

Can't it be disconnected via LG control panel on HW tank?

Not without staying up all night:) I'll give it a try tonight

I'm in Bristol (South West)

There is a a buffer tank between AWHP and emitters, built into the base of the HW tank but no IH is installed there. Yes, this is my first winter

Thanks for your comments JohnMo My house is well insulated (EPC high C rating) so heat loss is low; however, the thermostat schedule is OFF until 05:00 but the power draw is much earlier. My AWHP was only installed in April 2025 so my installer stated there is no historical data yet. He will setup weather compensation after 1 year's running.

Thanks for your comments JamesPa There is a a buffer tank between AWHP and emitters, built into the base of the HW tank but no IH is installed there

Thanks for your comments ProDave The Shelly EM GEN3 monitors the AWHP (LG Therma V AWHP on right hand side of Shelley app). The power draws are 1.5-2kW approx, far larger than a circulating pump would draw. There is an adjustable frost protection routine but it's not well documented but whatever I set it to doesn't appear to make any difference to the timing of the power draw. There is no immersion boost heater installed in the buffer tank as installers state they don't fit them in UK installations because our climate is not cold enough. The LG installation manual is not well written but my thinking is that there is a low power immersion heater (IH) fitted inside the LG AWHP monobloc cabinet. This IH is switching on, at approx hourly intervals, as a frost protection measure. The legonella IH is fitted but have switched it off, so the power draw is not due to this. On the give energy graph dated 11/9/25, the power draws between 00:00 & 02:30 are typical of an inverted (modulating) AWHP compressor draw. Between 02:30 & 04:40 the power draws are more like an IH. I wonder if it's worth contacting LG support?

Hi All Compare the 3 attached photos of my give energy & shelley apps; it shows these odd early morning power draws of my LG AWHP. The give energy photo dated 7/9/25 is what I expect & have seen over the last few months; the give energy photo dated 11/9/25 shows these weird spikes occurring every hour or so; the shelley photo shows overnight AWHP consumption of around 500Wh every hour throughout the night whci seems to tally with the give energy graph of 11/9/25 I've checked the CH schedule on the Honeywell Home room thermostat as follows: P1 starts at 05:00 - CH ON P2 ends at 16:00 - CH OFF P3 starts at 19:00 - CH ON P4 ends at 23:50 - CH OFF HW schedule: 06:00 to 07:00 13:00 to 16:00 22:00 to 00:00 The lowest temp last night (11/9/25) was 12°C between 03:00 & 06:00; any ideas about why this AWHP behaving like this would be appreciated.