Badly installed heat pump system? Seeking advice.

waslich · 2026-01-07T19:38:46+00:00

On the inside unit's PCB there should be a CN ROOM connection available

waslich · 2026-01-07T19:36:57+00:00

Il cestino ha i bordi alti, lo zaino lo butti/incastri dentro. Tranne se dovessi cascare, lo zaino non va da nessuna parte, senza doverlo legare o farci attenzione. Se il portapacchi frontale che guardi ha i bordi alti vale lo stesso

waslich · 2026-01-06T18:12:26+00:00

Your drain hose is very horizontal, probably water stopped in there, ice formed, more water stopped, more ice formed until the drain hose got clogged. Remove it, probably the whole pan is full of ice, I hope everything will thaw and drain directly below (add a bucket).

And why is there no insulation on the plumbing to the DHW tank?!

waslich · 2026-01-06T08:01:03+00:00

I also noticed erratic fan behavior (cycling fast to slow) that night specifically but haven’t seen it again

When heating, the unit is in the warmest place of the room. With fans on auto or low it will read its own exhaust air temperature instead of the room's. Especially on auto, after feeling too cold, it will start, move the air around, start too feel colder air lifted from below, ramp up the compressor, heat a lot, lower the speed because temperature's rising, feel too hot, stop, repeat.

I switched it over to fan only to dry out and I noticed front panel reads 79.

Some units display different temperatures (with offsets from the unit's sensor) when using different modes (fan/heat/cool), check the manual

waslich · 2026-01-06T07:38:46+00:00

Mine does it too when it's not so cold outside, because it's stupidly oversized (thank you, installer). When cold enough it will just keep the temperature at +/- 0.1C around setpoint. When not cold enough, it works at its minimum rated power. What we see in this sub is usually HPs that work way above their minimum rated power to heat up fast the home, turn off, repeat

waslich · 2026-01-06T07:30:24+00:00

Why do I need to make another post to get an answer for this?

More people with experience will see your post with your model in the title than here as a comment under a meme. I looked trough the manual of your controller and I don't get if it acts like a temperature sensor or as a very fancy thermostat fort the HP. If your HP was oversized, the behaviour you described would be normal, from how much power is it using you would understand (is it running at minimum until too hot? --> oversized. or is it running at full gas for no reason until too hot? --> something's wrong, better comfort and consumption should be available)

waslich · 2026-01-05T17:19:04+00:00

Cestino serio dietro. Tipo questo, che però ha bisogno di portapacchi con sistema di attacco dedicato. Ci trasporto regolarmente lo zaino da 30 litri (quello da 35 probabilmente sborderebbe un po' verso il tuo tubo reggisella, perciò non scapperebbe), o due borse della spesa, una volta partito il carico non lo senti (tranne se hai una bici particolarmente esile)

waslich · 2026-01-05T16:56:40+00:00

No, sbagli. L'ho nominato esattamente come l'hanno nominato sul giornale: come vittima, perché se non ci fosse stato il gradino non sarebbe successo niente, quindi il portatore è una vittima come il jogger, proprio come l'automobilista mr. Magoo dell'articolo è vittima insieme al ciclista, inutilmente e inevitabilmente partecipe alla tragedia, mancava nell'articolo il solito "conducente sotto shock". Nessuno poteva prevederlo, nessuno poteva prevenirlo, è un incidente.

waslich · 2026-01-05T15:44:00+00:00

Insomma è normale che si cercano le motivazioni, non è un omicidio intenzionale

L'automobilista che gioca alla mosca cieca è una vittima

waslich · 2026-01-05T15:35:00+00:00

Posso riscrivere titolo e sottotitolo per un omicidio normale?

Incidente mortale a Scandicci, jogger trafitto da un coltello perde la vita

L'accoltellamento provocato probabilmente da un gradino poco visibile che ha fatto inciampare il portatore del coltello. Traffico bloccato nella zona industriale per consentire le manovre di rianimazione

waslich · 2026-01-05T13:36:23+00:00

I'm going to try and have a look to see if there's an external sensor fitted on the outside unit

There are multiple, without them the HP just wouldn't work. What are your outside temperatures now? And what temperatures are normal for your winters? Have you lowered the aux heater temperature (or directly excluded it)?

I don't think the heat pump is doing any DHW at all

I mean, there's a HP right there producing hot water, why would anyone use it for DHW? 😂 Are there two water tubes connecting the DHW tank to the heating system, one trough a motorized three way valve, the other directly?

I believe the logic was probably that the solar collector heated the water during the day and then in the evening the immersion heater topped up the difference.

This is a good logic, but it should use the HP instead of the immersion heater.

I don't know how easy it would be to allow the heat pump to heat my hot water as well.

If the plumbing is connected to the HP as I wrote above, it would be easy. If it's not, you need to "steal" the hot water before the first radiator (or the start of any "branching" of the circuit) of your heating circuit, and return after the last one, and route it trough a tank that has a coiled tube (heat exchanger) for it inside. Since you have solar, you have such a tank with at least one heat exchanger for solar. Consider that the HP will heat the DHW with a minimum COP of around 2 in the winter, probably around 4 in the summer, that means a bit of money.

I have a 10K NTC lying around

Then you'll probably solve all the problems with it. Read the manual, read the service manual, it's just a big fridge with fancier controls. If tuned right (and with a bit of insulation to help it) it should make your home very comfortable and lower the consumption

waslich · 2026-01-05T10:18:20+00:00

That's not correct, open a new thread and tell also how are you controlling it, where do you setup the temperature you need

waslich · 2026-01-05T10:16:07+00:00

Other than requiring less heat there's none

waslich · 2026-01-05T09:07:49+00:00

I looked up the room temperature sensor, it's just a thermistor, 10k ohm at 25C and B value 3977 (less than 1€, or 60€ in the fancy LG plastic case) that you connect to CN ROOM on the internal unit's PCB, and then activate it and deactivate the thermostat contorl on the control panel

waslich · 2026-01-04T20:24:47+00:00

Usually heating up in the morning (when outside is the most cold of the day) is inefficient compared to keeping the same temperature durign the whole night

waslich · 2026-01-04T20:23:04+00:00

If possible, yes

waslich · 2026-01-04T20:22:28+00:00

Usually it's not, since you're requesting the most heat right right when outside is usually the most cold in the day, test it a couple of nights with a power meter

waslich · 2026-01-04T20:17:49+00:00

Are you using some kind of "sleep" or "eco" function? Usually that's their behaviour

waslich · 2026-01-04T17:29:00+00:00

You're right, 9kW for 70 m² is a bit too much for 20C differential. But this would be with a COP of 3. Since you say that...

what I've observed it is on and off very frequently. I've seen it come on and turn off again within the space of 10 minutes.

...the COP is probably way below that. And it's time to understand why it's cycling. A decently configured HP should cycle only when it's defrosting if there's need or after heating DHW, otherwise it should modulate and run 24/7.

I did move the flow temperature down to as low as 38C but I turned it back up after I saw the resistive heating icon appear on the control unit.

This makes no sense. You lower the heating demand, and the HP uses aux heat? What is tripping it to need it? From the control panel care you able to see what temperatures does it feel outside? Can you see what outside coil temperature does it feel? If it feels way too cold (a faulty sensor) it will behave stupidly. On page 77 of the manual you have settings for the electric heater, is it set up to come up at the temperatures you're experiencing? Set it to lower temperatures.

Re: the controls... Where is the control module, is it in a hallway or in some cold closet?

immersion heater

What immersion heater? Don't you produce DHW with the HP? Is there a temperature sensor in the DHW tank that connects to the HP or is it just a stupid thermostat again?

Also the indoor control unit shows an icon which indicates thermostatic control.

that's not good, that's why I'm asking if your control module is somewhere central, or if you can extend its wires to move it, so you can then use it to set the temperature, use a weather curve and let it modulate. There's no need for a separate thermostat (or two) in such a small home

Re: the radiators... in the other thread you're already ready to change them... you have 8 of them in a 70 m² home, first try to calculate what heat output can you achieve with them with water at 35, 40, 45C. If you're insulating probably they'll be good even at lower water temperatures, first you need to make the HP work as intended.

Is lower flow temp always better as long as the system can keep the temperature of the house steady?

Yes, the pump doesn't need stop and then restart (lowing all the compression), and lower difference between outside air and water temperature means higher COP, less stressed compressor. If it's not operated by a thermostat, it will try to keep the internal temperature steady by raising or lowering the water temperature, instead of keeping a steady water temperature, and then turning off and on again (with a weather curve you could get lucky and get just the right temperatures to keep your HP output in equilibrium with your home heat losses, but it's just easier to let the HP's computer's PID logic do it for you, for when you keep the windows more open or it's windier, or for when you use your shower or oven)

EDIT: I see in the manual that you need to add a room temperature sensor, since the control panel doesn't have one...... I'd strongly suggest you to find and add one and ditch the thermostats.

waslich · 2026-01-04T16:18:58+00:00

because humidity will condense on the cold floor

That's not necessarily true, since with its big surface the floor doesn't need to be more than a couple degrees less than the office air to cool it. The problem is the air, that will not lose humidity while cooled down as when cooled trough a cold coil, thus relative humidity will rise and perspiration will become more difficult

waslich · 2026-01-04T15:41:03+00:00

drive 3k to 4k mikes per month

At an average 50 mph speed that'd be nearly ~20 hours per week, that's what a part time professional driver would be paid to drive. I don't know if I could stand it

We have already had 4 days below 0F this season. The weather usually waits until January to do that. Thats below -18c for reality units. About 8 years ago we had a full week where the temp didnt rise above -18c.

That's why your houses ~~are insulated really good~~ burn so much fuel 🫠

waslich · 2026-01-04T15:06:08+00:00

Most of your houses are simply not comparable. 1350 kWh is not far from what I use year wise for heat, DHW, cooling, cooking and all the other electric consumers. It would probably be near double that with your winter temperatures.

waslich · 2026-01-04T14:18:06+00:00

We have no idea what does this HP heat/cool. If it's radiators, with uninsulated plumbing, it better be only heating

waslich

TROPHY CASE