Inlet water temp change

[MathieuLH44]

Hi,

I have an issue about the Inlet water temp. Sometimes, when the weather is cold, this setting value change too low (lower value asked 40°C, issue value 35°C)

This happen online when I allow the external thermostat

Do you had the same issue ? Maybe is a setting to change ?

[HaiQ31]

I am not sure whether I get your question. Where do you see the correct value und where the one too low? Do you mean, that your inlet temp. value provided by espaltherma does not show the correct value? How is the external thermostat related to espaltherma?

[MathieuLH44]

I set a LW (48°C at -5 and 40°C at 20), but, the inlet temperature drop to about 35°C (by ESPaltherma), and this value is on the screen of the control panel But this happen only when I use the external thermostat

When this happen, the pump shorts cycling, so I think it's not the best for the durability

[HaiQ31]

I still have questions. As I understand so far:

• You use the two-point curve for weather-dependent control.
• P1 equals (20°C, 40°C) with X: ambient, Y: LW setpoint
• P2 equals (-5°C, 45°C)
• reglage loi d'eau A = LWT ?
• reglage loi d'eau P = RWT ?

what I see:

• most of the time your LW and RW are constant.
• sometimes the RW temp rises but the LW temp does not
• sometimes the RW remp rises and the LW temp does as well
• the pump is running for short periods most of the time.
• the pump goes off when EXT rises

what I guess:

• LWT and RWT mixed up? Leaving water temp should be higher then return. Otherwise its cooling.
• you have valves on the emitters that control the flow through the emitters.
• your pump is set to scan mode (not sure how its called in the english manual). -> these two would mean, that your HP does not know the heat demand since no room sensor is connected to the HP itself. Therefore the pump starts every 3min and checks whether RW is getting cold or not. If so the compressor starts, otherwise pump goes back off and waits another 3min. (3-6AM looks like this)
• in case of demand (a few minutes around 18:30 o'clock) both LW and RW rises, but pump goes back off. This happens when EXT Temp rises. Is the highest ambient temp. for heating set to a value near that what EXT shows? This would force the pump off. (two-point curve does not influence this!)

what I miss:

• LW set point (this should show you the calculated set point at the time)
• operation on/off of compressor (can be seen with compressor speed)

I'd be happy to think things over with you, but what I see here is not related to espaltherma sensor. Espaltherma is just the messanger here of what your HP is doing.

edit: add links to *.h files as an example

[MathieuLH44]

I think that the ; loi d'eau P is for the main area loi d'eau A is for the second area (not active) But i'm not sure What do you mean when you say RWT ?

I add a picture of the settings (I tried some little change on the temperatures)

Yes, the LW is constant, but it's under the wanted value

Yesterday, the pump works well after a restart (8h30)

[HaiQ31]

ah okay. I estimated "A" stands for "Avance" which I translated with "leaving water" (LW, leaving the heat pump to the emitter) and "P" stands for "prise d'eau" which I translated with "returning water" (RW, returning water from the emitter back to the heat pump). With "RWT" I mean returning water temperature. To figure out whether something is wrong here or not, I think we need leaving water temperatur and returning water temperatur time series. I add a figure that shows what I mean: blue is the set point for LWT [sic] at the time, yellow is LWT and orange is RWT. You see a lot of peaks over the set point and valleys bellow it.

What you can't see is that the flow rate of the water. This shows the second figure. As you can see, peaks only occure when flow is above 0 L/min. But not every time. This is because the compressor does not heat everytime. You can see this in the last figure Only when heat demand exists the compressor switches on. If no heat demand is left, it goes back off. If you look on the first figure you can see that in the peaks, the spread between RWT and LWT is lower than 4K. It's about 1,5K. For the HP that means that the heat is not needed. To figure out whether there is something wrong at yours, we need all this information.

At 8.30 your water pump went off. As I mentioned: your water pump starts every now and then to scan if heating demand exists. Without the state of your compressor (the actual heat generator), we can't see whether your heating system tries to heat or not.

Do you experience any issue with the heating system, like cold rooms or something else that makes you think something is wrong with it?

edit: add figures as example

[MathieuLH44]

I add the temperature of the leaving water (orange) and of the return temperature (purple)

I restarted the heat pump at 8:30

I see that your heat pump do a lot of short cycle, but, I think it's not good for the durability

Do you speak french ?

[HaiQ31]

I don‘t speak french. I just played around with deepl;)

I see what you mean before the power cycle. But this is not necessarily faulty. If yellow means the set Point of LWT everything works as intended. But why your HP lowers the set Point to this value can‘t be seen here. Do you have schedules set up? Are there further external inputs i.e. room sensors, smart grid,…

After the power cycle, your LWT (orange) looks good and is near the set point. The spread between LWT and RWT looks good as well.

As a side note: that the HP says it is in heating mode does not necessarily mean that it‘s actually producing heat. Depending on your installation, It just means that it performs all necessary operarions and measurments to produce heat (including but not limited to produce heat)

you are right, the HP short-cycles a lot. Since this is because of demand lower than the minimum heating power and no storage it is hard to reduce these.