Using emonHP but with constant parameterized flow value


I installed an air to water heat pump (mitsubishi) recently, and I am looking for some monitoring applications. Unfortunately I saw this site after installation :confused:

My hydraulic circuit is in two parts, primary circuit with heat pump and its own circulator, an hydraulic pressure breaker, and then the secondary (radiator) circuit with its own circulator.
I know the flow rate of the primary circuit, because its speed setting is fixed, it runs all the time, and I have curves of flow rate as function of static pressure external to the heat pump (which is basically almost null because there is 1meter of pipe between heat pump and the pressure breaker bottle)

Furthermore I cannot use the bundle because I don’t have room on my electrical panel for the electricity meters. So what I planned is to have a CT around the live wire supplying the heat pump (at electrical panel level), wired to the emonTX, and heat pump input/output pipes temperature wired to emonTX as well via the RJ45.

So to wrap up I would like to use the emonHP application, but without using the bundle, and using a fixed constant value for flow rate.

I would use emonTX to collect power consumption + flow temps and emonBase to gather data, but i wonder if I can use the emonHP with that setup, and if I can set the flow rate to a fixed value instead of mounting a flowmeter on the pipe.

I know a bit on the computer stuff, so I could fork to do my own stuff from the github, but I don’t know to what extent the emonHP application is specific to a hardware setup, or not.



1 Like

Hello Vianney and welcome!

Do you have an Mitsubishi EcoDan? They usually come with a Sika VFS flow meter and it is possible to piggy back on the analog voltage output that that provides, reading it in parallel with your heat pump. Doing that alongside EmonTx CT power monitoring and DS18B20 temperature sensors will give you the full heat pump dashboard.

I have a custom version of the EmonTx4 firmware that supports reading from this flow meter that I need to publish and document so could help out what that.

1 Like

Hello Tristan !

Thanks for your reply !

Yes it is an ecodan with a sika flowmeter, and yesterday I plugged my voltmeter into that output to check flow rate ^^.

Since this flowmeter always give the same reading for me (due to hydraulic separation between primary and secondary circuits), that is why I was just considering having a constant parameter for the flow rate. There would be no interest for me in having additional wires since the flowrate is always constant as soon as the ecodan is On (which is always the case because it does the DHW as well).

I believe I could start from your version and simply bypass all flowmeter acquisition steps. How did you plug into the sika connector on your side (I’m assuming you’ve got an ecodan as well but maybe it’s not the case) ?

But for the time being it looks like the emontx is out of stock :confused: on the website. And it is indicated that it is 3.4 version, how did you get the 4 version ? Is this just a firmware upgrade ?



The TX4 is the new version. They have just been received from manufacture and will be available soon.

Ok good to know thanks !

And last question, it is not clear from product page whether AC-sensor is provided when purchasing emonTX with wifi option? Do you know ?



No the AC sensor is always additional. The OEM folk have developed their own AC Sensor - EmonVS. That should be clear on the Shop page when it goes live.

I’m not sure whether the Wi-Fi version will be available immediately. The priority is probably the RFM version.