Any way to monitor HVAC refrigerant lines (e.g., mini-split or Air to Air heat pump)?

Is there such a thing as a “heat meter” for refrigerant lines (R410)? Or any guidance on monitoring approaches that can identify energy flow in and out of the outdoor units?

I was all excited about the heat pump monitoring, but seems that the system is all for air-to-water heat pumps.

I’m US based and have a centralized ducted air-to-air heat pump, where the outdoor unit is connected to the inside unit using refrigerant lines. Specifically we have Mitsubishi Electric MXZ_4C36NAHZ_U1 outdoor and SVZ-KP36NA indoor.

Apologies if this is in the wrong place, feel free to suggest other places to ask.

Right place for the question, James, but I think not easy to answer if you want any precision.

I assume you’ll know your temperatures (refrigerant and air into and out of your indoor unit) from your remote display, but not the flows you’d need to make the calculation.
Your operating manual doesn’t help much. Have you a technical manual?
As a rough guide you could use the air flows shown on p15 of the op manual for L/M/H settings and use Q = m.Cp.deltaT on the air side.


Thanks Sarah. At present I don’t have any insights, just the standard thermostat controller that says the set point and what the thermostat currently senses inside. About the only insight I know I could get is to hook up an electrical monitor to know the power draw of the outdoor unit.

When you say “know your temperatures” do you mean that there would already be some way to know the temperature of the refrigerant coming out of the outdoor unit? Is that something that a Mitsubishi technician could get access to through the board?

I’m not familiar with Mitsubishi gear, James, but it all depends on which controller model you have for your heat pump. (The diagram on p7 of your op manual looks like an FTC5.)

I suggest you find out which controller you have, and search for the model number on the forum (the magnifying glass symbol to the left of your profile image top right of screen). This should take you to any relevant discussions on capability.

It might also be worth asking your installer (or even the Mitsubishi tech helpline) to see what monitoring hardware might be available.

You might also be able to clip a CT meter on the outdoor unit power supply to establish its power requirement.