Reclaim heat pump HWS

Reclaim Energy heat pump controller 2.0+ comes with wifi capability & iOS/Android app.
It would be great be integrate to monitor & control the configurable components of the system.

Searched & didn’t see this requested elsewhere in the Feature Requests, happy to be corrected.

Using Mode 6 setting (from memory) on the v2.0 controller you can already control this with a HA enabled dry contact wired to the “remote Input” terminals on the controller. Don’t need feedback from the system, as it will heat water until water is hot enough all by itself. Input enables triggering heating cycle when HA determines it is most beneficial (for example when there is sufficient solar power to do it).

Mine has a v1 controller and so lacks the capability above, but am considering a small hardware mod to make it work.

I’ve just had one of these units installed - the biggest 400 litre unit with stainless tank - and it came with the version 1.1 controller.

There’s a mikroBUS header on the board and it uses a Microchip PIC16F18876 controller. It also has the “remote” pins which you can bridge to force the unit to start “charging” (see my post below on why I refer to this as a thermal battery).

Some additional notes on potential automation of the Reclaim Heat Pump hot water system (and I suppose, others that use the same principles) are important.

TL;DR - please view this as a thermal battery not just a hot water system. The tank size is much larger than it is for a gas hot water tank. The temperature sensor is more like a binary “state of charge” reading (i.e., it’s fully charged, or not), and it is the “stratification layers” in the tank (and the temperature of each of these layers) that dictates the state of charge. Those are very hard to measure.

Another way to look at the state of charge for this system is to take your traditional battery charge indicator (like you see on a mobile phone) and turn it upside down. When the charge is low, there will only be one bar but it’s at the top of the indicator. For a full charge, all the bars will show in the battery indicator, but as you deplete the battery, it’s the bars at the bottom of the indicator which are consumed. As long as there is “charge” in the tank, you can consume it, and it will be hot.

It is very difficult (but I suppose not impossible) to try and use the temperature sensor as a battery state of charge indicator. If you were to log the temperature sensor, the curve is rather exponential. It sits as a very low temperature for hours, and then will rapidly jump up late in the charge cycle, so as I said earlier it’s almost a binary True/False. Without multiple temperature sensors mounted all the way up the tank, or using ultrasonics/thermal imaging, it’s going to be hard to get an accurate “state of charge” though. I would also say it’s not necessary, and we should just focus on boost control if and when you have a tank size which turns out to be too small for your household when using the built-in power saving modes of the unit.

What Reclaim uses the temperature sensor for is really only two things:

  1. To know when the system is not fully “charged” with hot water
  2. To avoid short-cycling the heat pump. They wait for the temperature at the sensor level to drop a fair bit before the heat pump kicks back in (aka “recharges”).

Some notes on its operation:

  • Water is pulled from the bottom of the tank into the heat pump
  • The water returned to the tank from the heat pump is always 63C as it exits the heat pump. The method by which it ensures that the water leaving the heat pump is 63C is how hard the compressor is working and how fast the water pump is operating. Water not 63C? Run the compressor harder or slow the pump down (or both).
  • The water from the heat pump is returned to the top of the tank, so as to provide “fast hot water recovery” and “excellent hot water stratification”. Stratification being the layers of water in the tank and the different temperatures of those layers
  • The water temperature sensor is close to the bottom of the unit
  • The water temperature sensor can remain “stuck” at a fairly low temperature, even while the water at the top of the tank is 63C. The system monitors this temperature of course and controls the unit based on that temperature. When I had mine fitted yesterday, the temperature sensor in the tank read 17C for five hours, however after only two of those hours, three people had fairly long hot showers and did not run out of hot water.

If you’re curious why the heat pump heats the cold water in the bottom of the tank and returns the heated water to the top of the tank, it’s due to thermodynamics. Here’s what ChatGPT has to say about that:

  1. Faster hot water delivery: When the hottest water is at the top of the tank, it is readily available for delivery when needed. This reduces the time it takes to get hot water at the tap.
  2. Energy efficiency: By maintaining stratification in the storage tank, the energy used to heat the water can be reduced. This is because the colder water at the bottom of the tank requires less energy to heat than if the water were mixed.
  3. Reduced heat loss: Stratification minimizes heat loss through the walls of the tank, since the cold water at the bottom acts as a barrier, reducing the temperature difference between the stored hot water and the surrounding environment.
  4. Improved system performance: Systems designed to take advantage of stratification can deliver hot water more efficiently and effectively, increasing overall performance.
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For my own sake, what I’m going to work on with this unit is direct control over when the unit charges based not just on the times of day that my PV system is likely to be working but also:

  • If it’s daytime but there is little to no sun
  • If it’s peak or off-peak power time
  • State of charge of my Powerwall

How much money I can save using more intelligence sources such as these, compared to the in-built modes of the unit is of course debatable. But none of us are here because we weren’t up for burning time on ideas that might not pan out.

Did you manage to make your modification and add it to hass?
I’m definitely interested in this solution.

I’m in the same boat as you with v1. What mod where you thinking about doing?

Sorry - haven’t been logged in for a while. Was planning just to solder a pair of wires to the terminals for the Boost button and feed them to a HA controlled relay contact.

Guaranteed to start a boost function when requested.
Also guaranteed to invalidate any remaining warranty.
Depending on skill, may introduce other unexpected issues if anything else on the board gets bridged or damaged.

I have the plan - but am still building up the courage… :slight_smile:

I did explicitly ask Reclaim tech support about the function of the Remote terminals on the v1.1 controller, and they only said they were provided “for future development”. I have not done any experimenting yet, but assumed they may have been connected to a micro-controller input without software to respond to it. If as you say it does indeed trigger a boost function, then that is exactly what I was wanting.

I have my system connected via a contactor that switches supply to the HWS from either J Tariff (off peak), or M Tariff (peak) depending what is available at the time. The Controller is set to Mode 3, and the time clock is offset from the real time by a sufficient amount that mode 3 kicks in just after my J Tariff becomes available (it is controlled by a supply authority timeclock). So it automatically heats the HWS from off peak power, unless I hit the boost switch to manually heat it from solar power while available. Solar power also charges my house battery, and the EV hybrid in the shed, so using HA to control it while I’m out is a whole lot better than HA triggering a voice announcement in my office when the conditions are right - telling me to go hit the button on the HWS. It almost always happens in the middle of a Zoom meeting, so its good for comic relief if nothing else…

Yes, would be great to at least monitor and graph tank temperature, and heat pump on/off status.

The ‘boost’ option is #6 for V1.1 controller & #7 for V2 controller. The manual states ‘One shot boost is activated by a dry contact/modbus signal from home management or PV inverters or dry contact smart switches. This is called “Remote” option.’
So, triggering the contacts should work (but, no doubt, would void warranty).

However, you can control the on/off state of the heat pump with a relay (eg Shelly plus 1pm). Wire the relay into the power circuit and set Option #1 on the pump (run 24/7) The pump will only run when the relay is on & the pump is triggered by the thermocouple indicating that water temp has dropped below the set-point.

I have 2 Sanden heat pumps (same pump as Reclaim, different control electronics) running like this. The pumps are, essentially, ‘on’ all the time but power to the pumps is controlled by the relays. Automations turn the relays on & off based on time & indoor/outdoor temperatures.

My pumps are driving a closed hydronic heating system so legionnaire bacteria isn’t a consideration. However, if you are running domestic hot water, you need to have an automation that ensures the pump heats to 60deg once every week (at the very least).

I’ve got a v1.1 controller and I wrote to Reclaim asking if I can upgrade to the new v2 controller. They wrote back with:

I think you have a old heat pump, the V2 heat pump only compatible with V2 controller. V2 heat pump model id is as below and you can check on your nameplate of heat pump: EHPE-4550P-A

Since the controller is made by Senztek I wrote to them asking if there is anyway to get the temperature and start the heat pump, even if it means developing an arduino board to talk to the controller in serial via the mikrobus connections. I’ll report back when I hear from them.

They gave you the wrong info. Page 3 gives details on the remote terminals:

or Page 6:

But note that all this does is kick off a full heat cycle. It does not allow you to turn the heat pump on and off. I was hoping I could do that dependant on available solar but it can’t. Also worth noting that it will automatically turn it on all by itself: “The controller automatically manages Legionella safety, heating once a day if the Legionella safe temperature has not been attained during the day.”

What impact does it have on the heat pump if you happen to cut the power while it is running. I dont think they like having the power cut off while the compressor is running.

The heat pumps must be sufficiently resilient to handle a power outage, the effect of which is the same as switching a relay.

I’ve been killing power to the heat pumps this winter without any issue thus far. Often the heat pumps are in idle state when an automation (or a manual override) switches them off but some of the time they have been working at full power.

Regarding the v1.1 controllers, I wrote to Senztek asking if there is anyway to get the temperature and start the heat pump and this was their reply:

Reply from our Tech Engineer as follows;

The Reclaim controller does not have comms implemented, the MikroBus connections were put in place for a potential future upgrade.

Not unexpected.

FYI, I spoke to my hydronics plumber about killing power to the heat pumps whilst in operation. He confirmed that turning off power to the heat pump (even when running) should not harm the pump.

I’ve left my system running 24/7 for a few months and with a family of 5 who take long showers (teenage boys need their, ah, privacy, shall we say), the system consumes about 6kWh per day, sometimes up to 8kWh.

I doubt that it needs all of that power however, so I’m going to alter the system to only come on under the following circumstances:

  • When power is off peak (configured via the controller on the Reclaim unit)
  • When the ceiling fan in a bathroom comes on
  • When we’re exporting power to the grid

The latter two will be controlled via Home Assistant and the “boost” pins on the controller using an ESP32 coupled with a relay.

Let me add some detail on what I meant previously about the system not needing to be on all the time. The heat pump will come on and start to heat the tank once the tank temperature drops to a certain value. Setting it to 24/7 operation basically means it tries to make sure it has all of its available capacity at any given time, but it spends more time each day heating water in the “inefficient” range; that is, it takes a lot of energy to heat the water to 65C but much less to heat it a little bit.

I believe the system is more efficient if it only does one complete heat cycle per day rather than the 2-3 cycles mine runs at when allowed to operate the heat pump 24/7, due to how many showers we have.

If not allowing it to heat 24/7 with houses that have many occupants, my hypothesis is that having the heat pump run when hot water is being used in showers means that the amount of hot water lost during that shower period is reduced. I can then leave the heat pump to otherwise only operate when it’s off-peak power (or excess solar is being generated). Hopefully, there will then not be any times where there is inadequate hot water.

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It takes exactly the same amount of energy to heat a volume of water from, say, 25 to 26deg as it does from 58 to 59deg. Any energy ‘inefficiencies’ are in the start-up phase of the pump, in heat loss from the tank and in the outside air temperature that the heat pump uses for it’s heat source (ie running the heat pump in cooler overnight temperatures is less efficient than warmer daytime temperatures).

Yes, 1 cycle will be more efficient than 2-3 cycles but it’s marginal (in the start-up time). Highest efficiency will be achieved by running the pump in the warmer times of the day (as far as possible).

I’m interested to hear how you go with tapping into the ‘boost’ pins.