Sanden SanCO2 HPWH, adding WiFi controller

H2OBandit603 · January 20

I have the Sanden Sanco2 GS4-45HPC-D split heat pump water heater. There is a WiFi controller for the Australian version. Why would this not work on mine? I’m unreasonably frustrated by this and am tempted to try it anyway.

“** The Sanden Wifi Controller is designed to operate with the Sanden GAU-A45HPD Heat Pump unit. It is not compatible with other Sanden heat pump units.”

https://www.sanden-hot-water.com.au/wifi-controller/

EdTheHeaterMan · January 20

Is the model number you have compatible with the wifi controller?

Think of it like this. You have a television that has all the controls at the side of the screen and it did not come with a remote control. You need to make all the adjustments on the set itself (like in the 1960s)
You see a Universal Remote on Amazon and purchase it
When it arrives, you find that it will not operate your television. Then you realize your television does not have the receiver to accept remote control signals.

I would talk to the manufacturer (even in Australia) to see if your model number has the necessary receiver to accept the WiFi kit before purchasing it.

Maybe the WiFi signals spin the other way in the southern hemisphere... You know, like whirlpools do

Teemok · January 20

I spoke with Sanco2's about their control policy. There's nothing really to adjust. Certification or approval is likely a reason the controller is AU only. 50hz might be a difference. Hard to say. How does it connect? I'm curious what the wifi controller gets you. Is it just clocks, on off and system state info. They don't allow for settings adjustments because they are protecting the system from abuse while insuring rated efficiency and output.

H2OBandit603 · January 20

I’m happy with their set it and forget it approach to control but the ability to turn on the heat pump even if it hasn’t dropped down to the 113 F thermistor trigger temp would be useful and any information it could provide like tank temp, usage history, energy consumption, error notification make it really desirable in my eyes.

H2OBandit603 · January 20

Here’s the link to the installation manual
https://saheatpumps.com.au/wp-content/uploads/2023/12/Wifi-controller-installation-manual.pdf

Teemok · January 20

I have a resistor I could send you that can be wired to with a switch that spoofs a low tank sensor to the controller starting a heating cycle. I understand you're looking for a wireless option but there is no modbus connection I know of on our models to connect to, even if the wifi module worked with or 60hz mains.

H2OBandit603 · January 20

That would be something I would try for sure.

Jamie Hall · January 20

It may not be completely obvious, but... wi-fi standards (frequencies, band widths, etc.) are not universally standardized. We here in the US may think they are, but... they aren't. Canada is the only other country in the world which uses the North American standard. Nor, for that matter, are cell phones necessarily. That may be why they haven't got a US model.

Teemok · January 20

No modbus connections on our boards makes all other possible reasons secondary. I built a system that uses hydronic fan coil's blower voltage to initiate a brief cycle timer, that closes a relay, that switches the tank sensor to the fixed resistor (5k I think) fooling the controller that the tank temp is low. After the 2 min cycle the relay de-energizes and the rightful tank sensor is reconnected. This gets the HP working preemptively to meet the space heating load longer and without compromising DHW delivery too much. The fan coils water flow rate is set low leading to higher delta T's (110-120F RWT) that the HP needs for moderate efficiency. This only works for very small space heating loads. It's cool to see it work well. A bit Rube Goldberg.

H2OBandit603 · January 21

Are you proposing I install a 5k resistor in the form of a mechanical switch in line that I can cycle to trip the thermistor?

Teemok · January 21

I offer you this: https://www.harvest-thermal.com/
There's no mention of how it effects the sanco2 warranty. Maybe they worked something out with Sanco2.
It has been done is all I'm saying. The skills needed, risks involved and the possibly of voiding the sanco2 warranty should be considered investigated.
Any means that creates a resistance reading that's in the normal tank sensor range, that shows the control a temperature below 113F will start the HP heat cycle. I used a 5.6 ohm 1watt resistor. See lowest chart in pic below.

H2OBandit603 · January 22

I haven’t wrapped my head around how a thermal battery helps yet.

Teemok · January 22

They are using some gimmicky language to appeal to certain types. The storage tank is the thermal battery and they are using it for both DHW and space heating. When the sun shines on your PV solar panels, your HP stores the heat, alternatively or in addition to that the HP only running when your electric rate is low, there by shifting the load with thermal storage out of the peak use times. They are spoofing the tank sensor for sure. Maybe they store hotter than factory settings and trigger early HP cycles. I can't say I know for a fact exactly all they are doing. I do know it is add on/piggy backed to the Sanco2 system without a direct controller interlink.

H2OBandit603 · January 24

https://www.eco2waterheater.com/_files/ugd/e88920_ef70009a73b04c93bdc4c61caf1c8de4.pdf

gen 5 has a modbus

Teemok · January 25

What's the cost if it doesn't work? $350? I guess you could sell it on AU ebay if 60HZ doesn't hurt it?

bjohnhy · October 16

I wanted to share my experience with adding wifi "smart" controls to my Sanco2 Gen4 GS4-45HPC-D

I live in the Seattle area. I have 3 tanks to act as "thermal batteries" for a combi set up.

Re the smart controls, i have added 2 different modifications that allow different controls noted below.

Remotely Set the allowable operation schedule via app on my phone. And the option of turning heat pump off automatically at a lower cold inlet temp (lower than factory 122F), this is initially set manually at the switch and not via app. I used the "Dry Contact Switching" feature, aka "unit start input" that comes with SanCO2 unit. I cut the white wire loop and routed 18 gauge wire to the coldest tank. The dry contact then goes through a 3rd party temperature control switch purchased on amazon, link below. I have this switch powered by a 12v power adapter that is plugged in to a standard 120 volt smart plug (Meross, but could be any brand smart plug). I control the sanco2 allowable operation schedule via the Meross smart app. I have the thermometer of that same switch mounted to the cold inlet line to HP, and can adjust the temperature setting manually on that switch down to a lower temp that will automatically turn off HP set temp, say 118F (but it can be adjusted in 0.5C degree increments) as opposed the default of 122F of the factory HP. I plan to expand this modification to turn off Sanco2 when outside temp is below 32F or so (my radiant system has NG back up) https://a.co/d/iycyEGc

2. The other "smart" control has to do with switching which tank (I have a thermistor in 2 of the tanks) the SanCO2 HP uses to decide when to turn on. I want the system to take advantage of the warmest part of day (11-2pm in winter). So i have used the switch below to toggle the wiring between 2 tanks. The switch below has its own smart app, eWeLink, which I have set to toggle the wiring to the cold tank thermistor at 11:00 a.m, and then back to the middle tank thermistor at 2pm, therefore the SanCO2 is more likely to take advantage of the warmest hours of the day.

https://a.co/d/2r7wmej

*if the thermistor wiring is left open, the HP will shut off. But if its toggled immediately to the other tank, it will continue to operate until the cold inlet reaches 122F (or other end trigger as described in #1).

* i can vouch that the two tank temperature thermistors that i have follow the resistance scale noted in chart posted above.

Sanden SanCO2 HPWH, adding WiFi controller

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