Haier R290 Monobloc

[JohnMo]

Forgot to mention DHW, this was to be by immersion only. Have rethought this, as all the hardware and cables are in place, to switch the 3 port valve. But gone a much simpler layout than previously. Immersion is standalone and not connected to heat pump at all. Any issues with heat pump, just flick immersion on.

 

Routing was always difficult to sensor probe from heat pump to cylinder but that has been solved by repurposing a cable or two not in use, that running through the house. But includes the cable I was going to use for the smart grid switching. One problem solved, one created.

[JohnMo]

Decided after all to stay simple, DHW by immersion, will have plenty of excess solar in summer that will not be generated due to export limits. So better to use it via immersion than loose it.

 

So wiring is complete. Have retained the smart grid switching to allow flow temp boost if I need it for the summer house, have retained the open source monitor system (energy and performance monitoring). So wiring actually done by me, power cable, SG switching 2 core cable, which then connects to inside house via existing trenched SWA cable (already in place for existing HP), this connects to UFH controller, so I have remote (hardwired) manual temp over-ride for summer house temperature. 

 

Once outdoor unit in place it's just power cables and shielded comms cable. A some basic pipe work mods.

 

Image below left to right, isolation switch wiring center and performing), electric meter for heat pump, heat meter for heat pump, Hiaer controller, below that, simple wiring center, then the main control/wiring center for Hiaer heat pump.

 

[JohnMo]

So will be keeping the volumiser, it's in the return line, but after the diverter valve due to because retrofit. So it also had an ESBE diverter, which allowed the volumiser to be bypassed during the production. That bypass isn't needed, so actuator removed and all the insulation tidied up.

 

Before

After

 

Not perfect but much better than it was.

 

Still a filling/flushing valve to sort out, but in the difficult basket 

 

[JohnMo]

Been scratching my head how to set WC curves, one for heating the other for cooling, however I found because the unit was set to auto (auto switching between heat and cool) the menu wasn't visible. However switch to heat or cool and WC menu pop up. Very easy to set, so set a flat curve for cooling 16 deg (well above dew point) flow temp and heating the more normal curve.

 

Will most likely need some adjustment once up and running.

[JohnMo]

On 17/01/2026 at 12:48, JohnMo said:

 

I heat the summer house as part of the same zone as the house, it runs at 18 to 19.5 normally, but sometimes we need it warmer, so I normally use a thermostat to trigger a second setpoint for the heat pump, which works fine and floor just buffers the heat. The Hiaer unit, I will utilise the smart grid connection, and set a 2 Deg uplift in flow temp when the connections across terminals for SG2 (EVU signal) are closed. The same connection can reduce the cooling flow temp should I need it

I decided to change this wiring and use zone 1 and zone 2 control via 3rd party thermostat control. This gives a few advantages

Heat and cooling is switched manually, so use a simple light switch to trigger seasonal changes, it's connected to ASHP and UFH controller, so both are always in exactly the same mode - this is hardwired.

Hydraulically the system runs fully open, zones is purely for different running points and flow temps.

Zone 1 terminals are fitted with a jumper wire, so always on pure WC, so runs in heat or cool depending on seasonal switch position.

Zone 2, is a wireless switch controlled by UFH controller, in winter it allows me to boost summer house temp (only if needed via manual setpoint change on UFH controller), increased flow temp being buffered in to house slab (been doing this for the past year, works well). In summer it allows two set points for cooling, 19 degs flow background via zone 1 temp, if house goes above 23, it moves the flow temp to 17 via zone 2 setpoint. It also includes control set point for humidity, so if house goes above 60% it removes boost function via zone 2 (this will require tuning).

 

A further advantage is zone two has its own WC curves for heating and cooling. Certainly for heating it allows me to fine tune the boost temp uplift required at different outside temps, for summer house which runs a fan coils and not UFH.