The Sunamp Optimino xPlus Boiler + PV Key (part code VF02) configures a Sunamp Thermino xPlus heat battery to be charged by a system boiler and to accept surplus solar PV electricity through a compatible solar diverter. Sunamp calls it the vfPV key: “vf” for the volt-free boiler connection and “PV” for solar.
It is the key to choose when the boiler stays as the main heat source but solar generation should take some of the load. The xPlus reduces carbon emissions and gas consumption when charged by a system boiler, with the grid as backup, and adding VF02 lets free PV electricity top up the store. Paired with a combi boiler, the xPlus can also pre-heat the cold supply for the combi.
Because the xPlus is built around Optimino technology, this is a key swap, not a new cylinder. Start with the boiler-only VF01 key and step up to VF02 when solar arrives, or move on to a heat pump key later, all without replacing the heat battery. VF02 works with the four solar diverters Sunamp documents: the 4-Noks Power Reducer SA, myenergi eddi, my-PV AC·THOR and Power Diverter Model 3.
VF02
Manufacturer part code
xPlus
150, 210 and 300 models
Boiler + PV
Energy sources enabled
4
Documented solar diverters
10-year
Warranty on xPlus heating element
Choose the right key for your heat source
VF02 is for a
system boiler with solar PV. For a boiler with no solar use
VF01. For a heat pump use the brand-specific
hp (01) or hpPV (02) key, see our
Optimino Keys for Heat Pumps range. VF02 is for the
Thermino xPlus only; a Thermino ePlus takes the PV02 key.
A solar diverter is required and sold separately
The key enables PV charging on the heat battery; a compatible solar diverter then controls how surplus solar power is sent to it. The diverter is not included with the key.
Electrical safety and scald protection
Wiring must be carried out by a competent person in line with BS 7671. Sunamp warns of a risk of electric shock from a potential dual supply, so isolate the heat battery, boiler and solar diverter supplies before working. In line with UK Building Regulations, Sunamp advises fitting a hot water tempering valve at the outlet to prevent the risk of scalding (recommended TMV setting 45–55°C).
Key features and benefits
Boiler and solar PV on one key
VF02 sets the xPlus up for system boiler charging through a volt-free connection and for solar PV charging via a diverter.
Cut gas use, keep the boiler
The xPlus reduces gas consumption and carbon emissions when charged by a system boiler, with the grid as backup. PV adds free electricity on top.
Four documented diverters
Works with the 4-Noks Power Reducer SA, myenergi eddi, my-PV AC·THOR and Power Diverter Model 3, each with Sunamp wiring and settings (D0085).
A staged route to heat pumps
Start with VF01, add solar with VF02, then swap to a heat pump key when the boiler is retired. No new heat battery at any stage.
Compact, low-loss storage
The xPlus is up to 4x smaller than the indirect cylinder it replaces, Energy Class A+, with heat loss of 0.67 to 0.84 kWh per 24 hours.
Mains pressure and low maintenance
High-flow mains-pressure hot water (up to 25 L/min on the 300), no mandatory annual maintenance, minimal Legionella risk and a 10-year warranty on the heating element.
Technical specification
Key identity
Product
Optimino xPlus Boiler + PV key (vfPV key)
Manufacturer part code
VF02
Key type
Optimino energy-source key (plug-in)
Energy sources enabled
System boiler (volt-free) plus solar PV
Boiler-only alternative
VF01
Compatibility
Heat battery
Thermino xPlus 150, 210 and 300
Thermino ePlus
Not applicable. ePlus uses the PV02 key for solar PV
Heat pump systems
Use the brand-specific hp (01) or hpPV (02) key instead
Compatible solar diverters
4-Noks Power Reducer SA; myenergi eddi; my-PV AC·THOR; Power Diverter Model 3
Solar diverter included
No. Required, sold separately
Thermino xPlus heat battery (Sunamp data sheet)
Models
150 xPlus · 210 xPlus · 300 xPlus
Equivalent hot water cylinder size
128 L · 192 L · 256 L
V40 (litres of hot water at 40°C)
167 L · 271 L · 333 L
Heat loss rate
0.67 kWh/24h (28.1 W) · 0.77 kWh/24h (32.1 W) · 0.84 kWh/24h (34.9 W)
Energy efficiency rating class
A+
Heating element (230 V, 50 Hz)
1,800 W or 2,800 W
Manufacturer part numbers, 1,800 W
BKP-KNW-AVZ-1 · BNP-KNW-AVZ-1 · BRP-KNW-AVZ-1
Manufacturer part numbers, 2,800 W
DKP-KNW-AVZ-1 · DNP-KNW-AVZ-1 · DRP-KNW-AVZ-1
Recommended maximum flow rate
15 L/min · 20 L/min · 25 L/min
Minimum mains supply pressure
1.5 bar (0.15 MPa)
Maximum working pressure
5 bar (0.5 MPa)
Recommended TMV temperature
45–55°C
Product weight in use
136 kg · 187 kg · 233 kg
Dimensions (W × D × H)
365 × 575 × 640 mm (150) · 870 mm (210) · 1050 mm (300); pipe access on 3 sides
Installation and documentation
Fitting
Plug-in key for the heat battery’s Optimino controller; swap the key to change energy source, no new heat battery needed
Installer
Competent person; isolate heat battery, boiler and solar diverter supplies before working
Heat battery manual
D0084 Thermino xPlus installation and user instructions
PV wiring and settings
D0085 (4-Noks: 4S; myenergi eddi: MI; my-PV AC·THOR: MV; Power Diverter Model 3: PR)
System schematics
SC01120-00 xPlus and boiler; SC01420-00 xPlus with boiler and solar PV
Technical notes
D0109 volt-free timer wiring; D0093 back-up electric mode; D0104 mandatory plumbing components; D0114 cold commissioning
Frequently asked questions
What does the Sunamp Optimino xPlus Boiler + PV key (VF02) do?
It configures a Thermino xPlus to be charged by a system boiler through a volt-free connection and to accept surplus solar PV electricity from a compatible diverter. Sunamp calls it the vfPV key.
What is the difference between VF01 and VF02?
VF01 is the boiler-only key. VF02 is the boiler + PV key. You can start on VF01 and move to VF02 later when solar PV is installed, without replacing the heat battery.
Do I need a solar diverter as well?
Yes. A compatible solar diverter is required and sold separately. Sunamp documents the 4-Noks Power Reducer SA, myenergi eddi, my-PV AC·THOR and Power Diverter Model 3, with wiring and settings in its D0085 documents.
Can I use VF02 with a combi boiler?
The xPlus is designed to work with system boilers, and Sunamp notes that when paired with a combi boiler the battery can help drive savings by pre-heating for the combi. Check the xPlus manual (D0084) and schematics for your arrangement.
Can I switch to a heat pump later?
Yes. That is the purpose of Optimino. When a heat pump replaces the boiler, swap to the hp key (or hpPV key with solar) that matches your heat pump brand and series. The xPlus stays in place.
Does VF02 work with a Thermino ePlus?
No. VF02 is for the Thermino xPlus. A Thermino ePlus adds solar PV with the PV02 key.
