Temperature Control

K043 Multi-Tariff Boiler Thermostat

Programmable boiler thermostat with tariff-aware switching, ten memory registers plus weekend register, water-temperature range +10 to +80 °C, single or dual heater relays.

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Overview

K043 is our boiler-thermostat platform. It manages the resistive heaters in a hot-water tank against the operator-set water temperature and the local supplier tariff calendar, switching the heater off during peak rates and back on at off-peak. Ten programmable schedule slots plus a weekend register, hour/minute/day/month/year RTC, and a consumed-electricity readout via the W key. Four configurations on one board: single or dual relay, 1.5 kW or 2 kW per relay, selected at order time.

Key features

Tariff-aware heater scheduling against local supplier calendar
Ten programmable set-points + separate weekend register
Economy-mode shedding indicator (LED E)
Consumed-electricity display via W key
Four variants share one board and one BOM

Variants

K043 (dual, 1.5 kW)

Two independent heater relays, 1.5 kW each. Economy-mode shedding.

Number of relays: 2 (independent)
Heater rating per relay: 1.5 kW
Order code: K043

K043-S (dual, 2 kW)

Two independent heater relays, 2 kW each.

Number of relays: 2 (independent)
Heater rating per relay: 2 kW
Order code: K043-S

K043-D (single, 1.5 kW)

One heater relay, 1.5 kW.

Number of relays: 1
Heater rating: 1.5 kW
Order code: K043-D

K043-V (single, 2 kW)

One heater relay, 2 kW.

Number of relays: 1
Heater rating: 2 kW
Order code: K043-V

How it is used

Domestic hot-water boilers in homes connected to multi-tariff supplier contracts. K043 schedules the resistive heater(s) against the local supplier tariff calendar, running heaters during off-peak rates and shedding during peak. Economy mode (LED E) indicates load shedding. Operator-readable kWh display via the W key gives end-customer transparency.

How we build it

Single-board boiler-thermostat platform built on our DDM Novastar line. SPR-45 prints SAC305 paste with extra deposit on the relay coil drive pads. LS60 places the temperature ADC, MCU, RTC crystal, lithium backup holder, LCD ZIF, kWh-accumulator electronics, and relay coil driver under vision check. Relays (1 or 2, 1.5 kW or 2 kW each) selected at order time and placed by hand before reflow. GF 120HC reflows at 245 °C. AOI on every joint.

Assembled on our in-house Novastar SMT line: SPR-45, LS60, GF-120HT.

Optical inspection and test

AOI inspects placement, relay polarity, and solder fillet on relay contact pads. Functional check: relay switch at water-temperature set-point, RTC and tariff scheduling behaviour, kWh accumulator increment against a reference current source, backup retention.

Design specifications

Mechanical

Wall-mount enclosure with LCD and front-panel buttons (On, Set, ↑, ↓, W). LED R for relay state, LED E for economy mode.

Electrical

220 V AC at 50 Hz. Relay rating per variant: 1.5 kW or 2 kW per relay, 1 or 2 relays.

Environmental

Indoor installation. Pre-set water temperature range +10 to +80 °C.

Communication

No external comms. RTC for tariff calendar, ten programmable schedule points plus weekend register.

Specifications

Nominal voltage: 220 V AC, 50 Hz
Pre-set temperature range: +10 to +80 °C
Memory registers: 10 weekday + 1 weekend
Front-panel display: LCD: time hh:mm + day + water temp + set-point + date dd/mm/yy
Indicators: LED R (relay state), LED E (economy mode)
Buttons: On, Set, ↑, ↓, W (consumed kWh)