# Controller TECH ST28 SIGMA for solid-fuel boiler — fan, CO and DHW pump control, automatic fan speed regulation, black

**URL:** https://aio.lv/en/product--tech-st28sigmabk--11867798
**Data updated:** 2026-03-09 17:44 (EET)
**Category:** Control Systems
**Manufacturer:** TECH
**Manufacturer code:** ST28SIGMABK
**EAN:** 5901445470951
**Warranty:** 2 Years
**Availability:** Available for order
**Price:** 139.99 €
**Prices and availability valid until:** 2026-07-10 23:59
**Price without VAT (21%):** 115.69 EUR
**Can be purchased by legal entities:** Yes (invoice)
**Buy:** https://aio.lv/en/product--tech-st28sigmabk--11867798

## Delivery options

| Delivery method | Delivery time | Cost |
|---|---|---|
| Office pickup (2b. Kengaraga str., Riga, Latvia, LV-1063) | 01.07.2026 | free |
| Pickup points | 06.07.2026 | 1.99 EUR |
| Courier delivery to door | 06.07.2026 | 4.99 EUR |

## Summary description

TECH ST28 SIGMA is a controller designed for solid-fuel (loading) boilers to manage a combustion fan and central heating (CO) plus domestic hot water (DHW/CWU) pumps. The unit provides automatic fan speed regulation based on boiler conditions, coordinating pump switching and safety inputs. It is intended for retrofit or new installations to automate combustion air and pump control in residential boiler systems.

## Long description

TECH ST28 SIGMA is a controller engineered for solid-fuel (loading) boilers to automate the operation of a combustion fan and pumps for central heating (CO) and domestic hot water (DHW). The device monitors basic boiler conditions and adjusts fan speed automatically to maintain efficient combustion while coordinating pump activation and responding to safety inputs. The compact black enclosure is suitable for retrofit upgrades or new installations in residential heating systems.
Advantages
The controller provides automatic fan speed regulation that adapts to changing boiler conditions, reducing manual intervention and improving combustion stability. Integrated pump control for CO and DHW simplifies wiring and system logic by sequencing pump operation according to boiler output and temperature signals. Safety inputs and interlocks allow the unit to respond to fault conditions, supporting safer operation of solid-fuel installations. The device’s compact design and standard electrical connections make it practical to install in existing boiler rooms or new systems.
Suitable for
Solid-fuel (loading) boiler automation in single-family homes
Retrofit projects to add fan and pump control to existing boilers
New residential boiler installations requiring coordinated fan and pump management
Systems where automatic combustion air regulation is needed for fuel efficiency
Key specifications
Functions: automatic fan speed regulation, CO pump control, DHW pump control, safety inputs
Application: solid-fuel loading boilers for residential heating
Housing: compact enclosed unit in black finish suitable for wall or panel mounting
Interfaces: control outputs for fan and pumps, inputs for temperature and safety sensors
Control logic: coordinated sequencing between fan and pump outputs based on boiler signals
How to use
Install the controller according to the system wiring diagram provided by the boiler manufacturer or installer, connecting the combustion fan, CO pump, DHW pump and required sensor or safety inputs. Configure or verify default control parameters so the unit recognizes temperature or pressure signals from the boiler and operates the fan and pumps in the intended sequence. After installation, perform a commissioning check to confirm automatic fan speed adjustment, correct pump sequencing and proper response to safety inputs.
Usage recommendations
Use the controller with compatible solid-fuel boilers and fans specified by the system designer. Ensure sensors and safety devices are installed and regularly tested. Commission the unit after installation and include it in routine heating system maintenance to maintain combustion efficiency and safe operation.

## FAQ

### How much does the Controller TECH ST28 SIGMA for solid-fuel boilers cost, and is it available for purchase?

The price is 139.99 € (valid at the time of publication and already includes all taxes). The item is available for order — 1 pcs. are in stock, and you can place your purchase right now with delivery across Latvia and Europe or choose pickup at the Riga collection point. We offer favorable purchase terms, including the option to split the payment into convenient monthly installments. Availability and price are updated in real time, so we recommend placing your order in advance.

### If I order this product today, when will I receive my order?

If you place your order today, delivery will be as fast and convenient as possible. You will be able to pick up your order on 01.07.2026 at the Riga pickup point or choose delivery across Latvia and Europe. We carefully inspect every purchase and pack it securely for safe transportation.

### What payment options are available?

AiO.lv offers several payment methods: Bank transfer, Bank cards on-line, Apple Pay, Google Pay, Installment. All transactions are 100% secure and encrypted.

### Can Controller TECH ST28 SIGMA for solid-fuel boilers be purchased with a lease?

Yes, the purchase is available both on credit and with an interest-free installment plan. Learn more about installments and credit options: https://aio.lv/en/payment#b3

### Can this product be purchased for a company (with VAT)?

Yes. AiO.lv works with legal entities in Latvia and across Europe. The product price already includes VAT. For certain product categories, as well as for companies from other EU countries with a valid VAT number, a 0% VAT rate may apply. We issue the invoice immediately after the order is placed, support electronic BIS invoices, and automatically generate all necessary accounting documents. You can complete the purchase for a company online — simply select the company profile and choose bank transfer as the payment method during checkout.

### What is the warranty period?

All TECH products come with an official 2 Years warranty. It covers all manufacturing defects and malfunctions that may occur during use. The warranty is valid at all authorized TECH service centers and through AiO.lv

### Can the product be returned after purchase?

Yes, you can return the product within 14 days of purchase if you bought it as a consumer (not a legal entity). Returns are possible without giving any reason — the main condition is that the product retains its original appearance and full set of accessories. We will make the process as simple and convenient as possible: just contact our customer support team, and we will help you arrange the return.

### Where should I contact for warranty service?

For warranty-related questions you can contact the AiO.lv (SIA VSPRO) customer support team. More information about warranty service: https://aio.lv/en/warranty

## Image

https://aio.lv/img/cache/product/11867798/67274173_large.webp