---
product_id: 60963783
title: "Horstmann C21 Electronic Programmer"
brand: "horstmann"
price: "$U877"
currency: UYU
in_stock: false
reviews_count: 8
url: https://www.desertcart.uy/products/60963783-horstmann-c21-electronic-programmer
store_origin: UY
region: Uruguay
---

# 3 on/off settings 18-month battery backup Twin circuit control Horstmann C21 Electronic Programmer

**Brand:** horstmann
**Price:** $U877
**Availability:** ❌ Out of Stock

## Summary

> 🔥 Control Your Comfort, Conquer Your Costs!

## Quick Answers

- **What is this?** Horstmann C21 Electronic Programmer by horstmann
- **How much does it cost?** $U877 with free shipping
- **Is it available?** Currently out of stock
- **Where can I buy it?** [www.desertcart.uy](https://www.desertcart.uy/products/60963783-horstmann-c21-electronic-programmer)

## Best For

- horstmann enthusiasts

## Why This Product

- Trusted horstmann brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **User-Friendly Design:** Plug-in plate and 3A contacts make installation a breeze, perfect for the modern home.
- • **Effortless Scheduling:** Seamlessly manage your heating and hot water with 3 customizable on/off settings per day.
- • **Reliable Power Backup:** Stay worry-free with an 18-month battery backup ensuring your settings are preserved.
- • **Smart Energy Management:** Optimize your energy usage and reduce costs while maintaining comfort.
- • **Instant Boost Functionality:** Need a quick heat-up? Enjoy a one-hour boost for hot water or instant advance for central heating.

## Overview

The Horstmann C21 Programmer is a sophisticated twin circuit electronic programmer designed for efficient management of heating and hot water systems. With three customizable on/off settings for both hot water and central heating, an instant boost feature, and an impressive 18-month battery backup, this device ensures you stay in control of your home environment effortlessly.

## Description

Competitively priced electronic timeswitches and programmers with back lit display, automatic BST/GMT clock change and 6 pin wall plate. Controls most domestic gas or oil-fired central heating and hot water systems.

Review: Well made Control Switch - This worked perfectly, it was easy to set up. easy to read display. Bear in mind the switching timer is in 10 minute segments, which isnt a problem, it only makes things easier to change a time. One big advantage is you can set the HW and CH independently. you don't always want the heating on at the same time in the day as the hot water. I also have found the clock to be very accurate and has a date setting too. and the biggie is a 3amp switching which means I can use one of these controllers for a completely different purpose. lovely product.
Review: Excellent - Bought this to replace a C21 unit which had developed a fault. New unit slotted straight into existing contacts plate and worked perfectly.

## Features

- Twin circuit electronic programmer
- 3 on and off settings for HW and 3 on and off settings for CH per day
- One hour boost HW (only) and instant advance for CH (only)
- 18 months battery back up
- 3A contacts, plug-in plate

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00CZA8NGQ |
| Batteries Required? | No |
| Batteries included? | No |
| Customer Reviews | 4.2 4.2 out of 5 stars (14) |
| Date First Available | 24 May 2013 |
| Item Package Quantity | 1 |
| Item Weight | 340 g |
| Item dimensions L x W x H | 18 x 14.6 x 6.2 centimetres |
| Item model number | C21 |
| Manufacturer | Horstmann |
| Part Number | C21 |
| Product Dimensions | 18 x 14.6 x 6.2 cm; 339.99 g |
| Wattage | 3 watts |

## Product Details

- **Brand:** Horstmann
- **Colour:** Multi
- **Included components:** 05015914196027
- **Mounting type:** Wall Mount
- **Power source:** Battery Powered

## Images

![Horstmann C21 Electronic Programmer - Image 1](https://m.media-amazon.com/images/I/71CWoRgIBHL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Well made Control Switch
*by S***4 on 23 May 2014*

This worked perfectly, it was easy to set up. easy to read display. Bear in mind the switching timer is in 10 minute segments, which isnt a problem, it only makes things easier to change a time. One big advantage is you can set the HW and CH independently. you don't always want the heating on at the same time in the day as the hot water. I also have found the clock to be very accurate and has a date setting too. and the biggie is a 3amp switching which means I can use one of these controllers for a completely different purpose. lovely product.

### ⭐⭐⭐⭐⭐ Excellent
*by R***Y on 22 November 2019*

Bought this to replace a C21 unit which had developed a fault. New unit slotted straight into existing contacts plate and worked perfectly.

### ⭐⭐⭐⭐⭐ A great programmer
*by J***S on 10 February 2019*

This programmer replaced an old electro-mechanical programmer. The clock had stopped working after over thirty years so fitted this new one. It simply fitted onto the original single patress box and then wired as before taking into account the simple instructions provided. Job done and looks good.

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*Product available on Desertcart Uruguay*
*Store origin: UY*
*Last updated: 2026-05-18*