--- product_id: 48082193 title: "Honeywell Cyl Stat L641A1039" brand: "honeywell" price: "R1542" currency: ZAR in_stock: true reviews_count: 8 url: https://www.desertcart.co.za/products/48082193-honeywell-cyl-stat-l641a1039 store_origin: ZA region: South Africa --- # Snap Action SPDT Micro Switch Tamperproof Temperature Setting Easily Accessible Wiring Terminals Honeywell Cyl Stat L641A1039 **Brand:** honeywell **Price:** R1542 **Availability:** ✅ In Stock ## Summary > 🔥 Take control of your hot water like a pro—effortless, secure, and smart! ## Quick Answers - **What is this?** Honeywell Cyl Stat L641A1039 by honeywell - **How much does it cost?** R1542 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.co.za](https://www.desertcart.co.za/products/48082193-honeywell-cyl-stat-l641a1039) ## Best For - honeywell enthusiasts ## Why This Product - Trusted honeywell brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - • **Compact & Reliable:** Modern, space-saving design trusted by thousands with a 4.6-star rating. - • **Energy Smart Efficiency:** Directly switches heating pumps or valves to optimize hot water usage and reduce waste. - • **Built to Last and Secure:** Double insulated design with tamperproof settings ensures safety and durability. - • **Plug & Play Installation:** Surface mount design with easily accessible wiring terminals—install in minutes, no plumber needed. - • **Precision Control at Your Fingertips:** Manual setting knob for effortless, exact temperature adjustments. ## Overview The Honeywell L641A1039 Cylinder Thermostat is a compact, surface-mounted device designed for precise manual temperature control of domestic hot water cylinders. Featuring a snap action SPDT micro switch, tamperproof settings, and easily accessible wiring terminals, it enables quick installation and reliable operation of heating pumps or zone valves. Trusted for its durability and efficiency, this thermostat offers a modern solution to optimize your home’s hot water system while saving energy and installation costs. ## Description Product Description The L641A Cylinder Thermostat is designed for surface mounting on domestic hot water cylinders. It can be used to switch directly a wet central heating circulating pump or boiler, or to operate spring return and motor open/motor close zone valves. Box Contains 1 x L641A1039 Stat Review: Honeywell cylinder thermostat. - Easy to fit and nice and compact unit to replace old type thermostat. Works well and temperature dial easy to adjust. Review: Easy as 1-2-3 and cheaper here than local stores - Fitted in place of British Gas CS1 (which is the same as a Drayton RTS3) which was asking for hot water constantly and wouldn't switch off. Normally we only have the water programmed on for an hour a day but one day left it on by mistake and I noticed the water was insanely hot / the boiler was heating it constantly! The existing hole in my tank's insulation was wide enough although I did scrape a little extra clearance with the end of the screwdriver. I also used the existing wire band as this saved faffing around altering the one included here. After isolating the electrics, I opened up both 'stats, took a photo of the wiring in the old one and simply connected the wires to the same terminals in this unit. It was literally as easy as 1-2-3! If you can wire a plug, you can wire one of these up. The price here - approx £15 including delivery - was half the price of Screwfix / Toolstation and judging by the reviews this item is more reliable than my previous 'stat (although I suspect the old one was 10+ years old). All in all it's an easy fix. My wife tried to convince me to call a plumber. I saved a call-out, an 'hour's' labour (it took me 15 mins!) charge and no doubt a significant mark up on the item (which they may have paid £30 + for!) - so around £60 in total savings! I'll pocket the £60 to spend on more interesting things. Easy as 1-2-3. ## Features - Snap Action SPDT Micro Switch - Wiring Terminals Easily Accessible - Tamperproof Temperature Setting - Optional Manual Setting Knob Supplied - Double Insulated ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B003DTIWGO | | Backlight | No | | Best Sellers Rank | 45,603 in DIY & Tools ( See Top 100 in DIY & Tools ) 59 in Thermostats 4,950 in Electrical | | Brand Name | Honeywell | | Colour | White | | Connectivity Protocol | Wi-Fi | | Connectivity Technology | Wired and Wi-Fi | | Control Method | Touch | | Control Type | Button Control | | Controller Type | knob,manual | | Customer Reviews | 4.6 4.6 out of 5 stars (748) | | Display Type | manual | | Finish Type | Mixed | | Global Trade Identification Number | 05023220200093 | | Included Components | Cylinder Stat | | Item Type Name | Cylinder Stat | | Manufacturer | Honeywell | | Material Type | Plastic | | Model Name | Cylinder Stat | | Model Number | L641A1039 | | Mounting Type | Surface Mount | | Number of Batteries | 2 AA batteries required. | | Power Source | AC | | Product Style | Modern | | Special Features | Manual Setting Knob, Tamperproof Temperature Setting | | Specific Uses For Product | Indoor use only | | Temperature Control Type | Manual | | Unit Count | 1.0 count | | Voltage | 230 Volts | ## Product Details - **Brand:** Honeywell - **Colour:** White - **Connectivity technology:** Wired and Wi-Fi - **Controller type:** knob,manual - **Included components:** Cylinder Stat - **Model name:** Cylinder Stat - **Power source:** AC - **Special feature:** Manual Setting Knob, Tamperproof Temperature Setting - **Specific uses for product:** Indoor use only - **Temperature Control Type:** Manual ## Images ![Honeywell Cyl Stat L641A1039 - Image 1](https://m.media-amazon.com/images/I/51LnYkZr-VL.jpg) ## Questions & Answers **Q: I need a thermostat to show the tempereture of the hot water tank. It will consist of sensor wire 3 meters and an indicator to see the tempereture in** A: These units do not have a gauge attached. They are strapped on with an 'elasticated wire and make contact with the cylinder by cutting a suitable hole in the insulation. I'd think that there may well be a suitable gauge out there somewhere. I could do with one myself actually so I'll have a look on 'google' By the way I'd go for one that does not need to be powered and works on contact. **Q: why are there no screws to undo to hold the cable?** A: The unit comes with a flexible tie (same as that used for net curtains) that goes around the cylinder. This tie has hooks and the thermostat has eyes. Thus the hook and eye system keep the unit tight to the cylinder. Make are that the thermostat has metal to metal contact so that it can register the temperature of the hot water. **Q: Why does this say 2x AA batteries required, this should be mains?** A: 100% no batteries required it is hard wired into your heating / hot water junction box. **Q: I have potterton ptt2 water cylinder thermostat with sensor which is obsolete now . would this honeywell l641a1039 be ok as a replacement** A: The Potterton PTT2 is not a conventional Cylinder Thermostat as it’s wired externally to the Tank with it’s own temp sensor. Sadly as you mentioned it’s now obsolete. The only option (if you can’t find another PTT2) is to replace it with a terminal box with heat resistant flex outlet to the new stat. Up to 3 wires from the original PTT2 will need to go to the new stat, new stat instructions will confirm it. Finally the live wires will then be redundant and will require to be either terminated or spurred to a new useful output (plug socket box, a lamp etc) Please ensure a qualified electrician does ANY electrical work or changes in your home heating setup. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Honeywell cylinder thermostat. *by M***G on 28 April 2025* Easy to fit and nice and compact unit to replace old type thermostat. Works well and temperature dial easy to adjust. ### ⭐⭐⭐⭐⭐ Easy as 1-2-3 and cheaper here than local stores *by R***D on 10 November 2021* Fitted in place of British Gas CS1 (which is the same as a Drayton RTS3) which was asking for hot water constantly and wouldn't switch off. Normally we only have the water programmed on for an hour a day but one day left it on by mistake and I noticed the water was insanely hot / the boiler was heating it constantly! The existing hole in my tank's insulation was wide enough although I did scrape a little extra clearance with the end of the screwdriver. I also used the existing wire band as this saved faffing around altering the one included here. After isolating the electrics, I opened up both 'stats, took a photo of the wiring in the old one and simply connected the wires to the same terminals in this unit. It was literally as easy as 1-2-3! If you can wire a plug, you can wire one of these up. The price here - approx £15 including delivery - was half the price of Screwfix / Toolstation and judging by the reviews this item is more reliable than my previous 'stat (although I suspect the old one was 10+ years old). All in all it's an easy fix. My wife tried to convince me to call a plumber. I saved a call-out, an 'hour's' labour (it took me 15 mins!) charge and no doubt a significant mark up on the item (which they may have paid £30 + for!) - so around £60 in total savings! I'll pocket the £60 to spend on more interesting things. Easy as 1-2-3. ### ⭐⭐⭐⭐ Thermostat *by A***R on 11 May 2024* Great value. Easily fitted to tank ## Frequently Bought Together - Honeywell L641A1039 Cylinder Stat, 230 V - HONEYWELL ST9400C Thermostat Programmer. 7, 2-Channel, 3 on/Off per Day, 24 V, White, 1 - Honeywell T6360B1028 Room Thermostat, 230/240V, White, 1 --- ## Why Shop on Desertcart? - 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016 - 🌍 **Shop Globally** — Access 737+ million products across 21 categories - 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price - 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members) - 🔒 **Secure Payments** — Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.co.za/products/48082193-honeywell-cyl-stat-l641a1039](https://www.desertcart.co.za/products/48082193-honeywell-cyl-stat-l641a1039) --- *Product available on Desertcart South Africa* *Store origin: ZA* *Last updated: 2026-04-27*