{"product_id":"totalhome-tth2ct-2-channel-7-day-programmer-replaces-honeywell-st9400c-st9400a-st712","title":"Totalhome TTH2CT 2 Channel 7 Day Programmer - Replaces Honeywell ST9400C ST9400A ST712","description":"\u003cdiv style=\"font-size:16px; font-family:Arial,sans-serif; color:#222; max-width:900px; margin:0 auto; line-height:1.6;\"\u003e\n\n  \u003cp style=\"margin:0 0 18px;\"\u003eThe \u003cstrong\u003eTotalhome TTH2CT\u003c\/strong\u003e is a \u003cstrong\u003etwin-channel, 7-day full programmer\u003c\/strong\u003e designed for \u003cstrong\u003eindependent control of central heating and stored hot water\u003c\/strong\u003e. Manufactured by Resideo — the engineering team behind the Honeywell Home range — the TTH2CT is the \u003cstrong\u003edirect replacement for the Honeywell ST9400C\u003c\/strong\u003e and is also compatible as a swap-out for the ST9400A, ST712A, ST722A, ST772, C21, C27, ST6300A, ST6200A, ST6400A, ST6450B, and THR860SWE. It \u003cstrong\u003efits the industry-standard backplate\u003c\/strong\u003e, so changeover requires no new wiring. With a \u003cstrong\u003elarge backlit text display\u003c\/strong\u003e, \u003cstrong\u003e3 on\/off periods per day\u003c\/strong\u003e per channel, \u003cstrong\u003eholiday mode\u003c\/strong\u003e, automatic summer\/winter clock change, and a \u003cstrong\u003e3-year warranty\u003c\/strong\u003e, it is a reliable and cost-effective upgrade for any S-plan, Y-plan, or combination heating system.\u003c\/p\u003e\n\n  \u003c!-- Stat strip --\u003e\n  \u003cdiv style=\"display:flex; flex-wrap:wrap; gap:12px; margin:0 0 24px;\"\u003e\n    \u003cdiv style=\"flex:1; min-width:120px; background:#008377CF; color:#fff; border-radius:8px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:20px; font-weight:700;\"\u003e2 Channel\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px;\"\u003eHeating + Hot Water\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:120px; background:#008377CF; color:#fff; border-radius:8px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:20px; font-weight:700;\"\u003e7-Day\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px;\"\u003eIndependent Schedules\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:120px; background:#008377CF; color:#fff; border-radius:8px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:20px; font-weight:700;\"\u003e3 Periods\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px;\"\u003ePer Day Per Channel\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:120px; background:#008377CF; color:#fff; border-radius:8px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:20px; font-weight:700;\"\u003eHoliday\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px;\"\u003eMode Included\u003c\/div\u003e\n    \u003c\/div\u003e\n    \u003cdiv style=\"flex:1; min-width:120px; background:#008377CF; color:#fff; border-radius:8px; padding:14px 10px; text-align:center;\"\u003e\n      \u003cdiv style=\"font-size:20px; font-weight:700;\"\u003e3 Years\u003c\/div\u003e\n      \u003cdiv style=\"font-size:12px; margin-top:4px;\"\u003eWarranty\u003c\/div\u003e\n    \u003c\/div\u003e\n  \u003c\/div\u003e\n\n  \u003c!-- Red: installer note --\u003e\n  \u003cdiv style=\"background:#fff5f5; border-left:4px solid #c0392b; border-radius:6px; padding:14px 16px; margin:0 0 16px;\"\u003e\n    \u003cstrong style=\"color:#c0392b;\"\u003e⚠ Installer Notice\u003c\/strong\u003e\u003cbr\u003e\n    The TTH2CT operates at \u003cstrong\u003e230 V AC mains voltage\u003c\/strong\u003e and must be installed by a \u003cstrong\u003ecompetent person\u003c\/strong\u003e. Isolate the circuit and prove dead before accessing the backplate or terminals. All wiring must comply with the current IET Wiring Regulations (BS 7671).\n  \u003c\/div\u003e\n\n  \u003c!-- Teal: what's in the box --\u003e\n  \u003cdiv style=\"background:#e6f4f3; border-left:4px solid #008377; border-radius:6px; padding:14px 16px; margin:0 0 24px;\"\u003e\n    \u003cstrong style=\"color:#005c54;\"\u003eⓘ What's in the Box\u003c\/strong\u003e\u003cbr\u003e\n    1 × TTH2CT 2-channel programmer  |  1 × New industry-standard backplate  |  Installation and user guide\n  \u003c\/div\u003e\n\n  \u003c!-- Feature cards --\u003e\n  \u003cdiv style=\"background:#008377CF; color:#fff; padding:10px 16px; border-radius:6px 6px 0 0; font-weight:700; font-size:15px; margin-bottom:0;\"\u003eKey Features\u003c\/div\u003e\n  \u003cdiv style=\"display:grid; grid-template-columns:repeat(auto-fit,minmax(250px,1fr)); gap:14px; background:#e6f4f3; border:1px solid #c8e6e3; border-top:none; border-radius:0 0 6px 6px; padding:16px; margin:0 0 28px;\"\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003eIndependent Dual-Channel Control\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eThe TTH2CT gives \u003cstrong\u003ecompletely independent scheduling for heating and hot water\u003c\/strong\u003e. This means the hot water can be programmed to come on earlier in the morning than the heating, or remain on longer in the evening — maximising energy efficiency and ensuring the system is \u003cstrong\u003enever running either channel unnecessarily\u003c\/strong\u003e.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003eLarge Backlit Text Display\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eUnlike older programmers with icon-only displays, the TTH2CT features a \u003cstrong\u003elarge backlit display with a line of plain text feedback\u003c\/strong\u003e. The screen clearly shows the current day, time, operating mode, and active channel status — making it simple for any household member to read and operate without guesswork.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003e3 On\/Off Periods Per Day\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eEach channel supports \u003cstrong\u003eup to 3 programmable on\/off switching times per day\u003c\/strong\u003e, giving sufficient flexibility for most household routines — including morning, lunchtime, and evening heating or hot water periods. Programme indicator lights show at a glance which channels are currently active.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003eHoliday Mode\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eThe dedicated \u003cstrong\u003eHoliday button overrides the normal programme\u003c\/strong\u003e for a set period while you are away. Both channels switch off (or to a minimal setback) until the holiday period ends, at which point the programmer automatically resumes the regular schedule — \u003cstrong\u003eno need to remember to reprogram on your return\u003c\/strong\u003e.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003eAuto Summer\/Winter Time Change\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eThe TTH2CT \u003cstrong\u003eautomatically adjusts for British Summer Time (BST) and Greenwich Mean Time (GMT) transitions\u003c\/strong\u003e — the clock moves forward or back by one hour at the correct moment without any manual intervention. The \u003cstrong\u003eExtra Hour function\u003c\/strong\u003e allows a one-hour manual shift at any time if needed.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n    \u003cdiv style=\"background:#f0faf9; border:1px solid #c8e6e3; border-radius:6px; padding:16px;\"\u003e\n      \u003cdiv style=\"font-weight:700; color:#008377; border-bottom:2px solid #008377; padding-bottom:6px; margin-bottom:10px;\"\u003eIndustry-Standard Backplate — Easy Upgrade\u003c\/div\u003e\n      \u003cp style=\"margin:0; font-size:14px;\"\u003eThe TTH2CT fits the \u003cstrong\u003estandard Honeywell\/industry-standard wiring centre backplate\u003c\/strong\u003e, meaning it can replace the ST9400C, ST9400A, ST712A, ST722A, C21, C27, ST6300A, ST6200A, ST6400A, ST6450B, and THR860SWE with \u003cstrong\u003eno rewiring required\u003c\/strong\u003e. A new backplate is included for fresh installations.\u003c\/p\u003e\n    \u003c\/div\u003e\n\n  \u003c\/div\u003e\n\n  \u003c!-- Spec table --\u003e\n  \u003cdiv style=\"background:#008377CF; color:#fff; padding:10px 16px; border-radius:6px 6px 0 0; font-weight:700; font-size:15px;\"\u003eTechnical Specifications\u003c\/div\u003e\n  \u003ctable style=\"width:100%; border-collapse:collapse; margin:0 0 28px; font-size:14px;\"\u003e\n    \u003ctbody\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; width:42%; border-bottom:1px solid #c8e6e3;\"\u003eManufacturer Part Number\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eTTH2CT\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eChannels\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003e2 (heating + hot water — fully independent)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eProgramming\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003e7-day, up to 3 on\/off periods per day per channel\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003ePower Supply\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003e230 V AC mains\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eDimensions (H × W × D)\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003e95 mm × 152 mm × 42 mm\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eDisplay\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eLarge backlit display with text feedback\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eOverride Functions\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eTemporary, permanent, Extra Hour, Holiday mode\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eAuto Clock Change\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eYes — automatic BST\/GMT (summer\/winter)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eMounting\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eIndustry-standard backplate (new backplate included)\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eDirect Replacement For\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003eHoneywell ST9400C, ST9400A, ST712A, ST722A, ST772, C21, C27, ST6300A, ST6200A, ST6400A, ST6450B, THR860SWE\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#f0faf9;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600; border-bottom:1px solid #c8e6e3;\"\u003eWarranty\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px; border-bottom:1px solid #c8e6e3;\"\u003e3 years\u003c\/td\u003e\n\u003c\/tr\u003e\n      \u003ctr style=\"background:#fff;\"\u003e\n\u003ctd style=\"padding:9px 12px; font-weight:600;\"\u003eManufacturer\u003c\/td\u003e\n\u003ctd style=\"padding:9px 12px;\"\u003eResideo (TotalHome)\u003c\/td\u003e\n\u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\n  \u003c!-- FAQ --\u003e\n  \u003cdiv style=\"background:#008377CF; color:#fff; padding:10px 16px; border-radius:6px 6px 0 0; font-weight:700; font-size:15px;\"\u003eFrequently Asked Questions\u003c\/div\u003e\n  \u003cdiv style=\"border:1px solid #c8e6e3; border-top:none; border-radius:0 0 6px 6px; margin:0 0 28px; overflow:hidden;\"\u003e\n\n    \u003cdetails style=\"border-bottom:1px solid #c8e6e3;\"\u003e\n      \u003csummary style=\"background:#e6f4f3; padding:12px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eWhat is the difference between a 1-channel and a 2-channel programmer?\u003c\/summary\u003e\n      \u003cdiv style=\"padding:12px 16px; font-size:14px;\"\u003eA \u003cstrong\u003e1-channel programmer\u003c\/strong\u003e (such as the TTH1CT) controls only heating — hot water is either always on, always off, or follows the same schedule as the heating. A \u003cstrong\u003e2-channel programmer\u003c\/strong\u003e like the TTH2CT controls heating and hot water \u003cstrong\u003eon completely independent timed schedules\u003c\/strong\u003e. This is essential for homes with a \u003cstrong\u003eseparate hot water cylinder\u003c\/strong\u003e (such as S-plan or Y-plan systems) where hot water demand does not mirror the heating schedule.\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails style=\"border-bottom:1px solid #c8e6e3;\"\u003e\n      \u003csummary style=\"background:#e6f4f3; padding:12px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eWill the TTH2CT fit my existing Honeywell ST9400C backplate?\u003c\/summary\u003e\n      \u003cdiv style=\"padding:12px 16px; font-size:14px;\"\u003eYes. The TTH2CT uses the \u003cstrong\u003esame industry-standard backplate\u003c\/strong\u003e as the ST9400C and a wide range of other Honeywell programmers. In most cases the wiring can remain exactly as it is — just remove the old programmer from the backplate and clip the TTH2CT in place. A new backplate is included in the box if a fresh installation is needed.\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails style=\"border-bottom:1px solid #c8e6e3;\"\u003e\n      \u003csummary style=\"background:#e6f4f3; padding:12px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eHow does the Holiday mode work?\u003c\/summary\u003e\n      \u003cdiv style=\"padding:12px 16px; font-size:14px;\"\u003ePress the \u003cstrong\u003eHoliday button\u003c\/strong\u003e and set the number of days you will be away. Both the heating and hot water channels are suppressed for the duration, saving energy while the property is empty. When the holiday period expires, the programmer \u003cstrong\u003eautomatically returns to the normal 7-day schedule\u003c\/strong\u003e — no need to reprogram or manually re-enable it on your return.\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails style=\"border-bottom:1px solid #c8e6e3;\"\u003e\n      \u003csummary style=\"background:#e6f4f3; padding:12px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eCan I give the hot water an extra hour without changing the whole programme?\u003c\/summary\u003e\n      \u003cdiv style=\"padding:12px 16px; font-size:14px;\"\u003eYes. The \u003cstrong\u003eExtra Hour function\u003c\/strong\u003e extends the current active period for the relevant channel by one hour — without altering the underlying programme. It is ideal for moments when someone needs a shower outside the normal schedule or wants to extend the heating on a particularly cold evening. The programme resumes as normal after the extra hour.\u003c\/div\u003e\n    \u003c\/details\u003e\n\n    \u003cdetails\u003e\n      \u003csummary style=\"background:#e6f4f3; padding:12px 16px; font-weight:600; cursor:pointer; list-style:none;\"\u003eDo I need to manually adjust the clock for daylight saving time?\u003c\/summary\u003e\n      \u003cdiv style=\"padding:12px 16px; font-size:14px;\"\u003eNo. The TTH2CT includes an \u003cstrong\u003eautomatic summer\/winter clock change\u003c\/strong\u003e that advances the clock by one hour in spring and reverts in autumn in line with UK BST\/GMT transitions. No manual adjustment is needed. The \u003cstrong\u003eExtra Hour button\u003c\/strong\u003e is available if you ever need to apply a one-hour shift manually outside of the automatic change.\u003c\/div\u003e\n    \u003c\/details\u003e\n\n  \u003c\/div\u003e\n\n\u003c\/div\u003e","brand":"Totalhome by Resideo","offers":[{"title":"Default Title","offer_id":64672003457373,"sku":"TTH2CT","price":49.0,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0958\/2051\/3629\/files\/Totalhome2Channel7DayProgrammertth2ct.webp?v=1778598405","url":"https:\/\/qualityheating.co.uk\/products\/totalhome-tth2ct-2-channel-7-day-programmer-replaces-honeywell-st9400c-st9400a-st712","provider":"AIZO Quality Heating","version":"1.0","type":"link"}