Honeywell ST9400C Programmer

Product Code: 88608
Honeywell ST9400C Programmer
Product Code: 88608
Separate timing. 2-wire installation. Override facility. Holiday mode. Automatic BST/GMT time change. Boost function. Building Regulations compliant, WEEE, RoHS.


  • 7 Day Programmable
  • 1, 2, or 3 On/Off Periods per Day
  • Digital Display
  • Suitable for Gravity-Fed & Fully Pumped Systems
  • 3 Pre-Set Programmes
  • 2 Wire Installation
  • Backlit Display
  • Battery Back-Up


Switching/contact rating: SPDT 3(3)A. H x W x D: 99 x 145 x 35mm. Backplate fit: Industry Standard. Suitable for underfloor heating.

Was €111.95

Special Price €99.95

Incl. 20% VAT

Save €12.00 (10%)

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Additional Information
Technical Specification
  • Brand : Honeywell
  • Manufacturing Standards : Building Regulations Compliant, CE, WEEE, RoHS
  • Product Height : 99 mm
  • Display Type : Digital Display
  • Product Type : Programmer
  • Programme Facility : 7 Day Programmable
  • Model No : ST9400C
  • Product Width : 145 mm
  • Product Depth : 35 mm
  • Pack Size : 1
  • Switch Type : SPDT
  • Suitable System : Suitable for Gravity-Fed & Pumped Systems
  • Installation Type : 2-Wire Installation
  • Manufacturer Guarantee : 1 Year Manufacturer's Guarantee
  • Pieces in Pack/Case : 1
Product Contents
1 off ST9400C 2 channel heating programmer
Delivery & Returns


Standard delivery: €15

Free delivery on all orders over €70.00

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Hopefully you won't need to return an item, however, if you do, it is our aim to make this as simple as possible. By following the guidance below you can help us to help you when a product is not what you expected, or is faulty. Your statutory rights are not affected by this guidance.


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Honeywell ST9400C Programmer is rated 3.4 out of 5 by 63.
Rated 5 out of 5 by from All good Firstly I've only had this item a couple of days so the reliability score is, ironically, not that reliable but hopefully it will be accurate. It was purchased to replace a second Drayton LP722 programmer which failed within 6 months, the previous one only lasting 2 years. Hopefully this one will have a longer lifespan. Mounting plate compatible with the Drayton so it was an easy remove and replace, no wiring to be done. Honeywell provide a compatability chart on their website too so you can check. The programmer has plenty of functions and features like boost times and holiday modes and it was a doddle to set up. It seems well built and worked straight out of the box.
Date published: 2016-11-01
Rated 1 out of 5 by from Built-in unreliability. Had one of these fitted 2 years ago, and we've just had to replace it. As other reviewers have said, it's about the most expensive controller in the Screwfix book and it seems like it's designed to pack up after a couple of years. The lights come on, but it doesn't tell the boiler to start up. Keep pressing buttons and it may work, or may not. Had to buy another unfortunately, a) to prove the first one had packed up, and b) to avoid the cost of an electrician to fit another type. Don't do it, look by all means then move on to a cheaper product. Had to give it one star for reliability because there isn't a "no star" option.
Date published: 2016-10-11
Rated 3 out of 5 by from IGuy Good Product but does not piggyback on to Potterton ep programmers as some sites say it does. Only Potterton EP2 does this so that the Back plate with its wiring needn't be rewired. Great for DIY'ers no need for an electrician. Very quick procedure (less than 5 minutes)
Date published: 2016-07-28
Rated 5 out of 5 by from Honeywell done it again Bank Holiday weekend and a return client needed hot water and heating asap - thankfully Screwfix had the item in stock - job done within the hour. Honeywell programmer is easy to use and set - always use this product if possible.
Date published: 2016-05-02
Rated 5 out of 5 by from Good Programmer Old unit went down typically when it was cold weather. Picked new unit up locally and fitted it. Up and running within 30 mins from start to finish.. Fitted onto old backplate, bonus, programming easy.
Date published: 2016-04-27
Rated 4 out of 5 by from In control Brought as a direct replacement to another which had failed in auto mode, CH not coming ON as programmed, HW all OK. After manual over ride all is well again? One of the problems I find with all electronic devises is that there is little you do beside replacement.......built in obsolescence! This is a good product with a fairly straight forward set up / programming, end user in this case likes the features.
Date published: 2016-01-16
Rated 5 out of 5 by from Honeywell ST9400C programmer My ST6400C programmer failed whilst on holiday. Bought this product (replacement model) and all I had to do was plug it straight onto the original backplate with no need to rewire. This then ensured that all other thermostat controls in the house continued to work.
Date published: 2016-01-01
Rated 1 out of 5 by from Poor quality device My experience is just as bad as the other reviewers have found. These devices would be excellent if they didn’t break down so often. I’d give 5 stars for features if the device would work long enough to make use of them. I had some good help in diagnosing the fault from Honeywell support people, but when I asked if they would offer an extended warranty on a new one, in view of the track record, I got no reply. Not really surprised that they ignored me. But I am surprised that any supplier would go on selling them. Do NOT waste your time on this poor quality device.
Date published: 2015-12-17
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