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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
  • View more information

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.

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Honeywell ST9400C Programmer Instruction Manual


3.1429 5 28

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Honeywell ST9400C Programmer 3.1 5 28 28
Very unreliable programmer The Honeywell ST9400C has perfect looks, a lovely light blue large backlit display, a massive array of features such as up to 3 hour boost function and holiday hold off. But....it's very unreliable. Without warning it WILL fail. I've now replaced two units in just under three years. Neither unit made it to eighteen months old. The fault on both occasions appears to be the internal relays fail in a weird manor. Only one circuit will switch on, either H/W or C/H but not both. The display will show them both on if both have been selected but only one circuit will be powered. Avoid. 4 Mar 2015
Dodgy unit? or not good? BAD - Unit stopped working just 2 years after installation. Expensive product that should last a lot longer than this. GOOD - Has lots of features including automatic update of GST/BST hour changes which is very useful and gives peace of mind. Worked great while it did. Surely it could be cheaper though.... 2 Feb 2015
Honeywell Programmer Seems like a great product marred by poor reliability. This is my third: first lasted two years; second lasted three months; jury still out on third one. But excellent customer service from Screwfix - item collected and installed less than 50 minutes after ordering on line! And their website is a doddle to use. 19 Jan 2015
ST9400C is prone to failure I had a new central heating system fitted four years back and had an ST9400C unit fitted as part of this, it failed in Oct 2014. My plumber fitted a replacement ST9400C unit, after less than two months it has failed. The programmer turns the central heating on randomly and it turns the central heating on when you have programmed it to generate hot water. I now have the hassel of getting this replaced again, thanks Honeywell. My Father had a similar unit installed three years ago, his failed last month. I think Honeywell are selling this shoddy products at premium prices, I will not be using them again. I'm so annoyed about this that I took the trouble to register with screwfix in order to warn people. 18 Dec 2014
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Download more info (pdf)

Brand Honeywell
Colour White
Display Type Digital Display
Installation Type 2-Wire Installation
Manufacturer Guarantee 1 years
Manufacturing Standards Building Regulations Compliant, CE, WEEE, RoHS
Model No ST9400C
Pack Size 1
Product Depth 35 mm
Product Height 99 mm
Product Length 145 mm
Product Type Programmer
Product Width 145 mm
Programme Facility 7 Day Programmable
Suitable System Suitable for Gravity-Fed & Pumped Systems
Switch Type SPDT
Total Product Weight 0.27 kg