"Needed to replace my 25yr old ST7100. Changed back-plate followed wiring instructions, switched back on - worked. Screwfix not cheapest but available locally. Can't tell about reliability but would like to think this controller will also last 25yrs :)"
"I reqired a controller for our local church which was versatile, easy to use and install. It replaced two timers controlling two zones and needed to be easily operated. A seven day programme was a must since Sunday is the main day. Fitting was straight forward and the large display is excellent. The override feature is very handy."
"a quality Replacement for my old, and faulty, timer/pgrammer.
clearly well buit, with sturdy casing and a good display window for easy reading in a poorly lit (under shelf) location. A well written installation note ensured no problems with replacing an older Honeywell model.
but, as always, ensure the backplate is cleaned of debris My only problem was in the poor connectivity with the contact pins as previous debris prevented a flush fit - presenting as poor power connection and a therefore a 'dead' display.
Once the backplate was cleaned, and the new unit re-presented, this problem was never seen again"
"Purchased this programmer to replace existing older version. Easy to install. You simply take off the front of the old one and place the new one on the back plate left on wall. An improvement on the old including a better, lit display. I would recommend this product."
"Only used this Programmer now for approx. one month but very pleased with it to-date. Still to use holiday programme. Great that it just fitted into existing backplate from previous Honeywell Programmer."
"I needed to replace a faulty type 721 programmer and this unit was a straight replacement.Just removed the old unit and plugged in this one no messing, even the date and time were correct, brilliant."
"I used this to replace an existing one that had only lasted a couple of years. After fitting (which was very easy due to the universal backplate) i spoke to a neighbour who told me about half the estate had had these programmers replaced. Maybe in hindsight i wouldn't have fitted it, however i can't fault it while it does work. Very good, easy to understand but fully featured. Excellent price as well."
"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...."
"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."
"Good Programmer but not having an industry standard backplate means i needed to get an electrician in to install it, this addedd to the cost. The backplate is the same but with an aditional piece to prevent you using other manufacturers in the event of failure, If i had known this i would have opted for a Drayton , Siemens, Horstmann or any other as they all use the same backplate and interchangable with no wiring changes and no need to call out an electrician....."
"Good features, easy to fit. However, reliability and quality control are not up to Honeywell standards. The first controller was defective out of the box: the display wouldn't light up. Screwfix replaced it under warranty. The second unit lasted only three years before it failed: wouldn't send power to the motorised valves. I wonder how long the third unit will last??"
"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.
"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."