Honeywell ST9400C Programmer
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.
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
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