Honeywell ST699

Product Information

Early batteries were removable and Varta make a replacement for about a fiver. You could try Maplin among other suppliers. Just think what if your away for a while in the winter and it was like last year and the power goes off. For 5mins work and 5 quid could save you loads of hassle.

It is unlikely to be a battery problem. If yours was a later model with a reset button, press that. If not, power off for 30 minutes. When it didn't work, I've Googled again and come across this Forum. Whilst I can find a few issues other users have had, I can't find anything that relates to my issue. I have noticed however, that the old wiring to the ST699 that is redundant, wasn't as per the diagram I saw in one of the posts. I have cables linking: If only 3 & 8 were originally connected as per pdf .... For a gravity HW system, the hot water coming on fires up the boiler and the central heating being on powers the pump. To get you up and running should require the following links on the ST9400C

Honeywell ST699: Frequently viewed Manuals

Yes, the picture of the ST699 is now - those are the linking cables left in after removing the other cables. Is it as simple as looking at a wiring diagram for the ST699 and attaching to the corresponding connection of a new timer? Yep like that - they're called 'Lifestyle 2-port motorised valve', there is one underneath the pump on a pipe that doesn't go into the cylinder, and one on a pipe that come off the other pipe and goes into the cylinder about halfway up it. Using "ST9400c Wiring 1.jpg" going left to right can you indicate which core went into which connection on the ST699

If you have a S-Plan system with a single heating zone 3 for HW-On and 4 for CH-On, nothing to either 1 or 2. You have what they call BASIC SYSTEM 1 or 2. Gravity hot water, pumped CH and with/without room thermostat. Now just need to see how that maps to the ST9400. However you should ensure you know what went where on the ST699. The use of three blue cores, two brown cores and one red core coming into the ST699 is a recipe for confusion. Strangely enough the links between terminals is the least of the problems. I've attached pics of the ST9400C wiring before and after the swap (ST9400c Wiring 1) and a pic of the remaining wires in the ST699. Unfortunately wiring colours tend to be meaningless with heating systems. One installer may use a blue wire for a certain purpose another may use a brown for the same function. So never assume a blue wire is actually being used as a neutral it may be being used as a live. It's what a wire is connected to at each end that determines its function, not the colour of its insulation.They've both got what looks like a switch with A - B settings, the one on the pipe running down past the cylinder is set to B, and the one on the pipe running into the cylinder is set to A, someone has also written on this one with a marker pen putting a C next to the A and an O next to the B (presumably meaning open and closed?). I'd recommend you tidy the wires a bit. The number of loose strands is a disaster waiting to happen.