Honeywell ST9400A1002 1 Day, 2-Channel, 10 W, 24 V

Product Information

Power Supply Examination: Without a detailed circuit diagram for the ST9400C, another expert suspected that the problem might lie in the power supply section of the device. The 48-volt supply, which typically involves a capacitor and diode, might be malfunctioning due to capacitor failures. Certain capacitors can lose their functionality when they remain un-polarised, leading to the deterioration of the dielectric surface. Replacing the capacitors may be a potential solution. The Honeywell ST9400A is a temperature controller designed for efficient control of heating and hot water systems. Known for its reliability and durability, this controller is a trusted choice among homeowners and professionals alike. Does this still sound like a problem with the programmer. If so, are the heat marks corresponding to the resisters and diodes a clue? Do I replace those components?

Constructed with high-quality materials, the ST9400A is built to withstand the test of time. Its robust design ensures reliable performance and long-lasting durability, minimizing the need for frequent maintenance or replacements. This makes it a cost-effective choice for homeowners looking for a reliable and efficient temperature control solution. Here's the problem: I put a nail through a pipe while refixing so loose flooring. (I know, I know). I had to shut the system off and drain it. This is probably the first time it has been off and drained since installation.All Honeywell ST9400 models incorporate the Line of Text (LoT™) display that gives clear plain English instructions whenever any button or slider is used. This means that installers, customers and users can operate all of the controls reliably, without needing to find an instruction manual. Apologies, late to this party. I have the same heat mark and warm to the touch spot on my ST9400C. This is Deja Vu for me, given my other posts on a Manrose extractor fan circuit, where a resistor is used to bring down the voltage for the timer circuit, then the heat given off by the resistor eventually blows the nearby capacitors. Another bad/cheap design driving premature failure and unnecessary electronic waste. I would say if you can no longer feel heat when placing your finger on the casing heat mark, the resistor is gone and could be replaced to fix. If the resistor is still getting hot, then a nearby capacitor has popped instead. The latter was the issue with my extractor fan, replacement capacitor fixed it.

The Honeywell ST9400A is a 2 channel programmer which is designed to control both the heating and stored hot water in a complete system, the programmes for both the heating and hot water are independent of each other to allow the system to be operated in the most energy efficient way. It looks (and feels like) the pump is running, and from what I can tell, the motorised value is still operating. The HONEYWELL ST9400A1002 1 DAY 2 CHANNEL PROGRAMMER - Now Use 4201085 is a genuine, brand new Honeywell Heating Supplies product, covered by a Honeywell Heating Supplies manufacturer's guarantee.

Honeywell ST9400A 1 Day Two Channel Programmer

Not what you're looking for? Try our unique Spares Finder tool or you can view all Honeywell Heating Supplies products. The old Danfoss 3060 I show was in this house, and I had to decide how much to spend and how far to go to improve my system, and you have the same problem, how far to go with the improvements? The Honeywell ST9400A Twin Channel Programmer unit is a 1 day full programmer with two on/off switching times per day (which can be increased to 3). The Honeywell ST6400A Programmer can be used for combi boilers, heating zones or any application where small electric loads need switching.

The ST9400A is compatible with a wide range of heating and hot water systems, making it a versatile choice for various households. Its compatibility with different system types ensures that homeowners can easily integrate it into their existing setup without any hassle.Since I got it wrong, and selected Nest Gen 3, which does not work very well, I can see your problem, but the problem only exists as I want individual room control, if I lived in a open plan house Nest would be great. Honeywell ST9400A Programmer is a 2 channel programmer, designed for control of both heating and stored hot water in complete systems. The heating and hot water programmes are completely independent, to allow the system to be operated in the most energy efficient manner possible. Replacement: A straightforward solution proposed by several experts is simply to replace the malfunctioning programmer. Given the age of the device and the persistent issues, sometimes, it’s more efficient to replace rather than repair.

Routine Maintenance: It’s essential to consider the health of the entire system. Even if the programmer is replaced or repaired, ensure that the boiler undergoes routine servicing as indicated in its manual. Neglecting regular maintenance can lead to a cascade of issues in the future. The user sought advice on potential next steps, wondering if the issue lay with the programmer or another component in the system. But this shows my point, each person will have a different situation, and what suits me as some one home 24/7 with a large house, with solar panels and oil fired central heating may not suit you. There's a problem I'm trying to troubleshoot. I have a CH/Water system with a conventional boiler, hot water cylinder, pump, 3-way motorised valve, and a gas boiler. The boiler is an Ideal Icos HE18 (18HE?). The programmer is a Honeywell ST9400C. There's also a wireless room stat for the heating, but at the moment I'm just working on getting the HW side up and running.Setting times for central heating and hot water to switch on and off can help reduce your home's energy consumption. I opened up the programmer (see pictures) and replaced the relays and large capacitor with identical value components. Relay now does not buzz (that's good), but still getting this power cycling on/off. Obviously something is still not right.