Honeywell ST6400C Playing Up

I got asked to look at a Honeywell ST6400C programmer which had been playing up recently. This programmer is a two-channel programmer with lights for both heating and hot water. The programmer had been set to come on automatically for heating and water and various time throughout the day. However, the heating had not always been coming on or going off at the times. The heating light was coming on and off, but not in line with the times set.

I decided to replace the programmer, and used a Danfoss Randall FP715 Si programmer. Using the industry standard backplate makes it simple to replace many programmers, and future replacement of the programmer itself. A permanent backlit display is also handy for the 'darker' installations. Automatic summer/winter time change also is a useful feature.

The programmer can be set up in a variety of ways to suit the end user, the time can be set to be displayed as AM/PM or 24 hour time-clock. The programmes can be configured to provide either 2 or 3 on/off settings. The programmer can also be set for a fully-pumped or gravity system. For the installer the biggest benefit is the ability to configure it either as a 24 hour, 5/2 day or 7 day programmer as the customer desires. This programmer genuinely suits the majority of installations and is currently one of my favoured programmers to be kept as van stock.

Disclaimer: The works described in this blog are a record of work undertaken and should not be taken as guaranteed to solve your problem. Work should only be carried out by persons qualified and competent to do so.