Horstmann 425TIARA Programmer, Black

Product Information

One number makes a huge difference, as my system only has two "channels" - hot water and central heating. I can get a screwdriver between the wall box and the stand-off but there's no way they are going to separate without my breaking one of them. No more damage to anything although I did need to fill and strengthen the partitioning wall around where my previous attempts had ruined the structure. It has 16 programmes available for fully pumped systems, including independent programming of heating and hot water as well as 10 programmes for gravity hot water/pumped heating systems.

i just would like to be able to programme at least 3 times aday and what exactly does using the existing backplate mean. Full of plastic works though and not like the old brass works similar to the works of old house clocks. I wonder if it's simply that the wiring box isn't firmly fixed, so is moving and not allowing the programmer to "snap" away from the backplate.I'd prefer not to break it as a replacement is some 90 quid, not to mention the loss of any hot water for the days it takes to turn up. I did it now - i thought that the outer plastic frame was already a backplate and that what got me confused. The HORSTMANN (SECURE) 425 TIARA PROGRAMMER - Now use 4210051 or 4210056 is a genuine, brand new Horstmann Controls product, covered by a Horstmann Controls manufacturer's guarantee. The main issue here is to ensure a safe method of separating the hot water and central heating cycles with a primatic hot water cylinder. Another option if you do bugger it would be a single channel timer in it's place to run the hot water, then control the two heating circuits from prog room stats on each floor if possible.

But I think a modern electronic clock that has options to choose exact on/off settings and 1, 2 or 3 hour on cycles, is best. The Tiara is ideally suited for both gravity systems and fully pumped systems with either zone or mid-position valves. Having checked thousands of central heating control reviews, we can say that the Horstmann is the best choice for most people.

The list should not be considered a complete list of all available, excellent central heating controls.

A one or two channel programmer should use the same terminals, a 3 channel programmer may need some adjustment to the wiring. This was supposed to be a direct replacement, simply clipping onto the identical backplate and giving me new functionality, with the ability to set different times for different days. The term should really be used only for systems where the circulation through the HW coil is due to the change in density of the water when heated; i.Fitted new one and was slightly irked that the LCD screen on the new one is damaged - faded in places making it hard to read. Our 425 series of mechanical programmers are the simplest way to control hot water and central heating in the home. Offers 16 programmes for fully pumped systems incorporating motorised or mid-position valves and 10 programmes for gravity H. The whole idea is that the expansion of the hot water in the radiator / boiler pipework is taken up by an air pocket in the primatic hot water cylinder. Turned off the leccy, stuck a "bladed" lever into the top (it's a wide pry-bar I'd previously ground to a flat edge) and woofed it off the wall.