honeywell st7100

[irishlass]

hi

we currently have this system in place but it doesn't work. all i can do is put heating/water on either boost or contionous. cannot time either to come on and off during the day.
as this is an old system i'm looking to replace.

i was thinking the honeywell st9400. is this the correct one to replace it with? and is it easy to do? ie could my father in law who does all our diy jobs do it for me (husband is clueless) or do i need an electrician just to replace it???

hoping someone can advise. i really need a working thermostat with a newborn in the house!

thanks for you time

 

[D_Hailsham]

It may be suitable, depends on your heating system.

Do you have any motorized valves? They will look like one of these pics and are normally near your hot water cylinder.

View media item 11762 View media item 5946
If so, you can use the ST9400.

The backplate will have to be changed and the wiring is different, but your father in law should be able to cope.

The terminals are as follows:

ST7100 = ST 9400

5 = 4
7 = 1 (your system may not use this terminal)
8 = 3

L, N and E are the same!

The ST7100 is a single channel, one day programmer. This means it has the heating and hot water times are identical and the same every day of the week. The ST9400 is a dual channel, seven day programmer, which means you can have completely separate times for heating and hot water every day of the week.