Siemens RAA20 Replacement Thermostat Not Working

[tigers999]

Evening all,

A couple of weeks ago our room thermostat stopped working. Long story short I bought an exact replacement, a Siemens RAA20. I wired it up and off it went working fantastic. Its only been on a week but its stopped working already grr?!

We live in a 3 storey house with a barely adequate boiler (thanks barratts) Its an ICOS HE12 with a siemens controller which tbh we dont use because im at home most of the days so the heating is on pretty constant throughout winter. The boiler is 7 years old and has had work done on it but the boiler man explained last time that we really could do with a better model but its the £1K plus thats the problem lol

Anyway my point, any ideas what could be wrong with the thermostat? Have I just been unlucky and another thermostat has gone or shall I ring the boiler man for what could be a bigger problem?

The hot water is working fine and once you run the hot tap for abit the boiler kicks in meaning the heating starts to work too. The only problem is, we cant turn the heating off or down because the thermostat wont kick in again grrr (hope you understood that lol).

One last thing just to confirm its correct, itss wired up as follows - 2 wires, black and a brown. 3 connectors in the thermostat, L1 Y1 and Y2. I have the Brown in L1 and the Black in Y1? I think its right but you never know lol

Thanks in advance for any help

 

[tigers999]

Edit - hmmm might be working lol sorry

 

[D_Hailsham]

First of all you have to prove that the thermostat is faulty.

Turn CH off at timer
Turn power off
Remove thermostat from the wall

Use a short length of wire to join terminals L and Y1 on the wall plate

Turn power on
Turn CH on at timer.

Boiler should run continuously until turned off by timer. (Boiler stat may turn off first.)

If it doesn't: wire from stat to boiler is faulty OR boiler is faulty.

If it does: thermostat is faulty