4 wires in room stat

[okneedhelpplease]

I have used this site before an thanks to all who helped, but now my mums heating was playing up. She has a none combi boiler on a danfoss mech timer, i change the pump but it was the room stat that keps blowing the 3amp fuses. so i bourght a danfoss RMT230. The problem is the ol stat has 4 wires but the instructions on the new one only is showing 3.
The ol on has a red, green, yellow & blue. All i no is that the yellow goees to the pump an the red is live? can anyone help.

 

[seco services]

more likely the earth not needed.

 

[okneedhelpplease]

is this common on this stat. an thanks for the lightning sped reply

 

[seco services]

yes now days

 

[okneedhelpplease]

i will try this now ----- thankyou i will let you no