Water not heating up beyond 55 degrees

[Sbrennan]

Hi All,
I have set the hot water on my Evohome controller to 60 degrees but it doesn't seem to heat beyond 55. I have turned it on for 3-4 hours and it still won't heat above 55. Is there anything I should be checking before I call a plumber?
Thanks!

[Somebody]

Have you turned the original analogue thermostat on the hot water tank to max? It may be restricted by the original thermostat.