March Tails_Blooms_N_Anything, page-76

That's exactly how I have been managing it - go into the laundry where the unit is located - turn cold water tap on ever so lightly, then slowly turn hot tap until an audible click is heard, let it get hot - run into the bathroom and gently do the same, once the hot water comes out of bathtub tap - go back into laundry and turn tap off. 
A bit hard to do when visitors are trying to take a shower . . . .  and you have to explain or do the laundry-bathroom dance for them, while they're waiting to take a shower.

But will get a service done, as it states on the side it should be checked every 4 months or so, because water deposits can clog inside works - I never gave this a thought.
... and it was installed in 2012 - so not bad going. thanks again -
Tau