i cant get my plumber in till monday so thought i would ask on here,fitted new bathroom 2 months ago and am now getting no hot water out the shower and very limited supply from the taps.

my plumber came in yesterday to move a radiator in the kitchen,the pipes and valves are in the correct place but radiator not fitted yet,i think he said he drained the system to do this.

its an old house and hasnt got a combi boiler yet just a backboiler and tank upstairs(i think this is the case i'm not too clued up on plumbing!)

what could be the problem with the lack of hot water to the shower especially but also the taps to a certain extent???