Hot water in shower not working but taps in sink fine

[Richy]

hi all
I have an issue with the hot water in my shower that you can hopefully help me with.
Back story
I recently drained my system in attempt to clear what I thought was sludge in the radiators ( another story ) after I filled the system back up I can’t get constant hot water in the shower , it’s Luke warm but not boiling . Before I could only turn it up three quarters before it got too hot .
On random occasions it will get very hot but not for long .
Taps in the sink ten feet away are piping hot the water in the bath taps get hot but only if you don’t turn the tap on too much .
The shower worked fine before the system was drained but now it’s gubbed
Any advice would be greatly appreciated
It’s a Wooster boiler about 5 years old
Cheers
Richy

 

[ShaunCorbs]

Have you tried removing the shower if it's a bar type and having someone hold a bucket in front to check your getting hot water and it's definitely the shower ?

 

[Richy]

Have you tried removing the shower if it's a bar type and having someone hold a bucket in front to check your getting hot water and it's definitely the shower ?

The shower is getting hot water as it goes very hot on occasions ,
I feel it’s got something to do with the water pressure in the boiler possibly not enough to trip the boiler properly
It worked fine until the system was drained

 

[ShaunCorbs]

Won't be the pressure but it could be the flow

With the shower running open a hot tap in the basin does the shower get warm ?