3 port valve - Pipe Sizes

[andrew5235]

I have a vented fully pumped system, using a 3 port divertor valve, there seems to be plenty of heat in the pipe going to the hot water tank (120L tank) and the radiators are very hot to touch. However the hot water takes 2 hours or more to heat from cold, I don't think that this is how it should be.

I am wondering if there is something wrong with the set-up, it is 22mm to the divertor and going to the radiators, but the hot water tank feed and return are 15mm. Is this correct and does this provide enough flow? What else could cause the tank to take so long to heat up.

Thanks
Andrew

 

[gavinda]

its not ideal, but perfectly normal to see this. but it is a lot easier for it to get blocked. check the flow and returns with a magnet.

 

[andrew5235]

Should I be checking along with full length of both? I recently replaced the 3 port valve and the inside of the flow pipe at that end was coated with sludge. Could it just be a narrowing of the pipe, because the whole length is coated in the sludge?

Thanks
Andrew

 

[gavinda]

theres your answer. diy chem flush with restorer may work.