Can a combi hose down pump be serviced if so how? i have a valliant combi boiler ecomax800 it give us hot water...

i have a valliant combi boiler ecomax800 it give us hot water but no heat it will keep maxim pump overrun and iwas wondering if it can be serviced by diy or does it need replacing
Answers:    I answered your interview yesterday, I am answering people who save harping on about individual able to work on gas lacking being corgi registered, contained by your own home, you can do what you like, probability are you do not have the knowhow or equipment to test properly, and in consequence should not do it, if your insurance company find that you messed with your gas, they will not earnings for any damage you may do, if you damage vivacity or property you will likely travel to prison, little knowledge is a perilous thing, professionals sometimes carry it wrong, so it follows that somebody who is not a pro, is more likely to bring back it wrong, typically, someone who asks the same examine, and is given several answers by professionals and takes no discern, should definately not be trying diy gas or electrical work.
It is unlawful to service/repair boilers in the uk unless you are corgi registered. wish professional advice