Rads not so hot

[Grahammanu]

My rads are not so hot as they used to be. Have been told that they may need sentinal x 400. I have a combi boiler so how is this applied to the system and how long does it have to stay in system for and what do i have to do after.
Please help as i need all the help i can get.

 

[gasmarc]

have you tried bleeding the rads first

 

[Grahammanu]

Yes done that .

 

[gasmarc]

who told you yon needed sentinal ?

 

[Grahammanu]

Looked on web site.

 

[Centralheatking]

There are loads of reasons why the heat is not as good as it was/should be.

Heating system How old ? how big ? boiler type ? pipe size ?

All rads not hot or just some - all rads check stat and boiler setting. Post
some info before wacking in chemicals etc.

centralheatking

 

[Grahammanu]

all the rads are not very hot. System same as last year when we had no probs at all and boiler setting is turned all the way up .

 

[Centralheatking]

Have you checked your room stat - box with circular dial

centralheatking

 

[Grahammanu]

Have never had room stat.

 

[fuzzy]

never had a room stat? how old is the system? what turns boiler on and off, just a timer