radiator's barely warm

[runci21]

ive got a multifuel stove which has a water output of 13 kw ive got 9 radiators in the circuit and a hot water tank .
after fire is lit and up to temperature the pipe that goes to the hot water tank gets hot and when the return to fire gets hot the radiator pump kicks in and within an hour all pipes cold and is rear of stove .
ive checked that the pump is on its slowest setting and all radiator valves are set right
any ideas anyone ???/

 

[kevplumb]

size of rad's

13 kw ain't a lot

 

[runci21]

2 x 500 singles
5 x 1200 singles
1 x 800 double
1 x 1200 double

 

[tryitandsee]

shouldn't the fire be a secondary heat source and 'help out' a primary heat source i.e. main boiler, when the fire is alight.

It seems a lot of rads to satisfy with back boiler only.