hi , i have just added another radiator to my system, making 3 in total all downstairs, by continuing on from where it enters the last radiator and joining back the return the same way , all pipework is in 15mm, the bit ive added on ive done in push-fit about 4m worth there and back, it is a solid fuel system ,with a pump on the flow , which only has 2 settings off and on, rads and pump have been bled and the water in the rads warms up straight away ,but does not stays warm not hot ,i have not flushed the system because i used push-fit , do you think i need to flush the system or do you think i need a bigger pump or both. the 2 rads worked fine before , fire has been in for days so the water would be red hot , got me scratching my head this any help welcome.