u might have sludge in the rad which will take longer to heat up. If its cold near the middle/bottom of the rad it's sludge if its cooler at the top, its air. if after hosing out its still cooler, it will be balance or a new rad. use a different rad from elsewhere to see if it warms up quiker...
If your water was black and thick like oil you seriously need a good flushing but before paying for a flush try and drain your whole system first, this should take about 20mins. Open all of yor valves and drain at the lowest point. open the bleed valves after a while to allow it to drain...
forget all liquids that you can purchase, forget a plumber... I had both sink and bath blocked and after throwing sink unblocker down the drain with no effect I decided to use my kercher jet wash.. stick the nozzle into one of the little holes and put a towel over the plug hole for any...
forget all liquids that you can purchase, forget a plumber... I had both sink and bath blocked and after throwing sink unblocker down the drain with no effect I decided to use my kercher jet wash.. stick the nozzle into one of the little holes and put a towel over the plug hole for any...