Is it a chance to substitute the boiler

Even if the furnace is generating hot water effectively, how this heated is allocated around the property can make a big distinction to how heated the property seems and the performance of the whole program.

Over time, air can get into the program and perform its way into the heaters themselves.  Generally, this will happen particularly in the biggest boiler in the property.  In this scenario the top of the rad will experience chilly (as it contains air, not hot water) through-which the hot water is operating, will experience hot. To fix this issue, basically start the air launch device (‘bleeding’ valve) at one of the finishes of the top of the rad with a little screw driver (or sometimes a unique blood loss key is offered with the radiator) and allow the water stress to force-out the air.  Once water begins to circulation out, near the device and examine that the top of the rad is now hot.

Boiler Replacement Crawley  installation will have ‘balanced’ the heaters by modifying the lock shield device on each of the heaters (the one on the rad that is not offered with a knob) so as to allow only a little water-flow through heaters near the furnace but a much bigger circulation through heaters that are further away.  This gives an even rad heat range throughout the property.  However, if you have had additional heaters fixed, or if the lockshield valves have been incorrectly modified, then the rad program will be out of stability and some heaters will be considerably chilly than others.  Rebalancing the program is a relatively easy job if performed systematically see, for example, http://www.local-crawley-plumber.co.uk/