by ericmark »
Tue Jan 22, 2008 8:45 pm
The Combi boiler saves room, can be more efficient this depends on lagging on cylinder eliminates external control and shower (one) can run direct with medium pressure. It takes longer to fill a bath, and can’t supply multi-showers at same time you can’t fit a power shower. Plus in your case you need to alter the plumbing.
Both Combi and conventional boilers now have a range so instead of switching on and off there output matches demand which works better with TRV’s and most are condensing so a lot more efficient. Many people assume this is only the case with Combi boilers but this is not the case. Having external pumps and valves can cause problems were incorrectly wired or set up especially with the anti-cycle functions.
Many Combi boilers have it all built in including anti-cycle the latter on a Combi only works on the central heating and is basically a timer which stops the central heating re-starting once the boiler has switched of after going below the minimum output until a set time has elapsed. This means not room thermostats are required the TRV’s do all the work. Although this can be fitted to non Combi boilers it is not common and a thermostat is normally required to switch the central heating off once all rooms are warm. So small houses better with Combi but larger houses better with non Combi not necessary open vented the closed system can’t leak as much water if leak happens and central heating water can be hotter although that would also require enclosed radiators. I hope that helps?
