Circulating problem

[BoilerPro]

Sime Oil fired boiler, probably sealed system. Industrial unit, not home. Boiler reaching temperature but nothing to rads. Pressure low but filling loop making no difference. (Have seen this before and we call it an Irish solution to an Irish problem, i.e. it has all the equipment for a sealed system but is actually an open system). Circulating pump appears to be working in so far as it is spinning. Have traced system as much as is possible and can't find anything like a motorised valve, so it seems that either the pressure is too low as indicated by the pressure guage (but can't rely on it as stated above) or the circulating pump is making all the right moves but not actually working. Is this possible, or do they just stop? Also, whenever I've used a filling loop to refill system I have always felt a rush of water while tap is open, but feel nothing this time. Customer did bleed rads and said there was "a lot" of air in one of them but rads full now. What am I missing?

Kevin

 

[stevetheplumber]

if system is full and no valves closed its either pump or blocked but pump most likley

 

[BoilerPro]

Thanks Steve. So, the circulating pump might appear to be working but actually not?