I've just fitted a new zone valve as the old one was not closing so I always had CH if just wanted HW. The problem is now that if I put HW on only I get HW only but there are noises from the pipes / pump that dissappear as soon as the flow starts on CH. The noises are initial banging if starting on HW from cold and a general low level rumbling. I notice that the feed to coil is hot and return from coil is cold so you would expext the boiler (baxi solo) to be fired up but it's mostly not when HW only is on. The water is taking a very long time (3-4 hrs to heat up). The feed / return to the coil is 15mm. The other thing I notice is that the 22mm flow pipe leaving the boiler almost immediately joins the 22mm vent to f&e ciistern then the pump. I read that the feed from the f&e cistern should be within 150mm of the vent to avoid problems and it's not it joins the return from the HW coil as it exits the cylinder, which in distance is about 10 metres. I read that if in this position it would cause a negative pressure and a sucking effect as it is behind the pump. I'm not sure if I need a flush or should move the cistern feed to next to the vent? Any ideas. I ran x400 for a week and now have x100 and x200 in the system and have bled it. The coil is not scaled on the outside as I looked through the immersion hole with a torch, very little scale. I did have a short spell of pumping over, but before the last draining. Not sure if it's because the thermostat on the boiler is on 3 instead of 4 or the chemicals helped but it's stopped.
- posted
18 years ago