Downstairs not getting hot after changing some pipework layo

[tonylds]

I've rerouted some pipes and now my upstairs radiators are fine but there is no heat at all from my down radiators. If i turn off a rad upstairs the heat travels further down the pipe so I think I've got a flow problem. To prove a point I've put the system back (nearly) as it was to see if the problem would clear but another (unconnected ?) problme has now occurred - my pump has packed up (it was squaling) I've opened it and found that the drive has sheared off. I'm going to get another pump now but does anyone know if there should be problems such as no downstairs heat just because I've rerouted some pipes. I'm hoping that my pump was on its last legs and so wasn't creating enough flow to pass the water along a 1m length of pipe before it went down from the loft. In my new layout I've added about 5 more 90 degree bends. Is this likely to cause reduced flow problems. I'm hoping that my new pump will cure all but any advice would be appreicated. I've noticed a simlar post from caroline and the suggestion is that there is sludge clogging the system somewhere. If this is the case could a blockage in my downstairs system have causes too much load on my pump to shear its shaft. THis seems unlikely to ne because flow was paaing around the upstairs rads ok.

 

[oilman]

Taking the last point first, blocked pipes reduce the load on unsealed impeller type pumps. The load is highest when the pump is shifting water.

If your layout changes have given you an un-vented high point, then you will have trouble; it's an airlock!!. First check for high points and then put some vents in. It's very easy to get air in the system, and really hard to get it out. I have this trouble all the time. And it will take days sometimes to get the air out.

If your pump sheared off, I suspect you didn't have enough corrosion inhibitor in the system. It needs topping up every three years at least.