Posted by Adam on October 17, 2001 at 11:00:09:
Hi I’m making a call from the UK with a boiler installed in France.
I recently replaced an ageing woodstove with back boiler with an oil boiler with only the one flow and return... There was only one flow and return on the back of the woodstove so gravity feed the cylinder and a pump feed the radiators. I have left a swept reduced Tee in the system, which helped with the flow; all the pipe work is in 28mm to the cylinder and 22mm on the radiators. Unfortunately, the new position of oil boiler is above the lowest part of the pipe work (and before you say there is no way to move the pipe work up)….. The pump was placed to pull the return of the radiators the other side of the tee (e.g. after where the return comes from the cylinder). I had to move the pump to the other side of the tee next to the boiler return, because with the boiler on full blast no hot water was being circulated, only the water in the radiators system was flowing and because the boiler was above the lowest pipe work gravity didn’t work so the cylinder didn’t get hot either, (I guess the thermostat on the boiler stops the water over heating force a vent). Anyway, moving the pump seems to have fixed it and seem to let even heat distribution between the cylinder and the radiators. As you can image I have no control. I haven’t yet put a pressure relief valve on the circuit or the boiler because I not sure where or if it will interfere with gravity venting?
Can I put a 3 port mid position motorised valve in where the tee is, with switching from a thermostat on the cylinder and room stat, or do I have to have two 2 PORT ZONE MOTORISED Values on to control flow to the cylinder and another to control the radiators? If this is the case Why and Where? Is it because of unrestricted flow to the vent?
If I need two motorised valves what is the wiring? Am I thinking about in the correct way if I say I need the cylinder stat to control the valve on the hot water side and the room stat on the valve controlling the radiators? How do I wire this up to the boiler and a timer?
Well thanks for any suggestion! hope I have made myself clear enough…
Adam.