M
M4Matt
An age-old problem, but the cause is uncertain. I have a 2-year old David Wilson house (just out of warranty) with an unvented hot water system and seperate thermostats for the ground and first floor. Whenever water is pumped to replenish the hot water cylinder or to heat upstairs radiators I hear a grinding noise behind a downstairs wall near to the boiler (but evidently not from the boiler itself). The downstairs heating can run without this problem.
The noise lasts about half a second and occurs regularly every 5 seconds or so. The frequency does not seem to be effected by the speed of the pump or, if it is, the difference is minimal.
From what I have read elsewhere, I believe the noise is most likely to be air in the pipes or pipes rubbing against the wooden frame or support brackets. I would describe the sound as more like two surfaces rubbing against each other, but I have no plumbing experience to base this on. It also seems unlikely to me that air would be trapped downstairs in a pipe running from the bottom to the top of the house!
I bled all the radiators three weeks ago (first time in two years). Most had no air in, although one upstairs rad had a significant amount. When I bleed the radiators now there appears to be no further air. Also the pressure in the system seems to remain constant at 1 bar.
Any views on this and/or advice would be gratefully received. If air is the cause, would draining and refilling the system definitely solve it? If it is pipes rubbing against something, is there any option apart from pulling the house down???
The noise lasts about half a second and occurs regularly every 5 seconds or so. The frequency does not seem to be effected by the speed of the pump or, if it is, the difference is minimal.
From what I have read elsewhere, I believe the noise is most likely to be air in the pipes or pipes rubbing against the wooden frame or support brackets. I would describe the sound as more like two surfaces rubbing against each other, but I have no plumbing experience to base this on. It also seems unlikely to me that air would be trapped downstairs in a pipe running from the bottom to the top of the house!
I bled all the radiators three weeks ago (first time in two years). Most had no air in, although one upstairs rad had a significant amount. When I bleed the radiators now there appears to be no further air. Also the pressure in the system seems to remain constant at 1 bar.
Any views on this and/or advice would be gratefully received. If air is the cause, would draining and refilling the system definitely solve it? If it is pipes rubbing against something, is there any option apart from pulling the house down???
