This boiler is making a squeal at about 700 Hz on CH only most of the time but reduces if the CH flow is reduced by turning an isolating valve off. Its coming from the hydraulic block it seems from the right hand side.
I try not to go to any S-Ds at all but have never heard of this happening on one of these.
For those who dont know the Thelia is a tidied up SD620 with a white case but the aweful plastic inside.
Has anyone else encountered this before?
Tony
I try not to go to any S-Ds at all but have never heard of this happening on one of these.
For those who dont know the Thelia is a tidied up SD620 with a white case but the aweful plastic inside.
Has anyone else encountered this before?
Tony