I know that this problem has been done before and I have scoured all the posts but neither I or my plumber can find the solution.
I recently bought my first house and had the bathroom refitted. In doing this I had a new bathroom suite installed including a basin mixer and a 3 way thermostatic bath/shower mixer with a concealed valve. As I understand both of these devices have non return valves fitted to them internally. The kitchen mixer tap is older but I have seen that both the hot and cold pipes have non return valves fitted. I also had a single feed shower pump fitted to the hot water service pipe attached to the cylinder.
My hot water system is indirect with a CWST in the loft, sitting lower beside this is the F+E tank. All the bathroom cold taps are supplied from the cold water mains. The CWST has only one inlet from the cold mains at the ball valve, which has recently been replaced to the part 2 version. There is one outlet that supplies the hot water cylinder.
The problem I am having since the installation of the bathroom is overflowing from the CWST, through the pipe into my back garden. The F+E tank is not overflowing at all. I have shut the mains water into the CWST and shut off the outlet valve. After an hour I found that the tank had almost filled up with warm water which was coming out the expansion pipe that hung over the tank. This overflowing was occurring before I fitted the shower pump.
Other diagnostics I have carried out included; isolating the hot water services by shutting off the valve on the shower pump. If I am not mistaken would this not rule out any faulty mixer taps inside the house. The overflowing still continued after this action. Only after shutting the mains cold water in the street did the overflowing actually stop.
I do have unbalanced pressure at my shower mixer and I was going to fit a pressure eqalising valve to the supply pipes, but I can't see how the cold feed could push past the non return valve and backfeed into the cylinder. Especially when I have isolated the hot services valve on the shower pump hose.
All I know is that some how the cold water pressure is pushing the hot services causing this overflowing.
Thank you for reading this long post.
I recently bought my first house and had the bathroom refitted. In doing this I had a new bathroom suite installed including a basin mixer and a 3 way thermostatic bath/shower mixer with a concealed valve. As I understand both of these devices have non return valves fitted to them internally. The kitchen mixer tap is older but I have seen that both the hot and cold pipes have non return valves fitted. I also had a single feed shower pump fitted to the hot water service pipe attached to the cylinder.
My hot water system is indirect with a CWST in the loft, sitting lower beside this is the F+E tank. All the bathroom cold taps are supplied from the cold water mains. The CWST has only one inlet from the cold mains at the ball valve, which has recently been replaced to the part 2 version. There is one outlet that supplies the hot water cylinder.
The problem I am having since the installation of the bathroom is overflowing from the CWST, through the pipe into my back garden. The F+E tank is not overflowing at all. I have shut the mains water into the CWST and shut off the outlet valve. After an hour I found that the tank had almost filled up with warm water which was coming out the expansion pipe that hung over the tank. This overflowing was occurring before I fitted the shower pump.
Other diagnostics I have carried out included; isolating the hot water services by shutting off the valve on the shower pump. If I am not mistaken would this not rule out any faulty mixer taps inside the house. The overflowing still continued after this action. Only after shutting the mains cold water in the street did the overflowing actually stop.
I do have unbalanced pressure at my shower mixer and I was going to fit a pressure eqalising valve to the supply pipes, but I can't see how the cold feed could push past the non return valve and backfeed into the cylinder. Especially when I have isolated the hot services valve on the shower pump hose.
All I know is that some how the cold water pressure is pushing the hot services causing this overflowing.
Thank you for reading this long post.