I'm going to provide a long and short version. The longer version provides some background because this latest problem is one of a series we have had, and they may be related.
For reference, our shower uses a Mira pump, and an Alph Exposed Thermostatic Shower Mixer Valve (http://www.plumbworld.co.uk/alph-exposed-thermostatic-1738-26402). I'd be very grateful to anyone who can suggest a cause and solution. Both the controller and pump are new.
Short version: our shower pump does not detect and start when the shower controller is turned to an 'on' position. It used to be fine, only a few weeks ago (newly installed). Then it started only detecting if the temperature control was turned to cold as well (and a little cold water dribbles out). Now the pump will only come on if you can get quite a flow of water going, usually through unscrewing the warm water inlet from the shower controller, or by taking the temperature controller off and setting to cold and "playing" for a while (switching between on and off, and altering temperature) until it comes on.
Longer version: We bought a new house and the previous owner left us a note saying "Sometimes the shower pump doesn't switch off. Turn the shower on and off again and it'll go off. Pump is only a year old". This was true, it happened occasionally that when you turned the shower controller to off the pump stayed on, but turning the shower on and off again would usually work, occasionally a second attempt was required. But this happened more and more frequently and sometimes a third and fourth and fifth attempt was required. A friend suggested the pump cut off valve was stuck. I phoned the pump manufacturer (Mira) to get a replacement under warranty but they informed me that their warranty was not transferred with the purchase of a house. Eventually a plumber came, suggested we buy a new pump, and fitted it. Everything was fine, except that, occasionally, the pump would cut out after a while (10 minutes or so) and the shower went cold. Plumber believed the thermal cut-off in the pump was kicking in and ordered a replacement pump under warranty. This came and was fitter. However, he pointed out that our temperature control on the shower wasn't working. He suggested that this was an old problem, could have been connected to the thermal cut-off problem with the previous pump, and had not previously been noticed because the 'stuck' temperature it was fine and we probably never noticed. I don't know whether this was true. Unfortunately with the new pump the temperature was far too hot. The plumber persuaded us that we needed either a new shower controller or a new internal cartridge. Given the price difference was small, we elected to buy a new controller. The plumber was not available to fit the shower controller, but he told be it was simple and I would be able to do it, which I did and everything was fine to start with. But after a few weeks sometimes the shower pump would not start when switched on. The immediate fix was to turn the temperature control to cold. A small amount of cold water would trickle out and the pump would start. This got more and more frequent and then, sometimes, the 'cold' trick would not work, and the only ways to get it working were to take the temperature knob off and alter the internal temperature piece, or to unscrew the hot water inlet to the mixer to get some hot water flowing. This has again got more frequent so that, now, it will invariably only start with intervention of a spanner.
For reference, our shower uses a Mira pump, and an Alph Exposed Thermostatic Shower Mixer Valve (http://www.plumbworld.co.uk/alph-exposed-thermostatic-1738-26402). I'd be very grateful to anyone who can suggest a cause and solution. Both the controller and pump are new.
Short version: our shower pump does not detect and start when the shower controller is turned to an 'on' position. It used to be fine, only a few weeks ago (newly installed). Then it started only detecting if the temperature control was turned to cold as well (and a little cold water dribbles out). Now the pump will only come on if you can get quite a flow of water going, usually through unscrewing the warm water inlet from the shower controller, or by taking the temperature controller off and setting to cold and "playing" for a while (switching between on and off, and altering temperature) until it comes on.
Longer version: We bought a new house and the previous owner left us a note saying "Sometimes the shower pump doesn't switch off. Turn the shower on and off again and it'll go off. Pump is only a year old". This was true, it happened occasionally that when you turned the shower controller to off the pump stayed on, but turning the shower on and off again would usually work, occasionally a second attempt was required. But this happened more and more frequently and sometimes a third and fourth and fifth attempt was required. A friend suggested the pump cut off valve was stuck. I phoned the pump manufacturer (Mira) to get a replacement under warranty but they informed me that their warranty was not transferred with the purchase of a house. Eventually a plumber came, suggested we buy a new pump, and fitted it. Everything was fine, except that, occasionally, the pump would cut out after a while (10 minutes or so) and the shower went cold. Plumber believed the thermal cut-off in the pump was kicking in and ordered a replacement pump under warranty. This came and was fitter. However, he pointed out that our temperature control on the shower wasn't working. He suggested that this was an old problem, could have been connected to the thermal cut-off problem with the previous pump, and had not previously been noticed because the 'stuck' temperature it was fine and we probably never noticed. I don't know whether this was true. Unfortunately with the new pump the temperature was far too hot. The plumber persuaded us that we needed either a new shower controller or a new internal cartridge. Given the price difference was small, we elected to buy a new controller. The plumber was not available to fit the shower controller, but he told be it was simple and I would be able to do it, which I did and everything was fine to start with. But after a few weeks sometimes the shower pump would not start when switched on. The immediate fix was to turn the temperature control to cold. A small amount of cold water would trickle out and the pump would start. This got more and more frequent and then, sometimes, the 'cold' trick would not work, and the only ways to get it working were to take the temperature knob off and alter the internal temperature piece, or to unscrew the hot water inlet to the mixer to get some hot water flowing. This has again got more frequent so that, now, it will invariably only start with intervention of a spanner.
