Troubleshooting Negative Head Shower Pumps
Shower pumps are generally reliable pieces of equipment, and problems rarely occur. When they do, it's important to be able to diagnose them correctly in order to determine whether a new pump is needed or if the fault lies elsewhere.
Whether you're using Stuart Turner shower pumps or another brand, the basics of troubleshooting are the same. Problems are generally due to either the pipework connections, the electrical supply or the pump itself. We'll take a look at some of the most common issues and how to fix them.
Types of Pump
There are two main types of domestic shower pumps, and it's important to understand the difference, as using the wrong type can lead to problems. A negative head pump is used where the shower head is level with or above the cold water storage tank - in other words, gravity alone can't provide a sufficient flow for the shower. If the shower head is below the tank but water pressure is still low, then you need a positive head pump.
There are also universal pumps available that will work with either a positive or negative head type of system. If you have a combi boiler and no cold water header tank, then you need a pump that will boost mains pressure throughout the entire water system of the house, not just a shower pump.
Problems with Negative Head Pumps
Negative head shower pumps can sometimes suffer from the flow rate being too great at the shower head. You can solve this simply by fitting a larger head to cut the pressure and allow an even flow of water. Alternatively, you can try closing down the isolator valves for both hot and cold water on the output side of the pump slightly. Don't close them by more than a third, and leave the valves on the input side fully open. You may have to use a bit of trial and error to find the right flow.
Often problems aren't with the pump itself but with the electrical supply feeding it. If your pump isn't operating at all, the first thing to do is check that the power supply is on. There will usually be a fused spur feeding the pump: if the power is on, locate the spur and check that the fuse hasn't blown. If there's a circuit breaker, similarly check that it hasn't tripped. Should your pump continue to blow fuses after they've been replaced, then that indicates a fault with the pump itself - possibly a seized motor.
Some pumps have run-dry protection, which causes them to cut out to prevent damage if the water supply is interrupted. This can look similar to an electrical problem at first glance. If the run-dry cut-out has operated, you can reset it by turning the power off for ten seconds and then turning it on again. Open the shower tap to get any air out of the system.
Noise from shower pumps is a common complaint. Check that the pump has been properly installed. Most are supplied with anti-vibration feet, so check that these have been properly fitted. Noise can be transmitted through pipework, so make sure all pipes to and from the pump are properly supported. Also check that any flexible hoses have minimal bends. If the pump makes a humming noise, this may indicate that it's stuck. This could be due to an electrical problem or, in hard water areas, the pump being blocked by limescale.
Leaking from around the pump may be caused by a joint that hasn't been sufficiently tightened or by badly fitted or worn washers. Pumps are usually fitted with isolation valves at either side, so it's an easy matter to disconnect and re-seat the joints without turning off the whole water supply. If the leak is coming from the pump itself, then it may need to be serviced or replaced.
Trying to fix a noisy or broken shower pump? Read our complete guide here.