I have a pump that appears to be running but not pumping water.
This type of condition could happen for a number of reasons. Check to ensure the pump is connected the right way round. Then ensure the pump has a flooded suction and that the water supply valves are turned on. For the first time of running the pump and supply pipework will need to be bled through removing any possible air locks.
My positive head twin pump will not start.
Check the simple things first, make sure the fuse is sized correctly and functional, check the power is turned on and the circuit breaker is set, then check the wiring, it is easy to screw down on the insulation rather than the copper tails when connecting the wires. To work, these pumps need a flow of at least 1.0 litre / minute. If when opening the outlet to be pumped, the flow is less than this it will not be sufficient to start the pump.
I have a positive head twin pump and it keeps running on.
If this pump has just been installed close both isolating valves on the outlet side of the pump and see if the pump stops. If it does, then this indicates there must be a tap or outlet being pumped that is open to atmosphere. Check the system and find where the pump is pumping the water to. If the pump does not stop when closing the valves, check to see if the reed switch on either end has become blocked with debris. Disconnect the pump and flush water through it to dislodge any debris and free the reed switch.
We have a negative head twin pump and the flow rate is too great. Is there any way to reduce the pressure or limit the flow?
The pressure the pump delivers the water at is directly proportional to the amount of water being used. Therefore if your problem is that the pressure is too great at the shower head, fitting a larger shower head would increase the water flow and the pressure will be lower, but remember you will be using the water faster so your stored hot water will not last as long. The simplest way of reducing the performance is to close the outlet isolating valves down no more than 30% on both hot and cold flows thus restricting the water flow. Never restrict the water flow on the pump supply side.
My shower is fed through a mixer tap with the cold water coming from the mains and the hot water from a gravity-fed tank. I need a pump to boost the hot side of the system. What options can you suggest?
The best way forward here is to use a negative head single pump, of a size to suit the shower you have. Where cold water is being supplied to the mixer valve and hot has to be delivered to the same unit, the pump has to be able to provide and maintain water pressure on the hot side so that when the valve is opened the pump senses the pressure drop and starts.
What’s the difference between Positive and Negative pumps?
Where a minimum gravity flow of water in excess of 1.0 litre / minute is present, then this is known as a Positive head condition. When an outlet (tap or shower head) is above or level with the cold water storage tank then this is known as a Negative head condition. Negative head pumps are specifically designed to function under Negative head conditions whereas our positive head pumps are for use where an open vented Positive head condition exists.
My negative head pump keeps turning on and off, how can I fix this?
Check for any leaks in the system. Check the tap washers and pipe joints etc.
My pump seems noisy, is there anything I can do to reduce the noise?
Ensure the anti-vibration feet are used. Ensure all pipe work to and from the pump is independently supported. Pump should be placed on a concrete slab to reduce vibration through the building structure.
My negative head pump has ‘run-dry protection’ which has cut in, how do I restart it?
To reset the dry run protection, switch off the electricity supply for 10 seconds and then switch it on again. This process will reset the control circuit, returning it to normal operation once again. Now open and close the taps, purging the system of air and allowing the pump to switch off normally.
My pump keeps “humming”, what is wrong?
This is a sign of the pump being jammed or stuck, stopping the free rotation when required. This could be as a result of infrequent use in a hard water area for instance, where the seals or other moving parts can become stuck, or alternatively this could be as a result of an electrical issue. You will probably need a qualified service engineer to sort this problem.
My pump is leaking, how can I solve the problem?
Turn off the isolating valves on both the suction and delivery side of the pump. Arrange for a pump engineer to inspect, or alternatively buy a new shower pump.