Problem with Salamander pump feeding shower


I have oil-fired central heating system. Salamander ESP100 pump was installed (by a pro) about 2 years ago to feed a mains-fed shower. The pump is located on the same floor level as the shower. Over recent months its been taking longer and longer for the pump to kick in when shower is turned on. We have to repeatedly turn shower on off, and hold shower head at lowest possible height before pump kicks in.
Any idea what is wrong?
Also, the darn thing is extremely noise; I have placed it on top a price of carpet on top of chipboard flooring boards (the problem described above started long before I did this so). Any other suggestions to reduce the noise?
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Most shower pumps have filters which need cleaning out. Try this 1st.
ken
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Sounds to me like the flow switch(es) are shagged. Ours has reed switches which are ca 7pounds each from the manufacturer, or a couple of quid from Maplin. Don't know what other sorts of flow switch are out there.
If the pump hasn't always been noisy, then I would suggest that the noise is either (a) air in the pump, or (b) the bearings on the way out. (a) will lead to (b) as the bearings are usually water lubricated & trapped air will cause them to run dry & wear out.
Air can be drawn from the water as it boils - under reduced pressure (eg the suction side of the pump) water can boil at 60degrees C and dissolved oxygen is released in the impeller area. Make sure your cylinder thermostat is around 55degrees C or lower. try turning it down until it is too much, then nudging it back up a bit. The damage may already have been done, but you might slow its demise.
BTW I was thinking of buying a Salamander pump when the current incumbent expires. Maybe not now....
Jonathan
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