Shower Pump for Rain shower Head.

Currently using a ShowerForce Easiboost 1.5bar shower pump feeding a Mira 8 mixer valve to a Rain shower head of 20 cm dia via 15mm pipe and the pump in/out pipework of 15mm. This has been use for some 15 years.

The pump is increasingly getting noisy. The pump and ShowerForce show no details of its flow rates, only the pressure of 1.5 bar.

Asking for advice of delivery rate I should look for as a replacement.

Take off shower head and turn on an individual outlet or put it on full cold and run into a bucket. Time it for a minute then measure how much water you have, that'll give an approx flow rate to work with.

Whether there's a connection as to why the pump becoming noisy.

Periodically I have to bleed the system, as occasionally the shower runs cold no matter of the heat settings on the mixer. The hot water feed is hot a the point of entry to the mixer but shower still runs cold. But if I turn the pump off electrically and run the shower for 2 mins, and switch the pump back on.

All is OK again.

The pump is installed as per instruction where its on the floor and both feed pipes are swept down to the pump with no elbows etc and same to mixer apart from having elbows to go through the wall to the mixer.

What could cause an Air Lock and what could be done to help prevent it.

How is the pump fed from the hot water cylinder, is there a dedicated supply to the pump or is it fed from the shared hot water supply pipework?

The hot side of the pump (seals/bearings/impeller)could be getting worn if air/bubbles are being drawn in from the cylinder.

Its Fed to the mixer from the original gate valve, which is horizontal above the tank. As for being spurred off any HW supply will have to check and come back.

OK,

The outlet at the top of the tank sweeps to a Tee piece. One end to the shower and the other to the HW tap system.
It is a known thing in the household, not to run any HW taps in the house otherwise One will have a cold shower.

Yeah, that'll be why. Most manufacturers do allow for a feed to the pump from a tee from the main distribution outlet from the cylinder but it should always be angled upwards and at least 300mm from the vent.

It's certainly not ideal though as air bubbles can still be drawn into the pump from the main feed pipe and the pipe can actually be drawn out a little sometimes introducing an air lock, if there's high demand elsewhere on the HW circuit. That'll be why you have to bleed the pump occasionally.

Any dry running of the pump can damage the impellers, seals and then bearings, especially if it keeps occurring, that ends up in a noisy pump and given the spin rate and load they can be under, they can deteriorate quite rapidly once it starts.

As best practice I always try to plan in a 22mm feed to give the pump as much water as it can take, same on the outlet supply to maximise flow, they should be dedicated feeds for hot and cold from the cistern and from the cylinder(via a flanged outlet). Ideally keep the pump at the bottom of the cylinder and maximise the non pumped head of water to the shower head/outlets, if needed, buy raising the cold cistern as high as possible above them. Finally try and avoid the pumped supply rising up back above the outlets once pumped.

Thanks,

Yes the outlet from the pump did travel over above the shower mixer, now re-routed.
Yes the cylinder outlet and shower/pump supply has to be changed, currently from the tee to the main circuit is 22mm and to shower/pump 15mm. Next job.
The cold water cistern in the attic is already raised to its max. allowing maintenance access.

Thanks