What pump should I have installed for my hot (and cold?) water taps

[pedr0]

My unvented system was installed during a whole house renovation 5 or 6 years ago. There are two issues I'd like to address:
1) Hot water circulation on demand
2) Improve shower pressure

The hot water system has a circulation 'ring' whereby the hot water can get pumped out of the cylinder, through the pipes close to all the taps in the house, and then back into the cylinder even when no taps are drawing water. However, the installer put a pump controlled with a manual switch near the water tank (see picture of the pump below). Effectively I can choose to have the circulation pump running all the time or not at all. The pipes are not insulated . So of course, all the heat in the cylinder is lost if I run that pump for any length of time. If I don't run the pump - it can take over 2 minutes of running water in the kitchen before the hot water starts to come out.

Q1) What pump would you recommend instead of the current circulation pump? I suppose this would automatically turn on and off by sensing when water is being drawn from the taps.
Edit: Or is there a controller that I could add to the system that would turn the existing pump on/off when a tap is opened?

Q2) If the three showers are on at the same time, the pressure drop in each shower is very noticable/annoying. I must admit that I haven't tested yet if the pressure is maintained when the current circulation pump is on. But the circulation pump is only for the hot water anyway. To ensure consistent pressure, regardless of whether one person or three people are showering, what pump would be suitable? And would that pump both hot and cold?

Perhaps both questions are solved by one pump?

 

[oldbuffer]

1. Just put a timer on the electrical circuit to that pump, or fit a PIR light activated switch to turn it on when someone moves around the sensor.
2. It is really a circulator rather than a pure pump, and will have little or no impact on water pressure.
3. With simultaneous showers:
3a. It is more likely to be a flow rate issue than a pressure drop.
3b. Are the pressure and flow rate of your incoming mains supply up to running three showers simultaneously. If you have the specifications / installation instructions for the showers, tot up the flow rates. If the total is less than your incoming flow rate you aren't going to achieve simultaneous showers at your desired rate without improving the incoming.
3c. Worth checking the mains supply flow rates and pressures (static and dynamic).
3d. If the incoming pressures / flow rates are OK, you are looking at restrictive pipework / fittings as a source of poorer than required performance.

 

[Madrab]

If you wish to use a secondary circulator then you must highly insulate all the HW pipework, it would be madness not to. The circulator you have is fine, you just need to add the correct controls - Timers/PIR switches/relays/etc

You can't pump the outlet on an unvented system, the pump you have has nothing to do with the water pressure/flow

The mains dynamic pressure and flow should have been tested and checked that it would be suitable to deliver a suitable dynamic flow and pressure for your requirements, sounds like it wasn't if the system has always been like this. As suggested you will need to test the mains. That and the supply pipework and pipework to the outlets needs checked - to maximise flow you really want 22mm from the cylinder all the way out to the branches for the bathrooms.

I think you need someone in that is well versed (and qualified) in advanced HW systems to review your system

 

[pedr0]

Urgh - sounds like it was a bit of a botch job. Definitely no insulation on any of the pipes. No timers, PIR switches or anything like that.

 

[oldbuffer]

My post #2 should read ....if the total is more than ....