Bad mains pressure and ideas?

[Mike2007]

Can a auto-pump be used to create the mains pressure for an unvented cylinder, as mains pressure is only 2.5 bar static. I have read Grundfos do a mains supply pump and also thought about a shower pump being utilised for the purpose.
This property is in the remote countryside so creating good pressure might be totally unfeasible for a utility company to do?

 

[ChrisR]

YES.
Grundfos and others do pumps for the purpose.
So you can install a "break tank" and pump that. Some unvented cylinders can be used with pressures well above the common 3.5 bar, so you could use eg a 5 bar pump if you wish.
Or of course you could just pump the output from a vented system; there aren't many advantages in using a UV cylinder, if you're pumping. Or you could use a thermal store. Plenty of ways of cooking a cat.

If you're phobic about pumps you could put in an accumulator, which would cost more, be quite large and only provide a limited supply, at pressure below that of the static mains.

 

[Mike2007]

Whats the name of the Grundfos pump?

 

[ChrisR]

Depends on the details of the application.
Looked at their website???

 

[simond]

2.5 bar static is more than enough for a shower/unvented if you fit an accumulator, which will locally overcome flow rate issues and thus a potentially lousy working pressure if you are at the end of a long run.

When we fit accumulators on 3.5bar systems we often get asked whether we can turn the dynamic pressure down... it can be painful with high flow rate showers, and some people are worried about the bathfill performance. Turn round and it's full.

An accumulator doesn't usually work out much more expensive than a break tank assuming a good quality pump has been specified.

You don't need to go into the tank room when there's a power cut, or put up with the noise or the typically short operational life.

Finally an atmospherically sealed system is a lot more wholesome than a large open tank of water.