Which pump from the hot water cylinder to the hot taps?

[Chris333]

My cold water pressure is OK (all cold water taps are off the mains) but the hot water from the hot water cylinder tank is weak pressure all around the bungalow.

I just want to increase the pressure of the hot water from the water cylinder (which is about 18" off the floor in the airing cupboard).

Which pump do I need to get?

 

[ALCPlumbing]

As you will be using the pump for multiple outlets my advice would be to get a single pump (as it's only for the hot) that has 22mm connections so it can cope with the demand. I tend to recommend and install Stuart Turner Monsoon pumps.
You can get cheaper pumps but these are one of, if not the best pumps on the market. You can register the pump online and extend the warranty to two years for free and also spares are easily obtainable.
If this is going to be a DIY project make sure you fit a Surrey flange onto the outlet of the hot water cylinder. This makes sure that any air will be vented without being sucked into the pump.
You should also test the pressure of your mains and choose a pump with a similar pressure as it's advisable to have equal pressures at the outlets. A non-return valve should also be fitted on the outlet of the pump to ensure the mains doesn't push it's way into the cylinder.
I hope this helps.

 

[muggles]

If you're intending to fit a single pump (hot only) to mixer valves, and those valves are fed by mains cold, you'll also need to put double check valves on all the cold supplies. If you have tank-fed cold to your mixer valves at the moment, you'll need a twin pump for hot and cold. Have a look at the Grundfos Amazon range of pumps

 

[Classic40]

Grundfos UPA 15/90 http://www.wickes.co.uk/UPA-15-90N-St-Steel-Pressure-Booster/p/228263 ?

 

[Chris333]

On my hot water cylinder tank it says "tested to 1.45 bar". Does this mean that I can only put a 1.45 bar water pump on it or can I put on a higher rating?

 

[JohnD]

1.45 bar is the pressure you would get from a water tank on a tower about 45 foot tall, so more than enough.

But since you will be sucking from the cylinder, not blowing into it, it is irrelevant.

 

[Chris333]

Grundfos UPA 15/90 http://www.wickes.co.uk/UPA-15-90N-St-Steel-Pressure-Booster/p/228263 ?

That looks good, but it says "typically adds between 0.5 bar and 0.75 bar pressure". Is a more powerfull one available?

 

[Classic40]

Grundfos UPA 15/90 http://www.wickes.co.uk/UPA-15-90N-St-Steel-Pressure-Booster/p/228263 ?

That looks good, but it says "typically adds between 0.5 bar and 0.75 bar pressure". Is a more powerfull one available?

Not that I am aware of without getting a shower pump. Saw this; http://www.showerpowerbooster.co.uk/ but I don't think it will be anywhere near as good as the UPA 15/90.

I have the same issue you have, good cold pressure but poor hot due to the CW tank only being 2.5 meters above the cylinder; 0.25 bar.

If it adds 0.5 bar to the current 0.25 bar I have it's like 2 times more powerful then it was before.

The only other thing you could do is raise the CW tank, but 1 meter is 0.1 bar so will need to go a lot higher to make it worth while.

 

[AngelesPlumbing]

Time to change unvented system

 

[longdogs]

When I fit whole house pumps, I always fit a bypass which is handy if the pump is removed for any reason or not working.

 

[Chris333]

Would this one work for what I want to do? (pump from the hot water cylinder to the whole house?)

http://www.salamander-pumps.com/complete-pump-range/rgp-pumps/rgp80-single-booster-pump.html

 

[longdogs]

Yes that's fine. Does it come with flexi connectors?

 

[Chris333]

Yes that's fine. Does it come with flexi connectors?

Yes.

 

[Chris333]

I phoned Salamander and asked them which pump I should get.

They said the Salamander ESP80 CPV Single Pump 2.4 Bar.

I can't work out why that one instead of the RGP80 2.4 bar. They said because the cold would be off the mains. I can't see why it would make any difference on a single pump from the hot tank.

 

[Chris333]

Just to give people an update...

Before: I had terrible hot water pressure around the bungalow from my gravity fed hot water tank. There was barely a dribble of hot water from the bath shower mixer taps. The cold was fine as it was direct from the mains.

After fitting a Salamander ESP80 CPV Single Pump 2.4 Bar to the hot water cylinder via a warix flange:

The pressure is now fab for a great shower from mixer taps on the bath, and all the taps now have good hot water pressure.

It took me months to work out what the best solution might be.

The pump works on either negative or positive head systems and has a cut-out feature to protect the pump.