Pump to boost hot water to whole house & new shower?

[Chris333]

I live in a bungalow that has terrible hot water pressure.

We don't have a proper shower only a rubber hose connected over taps.

The water flow from it at shower height is 2 to 2.25 litres per minute.

All of the cold is off the mains, there is a hot water cylinder tank and gas boiler.

I really need a thermostaic shower with a good water pressure.

Do I need to buy a pump to just pump the hot water around the house and a mixer shower?

Would it be legal if the cold is coming from the mains?

 

[lizard1975]

Yes it would be illegal, and more to the point highly dangerous. If for any reason the mains cold was to be turned off, you would still have hot water being pump into the shower that was no longer mixing with cold water.

Depending on your place, the easiest and cheapest method would be to fit and electric shower off the mains. However if you want a mixer shower off the hot water tank, you would also need to fit a cold water tank feeding the shower as well, with both the hot and cold water running through a pump to the shower.

 

[Chris333]

Yes it would be illegal, and more to the point highly dangerous. If for any reason the mains cold was to be turned off, you would still have hot water being pump into the shower that was no longer mixing with cold water.

Depending on your place, the easiest and cheapest method would be to fit and electric shower off the mains. However if you want a mixer shower off the hot water tank, you would also need to fit a cold water tank feeding the shower as well, with both the hot and cold water running through a pump to the shower.

I am trying to avoid an elec shower.

There is a cold water tank in the roof which I think feeds the hot. Would I also take a feed off that for the cold?

 

[lizard1975]

Afraid not, that tank is their to feed the hot water cylinder so as you get an adequate amount of hot water. When that tank is empty (which would happen quite fast with a pump) the cold water would stop flowing to the shower, but the hot could continue depending on the safety features of the pump

 

[Chris333]

Afraid not, that tank is their to feed the hot water cylinder so as you get an adequate amount of hot water. When that tank is empty (which would happen quite fast with a pump) the cold water would stop flowing to the shower, but the hot would continue.

but wouldn't a thermostatic shower protect against being burnt?

 

[lizard1975]

but wouldn't a thermostatic shower protect against being burnt?

Yes, but their is a minimum size your cold feed tank would need to be, it use to be 114 litres (25 Gallons) or if other outlets are likely to be used at the same time 228 litres (50 gallons). However its been so long since i've done one of these that im not sure if the regulations have changed

 

[Chris333]

but wouldn't a thermostatic shower protect against being burnt?

Yes, but their is a minimum size your cold feed tank would need to be, it use to be 114 litres (25 Gallons) or if other outlets are likely to be used at the same time 228 litres (50 gallons). However its been so long since i've done one of these that im not sure if the regulations have changed

If I had:

A) Thermostatic mixer shower,
B) A pump off the HW tank,
C) Cold off the mains

I'm prob being thick but I can't work out what would be wrong with that. It would be the same as what is there already on the taps, only that there would be a pump on the HW.

 

[lizard1975]

Have you considered swapping your open vented hot water cylinder to an unvented one? a dual pump is not that cheap to buy and then you also have the cost of installation (mains/water)

Where as unvented cylinders have fallen a lot in cost, and would give you mains pressure hot water at all your tap outlets so removing the need for any pump. Also they are the most efficient way of heating hot water.

 

[lizard1975]

I'm prob being thick but I can't work out what would be wrong with that. It would be the same as what is there already on the taps, only that there would be a pump on the HW.

Its a valid question, and when i answered it i was still thinking of the days of non thermostatic mixers . Darn but this site makes you think

Single pumps are designed to handle cold water not hot, also the pressure to the mixer would not be balanced pressure which would effect its operation. Lastly their is a possibility in certain mains faults of the hot water being sucked into the mains cold water supply

 

[Chris333]

Have you considered swapping your open vented hot water cylinder to an unvented one? a dual pump is not that cheap to buy and then you also have the cost of installation (mains/water)

Where as unvented cylinders have fallen a lot in cost, and would give you mains pressure hot water at all your tap outlets so removing the need for any pump. Also they are the most efficient way of heating hot water.

Many thanks, I didn't know that they existed.

The hot water tank I have is a Herculag 50, 900mm x 450mm, 117 litres. (says on label tested to 1.45 bar).

What sort of money would it cost to replace that with an unvented?

 

[phatboy]

Have you considered swapping your open vented hot water cylinder to an unvented one? a dual pump is not that cheap to buy and then you also have the cost of installation (mains/water)

Where as unvented cylinders have fallen a lot in cost, and would give you mains pressure hot water at all your tap outlets so removing the need for any pump. Also they are the most efficient way of heating hot water.

Many thanks, I didn't know that they existed.

The hot water tank I have is a Herculag 50, 900mm x 450mm, 117 litres. (says on label tested to 1.45 bar).

What sort of money would it cost to replace that with an unvented?

I'd reckon about £1000 if its a straight swap. But I would think you wanted more than 117L, thats tiny!

 

[lizard1975]

You could buy a cylinder of around that size for about £450 plus VAT, which would come with a 25 year guarantee if you shop around. Cheaper ones will have something like a 5 year guarantee. The more expensive ones will give an increased flow rate (unlikely to be an issue) i.e. 6 bar pressure instead of 3.5 bar max pressure, but more importantly an increase heat up time ie will heat the cylinder in under 20 min (providing your boiler is large enough) instead of 30 minutes or so. However as you live in a bungalow then i doubt that your boiler would be large enough to allow for this increased heat up time. Plus fitting of course

 

[Chris333]

Ummm.... I am still not sure what to do due to the cost and that I have a lot of other expensive work to do on the house.

Thanks!