Vented Combination Tank fitting Shower Pump. help please!!!

[Nat21]

Hi

I wish to fit a shower pump to increase the flow for the hot water to my shower. Used electric showers in the past but what to improve things.

It is a one bedroom flat with the hot water tank is on the same leave as the shower. From what I understand I need a negative shower pump? Correct?

I have also heard that I might need a flunge? To correct the pressure? Is this correct? Or is the negative pump all I need? The tank is a Elson Opal economy 7 heating system, no gas. Don't really fancy drilling into the tank, If it isn't required!

Please help! Really don't want to go back to an electric shower, hoping the pumped will give a better performance.

Any help is great!!!

Nat

 

[Hugh Jaleak]

Pumped showers need hot and cold supplies, with the setup you have it wont work. The cold tank will be emptied within seconds... Unfortunately I think an electric shower is your only option.

 

[Nat21]

Hi thanks for the quick reply!

The cold is through the mains which is at a very good pressure. Would this change what you say? Or do you mean the cold which is at the top of the Water Heater?

 

[seco services]

cold water storage to the tank is to small.

 

[TicklyT]

Normal practise is to balance the hot and cold pressures by drawing the cold supply from the cold cistern supplying the hot cylinder, otherwise temperature control at the shower mixer can be a whole hatful of headaches.

Combination cylinders incorporate a relatively small cold cistern, which would quickly be drained by a shower pump. The pump impeller can quickly be damaged if it starts drawing air. Most pump manufacturers recommend a minimum stored cold water capacity of about 50 gallons. The cold cistern of a combination cylinder is more like 5 gallons.

Even if the cold cistern is not supplying the cold feed to the shower, there's no guarantee it will be able to replenish the hot cylinder fast enough with the limited head available. This would lead to air being drawn down the open vent, and possible damage to the pump.

 

[Hugh Jaleak]

A pumped shower needs to draw its supplies from stored water, i.e. hot and cold water tanks. (You cannot pump from the mains suplly, highly illegal!)

With the Elson the intregal cold storage cistern is quite small, a shower pump would empty it very quickly and the incoming mains supply wont replenish it anywhere near fast enough. You then have a pump which will cavitate (wrecking pump) and whoever is in the shower could get scalded as the shower is only getting a hot water supply.

If mains supply is good a decent electric shower should be fine. Better performance may be obtained from the higher kW rated showers, (however these need a thicker supply cable), and any electric shower needs a dedicated supply/MCB from/in the consumer unit.

 

[Nat21]

Hi

Thanks first of all for the replys to my first question.

Since this isn't possible, what other options do I have if I replaced the water heater?

I'm currently looking at this water heater to improve the heating of the water, but also improve the pressure to the taps. The mains pressure is very good. So would one of these be ok?

http://www.ebay.co.uk/itm/290622182518?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1558.l2649

I really don't what to get an electric shower since the pressure of the hot water is very poor. From looking into these they wouldn't need a pump at all! It is a flat would this make any differance?

Any throughts?

Thanks
Nathan

 

[xr4x4]

You need a direct unvented hot water cylinder.

Mains pressure hot water...!

Then all you need is a mixer shower.

 

[dcawkwell]

Electric show much easier.

Alternatives are

combination boiler

unvented hot water tank. Mains pressure hot water no header tank needed.

Make sure you have approx 2-3 bar mains pressure and a flow of say 20 litres
a minute in order to give good performance.

 

[Dan Robinson]

Venturi shower (Trevi Boost as was).

Or switch the whole thing to an unvented cylinder and do it properly.

 

[Nat21]

Is the link I sent any good. Is this a direct unvented heater. What are the differance in vented and unvented and direct etc...

 

[Dan Robinson]

Direct are heated with an immersion.

Don't go there.

Unvented are mains pressure and have to be fitted by a professional.

Open vented are low pressure like you have now.