pumped shower on mains water

[RMIM]

Hi All,

(The following is outside the uk were water pressure, even water is not guaranteed at all times. UK bylaws are welcome but please say why they exist)

I’m having trouble getting consistent hot water from your typical electric shower.

The mains water is 1.5bar at best and the flow rate is (have to check, but I recall it was above the minimum printed on the shower).

Most of the time the shower/s activate (red light comes on and water heats) – but sometimes the light will not come on unless you start to fiddle with the settings and coax it into coming on. It’s very annoying.

I feel a shower with a built in pump might be the solution – however I have just cancelled an order for a Triton T150Z as it specifically says not to connect to connect it directly to the mains cold supply under any circumstance. Gravity feed only. I would like to know why?

There is actually a 900liter tank on the house – sadly the way it has been plumbed stops me from easily using it as per the instructions of the Triton T150Z. The tank is plumb so its output is actually fighting the mains water and pushing in the opposite direction (it can’t ever win as there is a oneway valve just after outside stopcock. So when mains pressure is high, taps etc get water from the mains. When the main cuts/low pressure the tank will push back the other way and water from the tank will reach the taps.

If the reason you are not allowed to use the mains to feed the shower is because the pressure might be too high and damage the shower – what if I used it in conjunction with a prv. (can low pressures get past a prv?) Or am I way off?

Maximum head stated is 10m (I looked that up and it said about 1bar).

Min head stated as 0.08m


Thanks

 

[simond]

So if it is outside the UK, why are you ordering a UK electric shower?

What is a 'typical electric shower'?

Sounds like the 900 litre vessel might be an accumulator.

 

[RMIM]

So if it is outside the UK, why are you ordering a UK electric shower?

What is a 'typical electric shower'?

Sounds like the 900 litre vessel might be an accumulator.

Thanks for the reply Simon.

It's cheaper here. They do sell the triton 80 there which is also pumped.

By typical electric shower I mean one without pump. One where the temp is adjusted by adjusting the flow.

Can you explain accumulator?

Normally the tanks here are connected to a 1.5HP pump that would serve the whole house. But as the tank has been connected this way, to add a pump to the main tank would require laying down a new pipe from the mains to the roof. That's quite a bit of work I was hoping to avoid by using a pumped shower.

Also available here are smaller pumps that you place just before your shower. But now I'm wondering if these are not allowed to be connected to the mains?

http://www.ebay.co.uk/itm/Electroni...-Water-Pump-Stainless-Steel-90W-/121822509605

From the diagram it seems connected to the mains. But it's not as tidy as having a single unit pumped shower.

Which is the best option?

 

[Madrab]

Ideally you go back to scratch and plan the plumbing out correctly to ensure no future issues, anything else is really just a fudge. To advise as best as possible, it would be good to have a picture of the tank setup. Ideally you would be taking a dedicated feed from this tank and connect a pumped shower to it if the mains cannot be trusted.

Pumping water direct from the mains is restricted to 12l/min in the UK to minimise any impact to other users.

 

[RMIM]

Thanks for the reply Madrab. I will have to get a better picture. I wanted to avoid running that long pipe. They have so many different types of pipes and fittings here, it's confusing.

 

[oilboffin]

The reason you can't pump too much from the main is if you pump too much you can collapse the main why do you think fire engines use hoses from the hydrants if you start to pump from the hydrant the hose will collapse (25years retained fireman)

 

[RMIM]

The reason you can't pump too much from the main is if you pump too much you can collapse the main why do you think fire engines use hoses from the hydrants if you start to pump from the hydrant the hose will collapse (25years retained fireman)

Thanks for the reply oilboffin

 

[RMIM]

So I have followed the suggestion of getting a proper pump - a mate was selling a 0.8HP pump so I took it. - All showers now work with no fuss. Great pressure at all taps.

The next thing was to buy an automatic switch. Not too familiar with them I just bought what I thought was the top model - It has an electronic bar readout. You can adjust start and stop pressure. After some fiddling I found a start pressure of 0.5bar and stop pressure of 5bar seemed to work. (I wanted to have a stop pressure of 1 bar or 2bar but the unit kept flicking on and off every few seconds. Had to go all the way to 5 bars to stop this from happening).The max pressure produced by the pump is about 6/7bars.

Everything seems to work fine, sadly there is a pressure drop of 0.1bar about every 3seconds! This then eventually activates the pump for about a second.

Why is this happening? Is it due to drips/leaks?

 

[magicmushroom666]

Should there be a one way valve after the pump, to stop the pressure acting back on the pump when its stopped? Might be the leak

 

[RMIM]

Should there be a one way valve after the pump, to stop the pressure acting back on the pump when its stopped? Might be the leak

Thanks for the reply magic.

The unit claims to replace the check valve (but it's in very bad English) - yet it tells you to place one before the pump which I have done.

I know I have some small leaks on some of the fittings - but does that account for the 0.1bar drop every few seconds?

 

[Nige F]

Looking at the accumulator tank - it seems to have a large screwed lid - reminds me of a filter tank from a swim pool ? Could this be what it is and the leak is around the screwed lid

 

[Madrab]

Yes, small drips on any of the outlets/connections can easily drop 0.1bar in secs.

 

[RMIM]

Yes, small drips on any of the outlets/connections can easily drop 0.1bar in secs.

Thanks for the reply Madrab.

I will have to tackle the drips.
In the uk we hardly need ptf tape. Here you can do ten turns and it's still loose.

What pressure drop should I expect if any when the system is drip free?

 

[RMIM]

Looking at the accumulator tank - it seems to have a large screwed lid - reminds me of a filter tank from a swim pool ? Could this be what it is and the leak is around the screwed lid

Thank for the reply Nige F -

The lids not even on. But it's not an airtight system anyway. There is even a tube that is open to the air. (I'm guessing it to purge air or allow air in so water can flow freely, preventing a vacuum behind it?)

I don't think if there is a leak before the automatic switch it matters - only after the switch? Not sure. But I can tell you there are leaks all over and I have found one at the back of the house.

Hopefully I can stop all the leaks and the system will hold the pressure.

I have run out of ptfe tape!