Author Topic: Electric shower, anything I can do?  (Read 12550 times)

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Offline IanB

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Re: Electric shower, anything I can do?
« Reply #75 on: July 28, 2019, 10:29:07 pm »
So, new house, has electric shower.  Shower has three settings, cold, low, high.

On low, when I turn it up enough to get good temperature, I get sod all flow/pressure.

On high, I have to turn it down to minimum or I get scalded and even then it can overheat and cut out occasionally.

So I guess this is because my upstairs water pressure is absolutely rubbish.  On low it uses a smaller element and when I turn it up it reduces the flow to make it hotter.  However on high there isn't enough water pressure to supply the element with enough flow to keep the temp reasonable.

I assume there is nothing I can do with that, like adjust the flow restrictor or something?

I'm planning on upgrading the whole heating system to a pressurized setup, so this is a temporary problem, but an annoying one!

The usual solution to low water pressure is to install an electric booster pump. Since UK houses commonly have a header tank in the loft to supply the water there is not enough head available to drive water through an upstairs shower.  The booster pump fixes this problem. Any competent plumber would be able to install one.
 

Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #76 on: July 29, 2019, 06:58:56 am »
The usual solution to low water pressure is to install an electric booster pump. Since UK houses commonly have a header tank in the loft to supply the water there is not enough head available to drive water through an upstairs shower.  The booster pump fixes this problem. Any competent plumber would be able to install one.

I have now come to the conclusion that the bathroom does indeed run off the mains.  I found the stop cock was partially closed, although opening it fully still didn't make the shower tolerable on HIGH mode but a new shower head did make it feel better pressure wise on LOW.

Anyway, heating engineer is calling this morning to give me my options for the upgrade.  I let them give me details  for both Combi boiler with on-demand tank-less hot water and also the system boiler with hot-tank that I can solar-ify later.
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Offline DTJ

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Re: Electric shower, anything I can do?
« Reply #77 on: July 29, 2019, 07:13:32 am »
Someone has probably already said it (bit I have not read all the replies....).

Try replacing the shower head with one with more flow (less back pressure). I think I have that right way around.

This seems to be a common fix with what we call 'instantaneous' hot water systems here in Australia.
 

Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #78 on: July 29, 2019, 09:49:50 am »
So to paraphrase the heating engineer.

"If you have plenty of money to throw at it and want to redesign your heating system, you can do whatever you want.  I recommend you go Combi boiler, it's easier, cheaper, more efficient and if you want to you can add a unvented reserve tank later for solar heating."

Basically the system boiler would add over £1000 to the installation cost.  Combi is circa £2700, system boiler circa £4000.

So I can later remove the electric shower and replace it with a power shower replumbed onto the hot water.  In the meantime there is a shower fitting on the normal hot tap which when fed from the combi boiler will be fine.
« Last Edit: July 29, 2019, 09:52:05 am by paulca »
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Offline SteveyG

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Re: Electric shower, anything I can do?
« Reply #79 on: July 29, 2019, 10:01:19 am »
So to paraphrase the heating engineer.

"If you have plenty of money to throw at it and want to redesign your heating system, you can do whatever you want.  I recommend you go Combi boiler, it's easier, cheaper, more efficient and if you want to you can add a unvented reserve tank later for solar heating."

I would be interested to see the evidence behind that statement. It's easier for the installer to put in a combi and offers greater profits. If it's a boiler replacement only, I would get additional quotes. Those are BG prices!

As mentioned before, I'd also suggest a heat only boiler over a system boiler if you choose that route over a combi.

What did he measure as the water parameters? (Flow, dynamic & static pressure etc)
« Last Edit: July 29, 2019, 10:03:27 am by SteveyG »
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Offline soldar

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Re: Electric shower, anything I can do?
« Reply #80 on: July 29, 2019, 10:15:26 am »
I'd also suggest a heat only boiler over a system boiler if you choose that route over a combi.

For the benefit of us, non-UKdians, can we get definitions of those terms? Just to make sure we are all on the same page.

And, yes, I find the prices of anything and everything in the UK absurdly high.
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #81 on: July 29, 2019, 10:20:17 am »
I would be interested to see the evidence behind that statement. It's easier for the installer to put in a combi and offers greater profits. If it's a boiler replacement only, I would get additional quotes. Those are BG prices!

As mentioned before, I'd also suggest a heat only boiler over a system boiler if you choose that route over a combi.

What did he measure as the water parameters? (Flow, dynamic & static pressure etc)

The cost of the tank for a dual immersion, single coil is £600-800 alone.  There is some additional plumbing required.

He measured the mains flow rate just which was 14 lpm, the combi boiler requires 10 minimum.

I'm still not sure what you mean by heat-only boiler.
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #82 on: July 29, 2019, 10:32:50 am »
I'd also suggest a heat only boiler over a system boiler if you choose that route over a combi.

For the benefit of us, non-UKdians, can we get definitions of those terms? Just to make sure we are all on the same page.

And, yes, I find the prices of anything and everything in the UK absurdly high.

As I understand them...
System boiler = a single out/return boiler that feeds through a heat exchanger coil in the hot tank before circulating the radiators, thus providing both hot water and radiators.  With or without the "S plan" diverter valves to switch between hot water only and/or radiators.

Combi = Combination boiler.  Provides an out/return for the radiator circuit and separately a direct inline on-demand hot water heater.  If you turn a hot tap on it immediately fires up and heats the hot water.  Turn the tap off, it shuts off.  There is no hot water tank or reservoir.

https://www.worcester-bosch.co.uk/products/boilers/explained
« Last Edit: July 29, 2019, 10:35:08 am by paulca »
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Offline SteveyG

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Re: Electric shower, anything I can do?
« Reply #83 on: July 29, 2019, 10:34:31 am »
I would be interested to see the evidence behind that statement. It's easier for the installer to put in a combi and offers greater profits. If it's a boiler replacement only, I would get additional quotes. Those are BG prices!

As mentioned before, I'd also suggest a heat only boiler over a system boiler if you choose that route over a combi.

What did he measure as the water parameters? (Flow, dynamic & static pressure etc)

The cost of the tank for a dual immersion, single coil is £600-800 alone.  There is some additional plumbing required.

He measured the mains flow rate just which was 14 lpm, the combi boiler requires 10 minimum.

I'm still not sure what you mean by heat-only boiler.

A system boiler has everything except the cylinder internal to the unit, so even if you just need to replace the diverter or pump, you have to disassemble the boiler to get to those parts (and also be gas safe...)

A heat-only boiler just has the heat exchanger and a flow and return to the boiler. You have everything else separate making it more customisable and maintainable . You can buy an Intergas 24kW heat-only for less than £700. System boiler comes in around £1100 and a similar (Intergas Xtreme) combi is close to £1800. Unless massive work needs doing, both end up around the same £2000-3000 in total.

The installer doesn't want the work if he's quoting £4000

More often than not, you will pay a premium for a system boiler over a heat-only boiler. Even after buying the parts separately.
« Last Edit: July 29, 2019, 10:36:26 am by SteveyG »
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #84 on: July 29, 2019, 10:44:30 am »
The installer doesn't want the work if he's quoting £4000

More often than not, you will pay a premium for a system boiler over a heat-only boiler. Even after buying the parts separately.

So looking at that link I posted:
https://www.worcester-bosch.co.uk/products/boilers/explained

A heat-only is what I currently have.  Including the header tanks in the attic and a vented, non-pressurized system which is just poor on terms of upstairs water pressure, in particular showers.

On the cost.  The boiler itself is probably around £1300-1600, installation is probably 2 or 3 guys over 2 days.  So the labour costs around going to be somewhere close to £800-1000 + addition parts, boiler control panel, radiator TRVs, 3 new radiators + fitting, etc. etc.  So £2700 ball park sounds about right.

Then add in the cost of the unvented tank which is £600-800 and we are already at £3500, so the plumber is only adding £500 for additional work for plumbing and setting up the hot tank.  The £4000 was just when I asked him for a finger in the air estimate if I was to choose system boiler.

https://www.screwfix.com/c/heating-plumbing/hot-water-cylinders/cat830956
« Last Edit: July 29, 2019, 10:46:21 am by paulca »
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Offline richard.cs

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Re: Electric shower, anything I can do?
« Reply #85 on: July 29, 2019, 10:56:26 am »
A system boiler has everything except the cylinder internal to the unit, so even if you just need to replace the diverter or pump, you have to disassemble the boiler to get to those parts (and also be gas safe...)

A heat-only boiler just has the heat exchanger and a flow and return to the boiler. You have everything else separate making it more customisable and maintainable . You can buy an Intergas 24kW heat-only for less than £700. System boiler comes in around £1100 and a similar (Intergas Xtreme) combi is close to £1800. Unless massive work needs doing, both end up around the same £2000-3000 in total.

So just to be clear, heat only and system boilers are functionally equivalent, the distinction is only in the detail of whether the pump and valves are internal or separate.

Combi boiler is on-demand water heating at mains pressure, plus heating a circulating loop for radiators. The actual implementation is usually that it has pump and valves internally like a system boiler and that hot water mode takes priority over space heating and circulates water from the sealed heating loop locally through a water-water heat exchanger to heat the mains pressure cold water.

Then add in the cost of the unvented tank which is £600-800 and we are already at £3500, so the plumber is only adding £500 for additional work for plumbing and setting up the hot tank.
The plumbing for an unvented tank is probably more similar to what you have now (vented low pressure tank) than the plumbing for a combi boiler is so I am very dubious about higher labour cost for unvented vs combi. Also a heat only boiler is cheaper than a combi (see SteveyG's numbers) by pretty much the price of the unvented tank. I'd tend to agree with him that the 4k quote is pretty high.

In my experience plumbers tend to push you in the direction of doing what they're familiar with. I'm not saying a combi isn't best for you, it depends on your use case, but it sounds to me like he's pushing for combi for his own reasons.
 

Offline SteveyG

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Re: Electric shower, anything I can do?
« Reply #86 on: July 29, 2019, 11:13:27 am »
In my experience plumbers tend to push you in the direction of doing what they're familiar with. I'm not saying a combi isn't best for you, it depends on your use case, but it sounds to me like he's pushing for combi for his own reasons.

Yes, both familiarity, ease and (depending on the manufacturer) heavy discounts to "accredited" installers.

Just to be clear, I am not suggesting any system is better for you than another - the use case should be entirely at the centre of the decision. Remember to account for the future too (additional family members etc).
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Offline Towger

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Re: Electric shower, anything I can do?
« Reply #87 on: July 29, 2019, 11:17:36 am »
If the hot water cylinder is more of less replacing like for like (with just original pipes/electrics moved/extended) £500 seem high for labor.  I have done this several times my self over the years. 

The going rate in Dublin is touching on €200 a day, wife has me spending 10K  :palm: on a new bathroom, pumps and plumbing etc...  I would expect the labor rates in NI to be cheaper, since they follow the money and most builders vans down here have NI reg plates!  Your labor rates will probably drop after 31st of October, if BJ and the DUP have their way.  The price of a cylinder has gone up with the price of copper.  Watch what happens to the old one, it will not be going into a skip  ::)
« Last Edit: July 29, 2019, 11:19:37 am by Towger »
 

Offline SteveyG

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Re: Electric shower, anything I can do?
« Reply #88 on: July 29, 2019, 11:25:20 am »
If the hot water cylinder is more of less replacing like for like (with just original pipes/electrics moved/extended) £500 seem high for labor.

There would be additional pipework for the PRV and expansion valve given the move to an unvented cylinder, but not much else.

Another thing to check would be if the installer is even G3 registered. He may not be, hence pushing the price high so that you do not go down that route.
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #89 on: July 29, 2019, 11:39:46 am »
Well anyway, I'm going to get another company to do a quote also. 

As to which system I want I'm still undecided.  If I wasn't considering the solar water heating at all, then it would be 100% combi.  The house only has me in it with the option later of my daughter spending the odd night here and there is always the potential of a partner later.  But the point is the hot water demand is small.  On an average day I maybe use 5 litres of hot water in the mornings washing, a handful of litres rinsing some dishes before they go in the dishwasher or washing my hands.  Every other day (yes, you can call me a smegger and judge all you want), a shower.  Thus storing a full tank of hot water would not be that efficient. 

That's compared to a busy family home serving up three or four showers a day and the odd bath.

The only thing leaning me towards a system boiler (or heat-only) is the ability to stick 1000W of solar on it and basically have free hot water with some of it taking a tiny bit of load off the space heating as a by product, although I haven't worked out just how much that would be.  Install of the solar system is around £1000 + whatever a spark charges me to check it for safety + the plumber cost to install the immersion.
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Offline SteveyG

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Re: Electric shower, anything I can do?
« Reply #90 on: July 29, 2019, 11:45:26 am »
Well anyway, I'm going to get another company to do a quote also. 

As to which system I want I'm still undecided.  If I wasn't considering the solar water heating at all, then it would be 100% combi.  The house only has me in it with the option later of my daughter spending the odd night here and there is always the potential of a partner later.  But the point is the hot water demand is small.  On an average day I maybe use 5 litres of hot water in the mornings washing, a handful of litres rinsing some dishes before they go in the dishwasher or washing my hands.  Every other day (yes, you can call me a smegger and judge all you want), a shower.  Thus storing a full tank of hot water would not be that efficient. 

Just as a reference point: Standing losses for a cylinder are usually between 35 and 55W depending on the cylinder of choice. So you lose around 1kWh per day if you use no water, or somewhere in the region of £10 per year. Worth also bearing in mind, heating a cylinder is more efficient than instantaneous heating of water as the boiler will not be operating at optimal condensing point.
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Offline richard.cs

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Re: Electric shower, anything I can do?
« Reply #91 on: July 29, 2019, 12:02:56 pm »
Solar aside, that sounds like a good use case for a combi.

But, if you did decide to go for the solar do you even need a gas heated hot water at all? I suppose if you want a new gas boiler for space heating the extra install cost is fairly low. You could alternately keep your existing boiler for space heating, get an unvented electrically heated tank for the hot water and spend the difference on a larger solar array so as to get free hot water for much more (potentially all) of the year. It depends how elderly/inefficient your existing boiler is and if you therefore want to change it anyway for more efficient space heating.

If you have a 60 L 45 C shower on alternate days, and otherwise use 10 L of 65 C water per day, then if your incoming temperature was 15 C your total heat required is well under 2 kWh per day, plus a kWh for standing losses. If you can angle your solar panels for best winter performance (south facing and about 20 degrees from vertical) then in Northern Ireland you should be able to get over 1 kWh per average winter day per kWpeak installed. More panel area needed if they just have to go at whatever angle your roof is. A 2-3 kWpeak install would give you free hot water year round and minimal maintenance cost with the gas boiler only used for winter heating. Your big problem would be if you had a future partner who likes 30 minute showers every day.
 

Offline soldar

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Re: Electric shower, anything I can do?
« Reply #92 on: July 29, 2019, 12:39:11 pm »
As I understand them...
System boiler = a single out/return boiler that feeds through a heat exchanger coil in the hot tank before circulating the radiators, thus providing both hot water and radiators.  With or without the "S plan" diverter valves to switch between hot water only and/or radiators.

Combi = Combination boiler.  Provides an out/return for the radiator circuit and separately a direct inline on-demand hot water heater.  If you turn a hot tap on it immediately fires up and heats the hot water.  Turn the tap off, it shuts off.  There is no hot water tank or reservoir.

https://www.worcester-bosch.co.uk/products/boilers/explained

OK, looking at that page, "combi" is what most homes here would have with the caveat that they need to be installed outside or take the air from the outside and vent the gasses to the outside.

The thing when deciding which one is the best option is that it depends a lot on what kind of use it will get. A family with a steady usage is not the same as a single person with irregular usage and that is different from a week-end second home.

I believe domestic hot water, heating, PV electric, etc are much better used and controlled in larger groups. They work well in large institutions like hotels, hospitals, etc. and compared to single home installations they would work better for groups of homes where it is much easier to balance production and consumption.
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #93 on: July 29, 2019, 12:43:10 pm »
If you have a 60 L 45 C shower on alternate days, and otherwise use 10 L of 65 C water per day, then if your incoming temperature was 15 C your total heat required is well under 2 kWh per day, plus a kWh for standing losses. If you can angle your solar panels for best winter performance (south facing and about 20 degrees from vertical) then in Northern Ireland you should be able to get over 1 kWh per average winter day per kWpeak installed. More panel area needed if they just have to go at whatever angle your roof is. A 2-3 kWpeak install would give you free hot water year round and minimal maintenance cost with the gas boiler only used for winter heating. Your big problem would be if you had a future partner who likes 30 minute showers every day.

I would be nervous about elevating the panels that much as it makes them into wind sails and we get 100mph+ gales every 10 years or so and 70mph gusts every year.  The surface area of a panel stood up nearly vertical in 100mph winds will need significantly strong mountings to not rip off and that moves the potential to ripping the roof off.  They even have strick regulations around them not over lapping the peak of the roof as it allows the wind to get under them and risk lifting the roof!

Maybe I can turn my DIY(OW) to other uses and use solar + a hot water tank and small pump and radiator, to take the cold and damp edge off the garage.  I can do this 100% DIY, especially if I can rescue my copper hot tank.  however is putting a few kWh of heating into the garage in winter going to make the slightest different when it's not lined, sealed or insulated?

EDIT:  Of course, due to me storing a bunch of stuff in the garage, I will probably need someway to at very least keep it above freezing.  Most people recommend sealing the edges of the garage door to stop direct drafts and using 2Kw oil filled radiator on a thermostat set to 2*C.
« Last Edit: July 29, 2019, 12:47:39 pm by paulca »
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Offline paulcaTopic starter

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Re: Electric shower, anything I can do?
« Reply #94 on: October 10, 2020, 05:37:09 pm »
Try the steam shower generator. You'll enjoy it for sure.

Is that on ali express or your website?
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