PigletJohn, may I please pick your brains?

[Fizzylemonade]

I am hoping that you can help me with some questions re a boiler and showers.

I live in a 4 bed house, with 2 adults and 2 children. We only have one shower which is in the en-suite and it is a mixer shower.

We have the original boiler which is 13 years old. It works fine at the moment but we are changing lots in the house and don't want to make a decision now about showers that we later regret when we come to replace the boiler.

We have always had combi boilers in the past in smaller houses so the hot water tank is a bit of a new thing for us.

We want to put a shower into the bathroom and were thinking of putting in an electric shower. We have mains fed cold water, under the sink we have a large blue plastic pipe which then connects to a brass reducer and becomes 15mm pipe. The pressure in the kitchen tap and elsewhere in the house is immense. If the tap is turned on too much it lifts the tap up.

We had builders here 18 months ago converting the garage and they used our hose pipe to mix mortar etc and told me that it was like using a pressure hose. In fact the outside tap leaks from the where the stem meets the nut and I think this may be to do with the pressure. It feeds off the kitchen tap pipework.

When I mentioned thinking of a combi boiler at a later date the builder told me to make sure that the new boiler was fitted with a device to control the water pressure on the feed into the boiler. Does this sound right?

We think we need to put a high kw electric shower into the bathroom to cope with the water temperature in winter as it is truly ice cold. Is this right?

Should we hedge our bets with keeping a mixer shower in the en-suite and an electric in the bathroom? The children are only 9 and 6 so don't shower in the morning yet and DH goes to the gym every morning so it is only me who uses the en-suite shower. No fighting for demand but if someone runs the hot tap I get a freezing shower for a few seconds. Certainly wakes me up

I would really appreciate any advice you can give me on this matter.

Thanks.

run the tap into a bucket, time it to full, see how many litres per minute you get out.

If you get a combi, it will break down sometimes, so an electric shower will give you a useful, though weedy or cool, additional source. No domestic electric shower has a heat output anywhere near a modern gas boiler (typically about 30kW for a boiler. An electric shower might be one third to one half). A 24kW electric shower (which you can't have) would need a 100Amp supply, which is equal to, or greater than, the main fuse in your house. Main fuses are often marked 100A or 80A max on the casing, but often contain a 40A or 60A cartridge.

If you have a cylinder (or a Megaflow or similar unvented, which would probably be very suitable as you seem to have good flow and pressure) then you can have an immersion heater in it as a standby for the boiler breaking down (less often if it is not a combi). If you buy a modern package from an upmarket maker like Viessmann, they can provide a high tech boiler and unvented cylinder combination, possibly with weather compensation and solar input - you need an approved installer with extra training and experience to design it.

A modern combi boiler will cope with higher pressures than are usual in the UK, I can't see the need for a pressure reducing valve but you can have one if you want.

I am guessing that you currently have a cold water tank in the loft. The cold water feed to your mixer shower should come from this, and not at mains pressure. If the mixer shower goes cold when someone turns on a hot tap it is probably dur to poor pipe run design. You can get a presure balancing shower that is supposed to cope with it, Aqualisa did or do make one, but it is only supposed to handle small variations.

If you have taps that leak, it is due to poor fitting and the joint needs to be taken off and remade. This should be very easy for a competent plumber, though it is true that high pressure will make it worse.

Thanks for that it is really helpful.

We have 2 tanks of water in the loft both very small, the plumber who came to put in radiators in the garage conversion said that one was for the central heating system and the other fed the hot water tank. I asked as I don't like being unknowledgeable about my house.

The pipes for the mixer shower are all under the boards in the loft so I don't know where they feed from but the force of the shower is really good even in snowy weather and minus 6. I love the mixer shower as they can look very beautiful, not mine at the moment, it is white plastic. I only like the idea of the electric shower for the bathroom as it is for the boys and if the boiler breaks I can still shower (previous experience of this in the past)

I like the idea of the megaflow, will do some research. I was worried with you posting a moving house thread that you would be very busy and then disappear and I wouldn't be able to ask you about this stuff We like the idea of solar as our house is on a north/south axis. My Grandad had a solar water heater but he recently died so I didn't get chance to ask him about it all.

Our concern is that we heat a huge tank every day, once in the morning as it is a green foam insulated thing (2 years old as it was leaking when we moved in so it was replaced) so retains its heat but we don't use all the water. Our gas and electric use is less in this house than our previous much smaller 3 bed because it is a much better insulated house so I am not overly concerned. I just hate waste.

Re filling a bucket, I will definitely do that to check flow, like I say I hate waste so I would need to be able to do something with that water. As it has rained for 2 weeks I don't need it for my veggies.

Thanks for sharing your extensive knowledge.

modern hot water cylinders are very well insulated and if heated up and left hot, they lose (depending on who you believe) between 0.5kWh/day or 2kWh/day in heat leakage. That's between 2p and 8p worth of gas per 24 hours. It also helps to lag the hot pipes with Climaflex or similar. You can put one or two red insulating jackets around even a factory-insulated cylinder if you have room, it will cut heat losses slightly more. Due to temporary energy-saving subsidies, you can buy jackets for £3 at the moment, so I'd certainly put two round a plain copper cylinder.

If you run the boiler HW on a timer morning and evening, it will prevent the boiler running repeatedly for short periods each time you fill a sink, which is inefficient. Cylinders usually hold about 100 litres of hot water (about a bathfull) so let the boiler run before and during the times you will be having baths and showers, and it will stay hot the rest of the time. A modern boiler will take a modern cylinder from cold to hot in about 20 minutes so you can set the timer to come on half an hour before you get up in the morning or get home at night.

It sounds as if the cold supply to your shower might be at mains pressure, this is incorrect as it will overwhelm the low-pressure hot from the tank, unless there is a balancing valve on the cold supply to the shower, and is liable to lead to cold water leaking past into the hot pipes and making the cylinder supply tank overflow, especially if you have a ceramic mixer which is prone to this.

Thanks again, I think as the hot water tank has been very good to me I shall treat it to a brand new coat.

I shall reset the timer slightly for the hot water coming on, it is programmed to come on just before I jump in the shower but I shall adjust it so it is on whilst I am in the shower.

I am a sahm so am home a lot in the day, the hot water seems to stay very hot when I handwash my son's lunch box after school, and for the bath or shower in the evening for the boys. I take my bath in the day, no one tries to get in then.

I shall investigate where the cold water supply for the shower comes from.

I think I miss my old combi boiler because I had a digital honeywell thermostat that meant I could set the temperature for different times of the day. The one here is just a manual dial thing. On the digital one we had it turned to a much lower setting in the night, boost it right up for when the children got up and reduced it down again for the rest of the day.

I shall research the company you suggested. Again, thank you.

you can fit a programmable room thermostat to replace a plain wall stat. They tend to cost around £60. They normally fit straight onto the existing wires. Wireless ones are available at higher cost but IMO more likely to go wrong.

Piglet John,

Where are you based and do you do this kind of work professionally? You are so knowledgeable and so good at explaining stuff that I think you should a) help me renovate my plumbing and b) be on the telly.

our very old combi boiler packed up last week & I wish we had an electric shower!

no, I'm far too lazy to do any work myself.

oooh I am a bit mad now, I had the screwfix catalogue in my hand when the spark was here and he didn't tell me I could have that. Admittedly my last one was wireless but I just wanted something where I could set the temperature without having to walk downstairs into the hall at 5.30am and turn the dial up.

Do you know, I have never had a MN crush before, but I think PigletJohn is just flipping amazing

So I currently have this in the hall, and then I have <a class="break-all" href="http://www.google.co.uk/imgres?q=landis+and+staefa+rwb9&hl=en&safe=active&biw=1536&bih=813&tbm=isch&tbnid=ibIit6Niy_rCnM:&imgrefurl=recommendations.ebay.co.uk/Siemens-RWB9-7-day-Programmer-Central-Heating-timer-Hot-Water-/MESMR%3F_pvtid%3D200701957595%26_category%3D20598%26_trksid%3Dp4340.m0&docid=l1g7TrD5zMfRKM&itg=1&imgurl=thumbs3.ebaystatic.com/m/mFVEIYEu0n7jiuL8qUPyMGQ/140.jpg&w=140&h=83&ei=GP-XT8KCOqOt0QWp1dneBQ&zoom=1&iact=rc&dur=694&sig=109607027754493980800&page=1&tbnh=66&tbnw=112&start=0&ndsp=28&ved=1t:429,r:11,s:0,i:88&tx=77&ty=27" rel="nofollow" target="_blank">teeny picture of it in the kitchen which allows me to set the times the heating and hot water come on.

So I can replace the hall thermostat with something like you suggested? I may just cartwheel to school.

Ponders we went 3 days without heating February time many years ago due to kitchen being fitted and they turned off the gas as there was no valve to isolate the gas hob. I was also 5 months pregnant, I was not a happy woman.

Mad dash to school now in the pouring rain