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Can anyone explain plumbing to me in teeny tiny words?

(17 Posts)
BazHasUnfortunateEyes Tue 23-Aug-16 06:51:08

So we're buying a house with a water tank in the bathroom which I want to take out.
We are going to have the house re-plumbed as it has ancient radiators (no thermostats) and an unheated conservatory.

We have a megaflo (no idea what this is!) in our current house which is in the airing cupboard. We also have a boiler downstairs in the utility room. Hot water supply is v good and consistent, you can flush the loo while someone is showering with no effect etc.

What is a combi boiler? There is plenty of space downstairs in new house (where boiler is - a small annex off the kitchen) could everything go in there when we replace the system?

Sorry for the comprehensive lack of understanding, please do not underestimate my ignorance on this, simple answers please!

BazHasUnfortunateEyes Tue 23-Aug-16 06:51:54

Oh and what is the megaflo and should we have one again?

Footle Tue 23-Aug-16 06:55:10

PigletJohn is your man. Let's hope he will be along soon to explain it all in magnificent simplicity. His call out charge is very reasonable.

00100001 Tue 23-Aug-16 07:01:40

You won't have a mega flow and a combi I'm the same house.

This will give a brief intro

Ifailed Tue 23-Aug-16 07:13:25

I'm no expert, but a combi boiler heats water on demand - there is no hot water tank to store heated water. So, if you turn on a hot tap, it jumps into life and heats up cold water as it flows through the boiler and delivers it to the tap. Likewise, if your timer/thermostat says warm up the water in the central heating, it fires up.
A big bonus is there's no water tank taking up space, and you only heat up the water you need, so should save energy. Downside is, unless the boiler has the capacity to heat up water quickly enough to satisfy someone showering, the central heating whilst someone else is running a hot tap somewhere, everyone gets luke-warm water.

A megaflow is a hotwater tank. It can be heated by the existing gas boiler (not a combi), and also by an internal electric element (think wacking great big kettle).

BazHasUnfortunateEyes Tue 23-Aug-16 07:23:55

That's a useful link 00100001, thanks!

Reading that link it might be useful to provide a little more info.
House is 4 bed detached, not mahoosive but not small either.
There will be two bathrooms (one family, one ensuite) and a downstairs loo (toilet and basin only)
There will probably be times when we need two showers running at once but not all the time (DC tend to shower in evenings, dh and I shower in morning).

Can megaflos be situated downstairs or do they need to be upstairs for purpose of flowing downwards?!

I do like that we don't need pumps for the showers, my parents have a pump in their shower and although the water flow is good, it's really noisy. I really want to avoid that if possible.

BazHasUnfortunateEyes Tue 23-Aug-16 07:25:53

Ifailed - thanks for info! Would the lukewarm heating apply when other appliances are on like dishwasher/washing machine or do they self heat? I'm so embarrassed by my ignorance blush

PigletJohn Tue 23-Aug-16 07:28:37

A few tips:

Unless you have a cold water storage tank, the amount of water coming out of the taps (all the taps added together) at any one time cannot exceed the amount of water coming into the house through the supply pipe. This is the flow.

In older houses the supply from the main under the pavement is usually a half-inch or even 3/8" pipe in lead or steel, or a 15mm pipe in copper. You can get an idea of how much flow it delivers by filling a bucket at the cold tap at your kitchen sink, and at the garden tap if you have one, timing it, and calculating how many litres per minute you get. It will probably not be enough.

Lead pipes last about 100 years, sometimes 2000, steel pipes last about 40 years. It is difficult to predict reliably when they will start to leak. If you are upgrading your plumbing it is usually a good idea to replace the supply pipe in 25mm blue plastic, or 32mm which costs little extra, all the way to the water meter under the pavement. Fit full-bore stop valves or you will be constricting the flow (some plumbers little ones as they are cheaper). If you are contemplating replacing the pipe, and it is lead, get the water co to test the drinking water for lead content well before you start. There may be a lead replacement subsidy or they may connect the new pipe at a reduced price. If you don't do it now, then one day, you will wish you had.

Try the flow test in your old house. Then fill a bucket at the hot tap and the cold tap on the bath. It will probably be more flow. Consider that a bath holds about 100 litres of water, and calculate how long it will take to fill.

Flow is not the same as pressure.

It is useful to know that energy from electricity costs three or four times as much as energy from gas.

If you have a hw cylinder with one or two immersion heaters in it, you can continue to have hot water when your boiler breaks down.

Combi boilers break down more often.

Solar heating of hw is not an economic proposition unless you have no gas.

GingerAndTheBiscuits Tue 23-Aug-16 07:40:32

Thanks for info on flow PJ - we need to replace the main from the street to house and it's useful to know what to ask for

BazHasUnfortunateEyes Tue 23-Aug-16 07:44:48

Thanks pigletjohn! Very interesting, I think I thought flow and pressure were the same thing blush

Funnily enough, the surveyor has also recommended having the mains connecting re-done for exactly the reasons you said. The property is almost 100yrs old and he was concerned about lead piping too. Hadn't thought about getting water company to subsidise it though so we will get the water checked for lead when we move in.

So in terms of the size of the house and not wanting pumps for the showers, will a megaflo be the best option again (presuming flow into new house is reasonable?) If it is, can we have it downstairs?

Ifailed Tue 23-Aug-16 07:45:56

you can get appliances that will use the hot water supply, but they are quite rare, IMHO. But as modern washers are very efficient nowadays and use quite little water, there's little point.
Combi boilers are great in the right place, however having lived in a houses with a combi and a traditional boiler c/w hot water tank, I'd choose the latter, especially when the boys were younger and seemed to need constant baths. Plus, as PigletJohn points out, with a megflow type hotwater tank, you can still have hot water if the boiler dies. Which of course always happens on a Saturday morning during a snow storm.

BazHasUnfortunateEyes Tue 23-Aug-16 07:52:23

grin@Saturday morning snowstorm. Or Christmas Day. I know more than one person that has happened to!

My main concern is not having a tank upstairs if possible. There just isn't room. I know hot water tanks in the loft are generally a bad idea (I know this because pigletjohn said so on another thread I was reading lol!) which is why I wondered about the megaflo downstairs.

Ifailed Tue 23-Aug-16 07:58:09

The reason for having a HW tank upstairs, is gravity will help send water to the rest of the house, but as it is pressurised (hot water expands), you can put them anyway, in theory. Best to get some advice though - likewise confirm the incoming flow is sufficient.
Although H/W tanks do take up room, in does mean you can have an airing cupboard, which I think are wonderful, especially in the winter (plus they are a great place for homebrew!)

PigletJohn Tue 23-Aug-16 08:02:21

You can put an unvented cylinder (Megaflo is just a brand name, like "Hoover") downstairs. People usually get about twice the size of an old cylinder, so about 220 litres (220l of water weighs 220kg) so they are heavy. If it is close to the hot tap you use most, there is a speed and a very slight economy saving. Please don't put it in the loft. Insulate the pipes. It has to be accessible for inspection and servicing, this can be done with the annual boiler service if the person has the G3 qualification.

It is very well insulated so it will not make the airing cupboard very warm. This is a Good Thing. You will probably get more heat off the hot pipes than the cylinder.

With any cylinder, you can, if you wish, have a towel rail or radiator connected to the circuit that heats the cylinder, so it will warm up during and after running a bath or shower, provided the timer is on. This can be very convenient. Be sure to have TRVs fitted so that you do not waste heat, especially in summer.

boilers are less economical if they are frequently starting and stopping, so for best economy, set the boiler to run for about half an hour or an hour morning and evening (modify according to your experience). A full cylinder will do several showers or a couple of baths. It will not go cold during the day or overnight due to the good insulation. When the cylinder is hot, the boiler will stop trying to heat it.

BazHasUnfortunateEyes Tue 23-Aug-16 11:03:47

Thanks you two, that is excellent info all round.
Is there nothing mumsnet can't help with?! grin

PigletJohn Tue 23-Aug-16 11:20:22

next weeks lottery numbers

Solving Brexit.

BazHasUnfortunateEyes Tue 23-Aug-16 12:33:43

True but we can live in hope...

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