BEFORE YOU BUY - Plumbing advice

ListysDad

This thread is designed to help YOU the poor consumer. It's a list of Do's and Don'ts to consider PRIOR to buying anything connected to plumbing.

Mods - Can you make this a sticky please?

Taps
Not all taps are created equal. Traditionally in UK housing we have low pressure hot water systems. These are identified by the fact that you have a hot water cylinder and a large tank in the loft that you can hear filling when you run hot water off. You will have what is termed a high pressure hot water system if you have a combi boiler, an unvented cylinder or a thermal store.

When buying replacement taps you have to be careful that you buy taps that are suitable for/compatible with the type of system you have installed. If you have a high pressure system you can have just about anything BUT if you have a low pressure hot water system then you must be VERY careful about what you choose.

Pressure is measured in Bar. A pressure of 0.1 bar equates roughly to raising a tank approx 1m above where you want it to come out with NO bends in the pipe and the pipe being 15mm copper.

Ideally, when you have a low pressure system you are looking for taps that work well with 0.1bar. A bathroom is typically on the top floor of a property with the tanks just above the ceiling in the loft. This gives a 'head' (height from the tank bottom to the tap itself) to the sink or bath taps of just over 0.1bar so it's just over 0.4 bar to the kitchen taps if on the ground floor. The reality is that it's less usually because of bends and fitting in the pipework.

Many taps now 'say' they are suitable for low pressure. Unfortunately there is no official definition of low pressure so it most often means a minimum pressure required of 0.5bar! This means you will typically have poor flow in the kitchen and appalling flow in the bathroom...

For low pressure taps you need to ensure it is 0.1bar to guarantee decent flow rates everywhere.

More subjects to follow.

Ask if you want more info.

keystone

Just to add to the above. When buying the modern style of tap you specifically need to ask the salesperson what flow rate they will deliver in litres per minute based on your description of your hot and cold water supply configuration. "Works down to 0.1 bar" is neither relevant nor useful nor helpful. Don't be fobbed off with it.

Cheers

Canucklehead

Hi: for folks who aren't aware/haven't seen my previous links, the Bathroom Academy has produced an excellent series of free guides for all things bathroom related...get them here. The HHIC has great info on all things heating and hot water related....more here. And last but not least the Gas Safe Register.

HTH

Canucklehead

P.S. And of course the CIPHE.;)

ListysDad

Pipes are insulated for two basic reasons:

1 - To reduce heat loss

To prevent heat loss any insulation you fit will do A job. The thicker the insulation the less heat you'll lose. The more pipe you cover the less heat you lose too, so fitting it so there are no gaps is the most effective way it can be fitted.

When looking at reducing heat loss like this you can fit either polyethylene (grey) or nitrile (black (rubbery)) based products as they each perform well. From about 25mm of wall thickness, you get little additional saving for the additional cost. In a pure heat loss control situation like this, it's also quite OK to use insulation tape every 300mm to close the gaps.

2 - To prevent freezing

Firstly let's look at what happens when pipes freeze. Oddly enough, its not the physical freezing of the pipes that causes a burst. A burst normally happens when the third ice plug form in the pipework. The first two plugs form without incident but when the third begins to form the pressure of the water inside the pipe between the plugs rises extremely quickly up to 250bar or over 3600 psi! As copper pipe will only cope with 33bar or 280 psi it's no wonder it bursts! It's this literal explosive violence that gives a burst pipe its traditional flared look.

Unlike stopping heat loss, if you wish to stop freezing you cannot leave any part of a pipe open to atmosphere. To do so means the little heat that's there will simply leak out as heat always travels from hot to cold.

So, having now realised that protecting against heat lost and freezing are not quite two sides of the same coin we have to understand how to protect our homes.

The choice of material is critical. Polyethylene (grey) insulation cannot protect your pipes from freezing. Although cheaper, this type of material starts to shrink at 4 degrees celcius that way above freezing and its shrinkage rate gets worse the colder it gets. This means therefore that your carefully installed insulation has massive holes in it by the time it really matters so lets you down.

Let's make one thing clear here. There is not a manufacturer of this stuff anywhere in the world that sells it for freeze protection; not one. The fact that you can go to a shed or even a plumbers merchant and ask for something to protect your pipes against freezing and be given the grey polyethylene is simple ignorance. Until very recently, until I intervened, even Govt advice pictured the grey insulation that will now change.

The only insulation suitable for domestic pipe insulation is a nitrile based product such as Armaflex or Tufflex or similar. The product must be installed with a MINIMUM of 25mm wall thickness (more if in a well insulated loft) and EVERY joint must be glued with the correct adhesive and NO gaps should be left.

Below are some images of what before and after should look like.




Anyone any idea why the images aren't showing?

As they say a picture is worth a thousand words!

Lastly, insulation itself DOES NOT prevent freezing. All insulation does is slow down the rate of heat loss so short periods of very cold can be tolerated. If you want complete protection then the heat being lost from the pipework should be replaced by what is called trace heating. Its typically a self regulating heat tape that is installed INSIDE normal insulation. Just a note here. When trace heating is installed its typical for the wall size of the insulation to be reduced so the tape doesn't overheat. It's NOT a DIY job.

Hope that all helps someone.

BTW Before anyone says anything about the Water Regs, let me tell you here and now THEY ARE WRONG. Email me if you want more information.