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HELP !! Should I change a one pipe heating system ????????

Postby algazz18 » Wed Mar 05, 2008 7:11 pm

I have recently moved into a bigger house and It has a old heating system with tank in loft and hot water tank in cupboard the boiler is working ok (is not a combi)
Had my first bill in and my gas usage is nearly double what I used to be in my old house where I had a combi boiler.
Do you think my usage could be due to old system which should be upgaraded to combi or would It be too costly?
I have no idea and have had different opinions from 2 seperate plumbers and now been told the central heating is a one pipe system.
I do not know who to believe or what to do.
Please help me
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Postby kevarch » Fri Mar 07, 2008 11:37 am

a one pipe system is very inefficient and costly to run especially in large houses. they are most definitely not suited to a use with a combi boiler whatever a plumber might tell you. in my experience most plumbers don't have a clue about one pipe systems.
first of all be sure that you have a one pipe system; a clue to this is if the last radiator in the run is considerably colder than the first
if you are happy that your existing boiler is up to the job then your best plan is to keep that and upgrade to a two pipe system. depending on the size of the house this should be much cheaper than replacing the boiler but it will cause a lot of disruption as all the floorboards etc have to come up.
this should warm the house better and reduce your heating bills if your present boiler is efficient
hope this helps
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Postby kevarch » Fri Mar 07, 2008 11:48 am

further to my previous reply click on the link below for a basic explanation of one and two pipe systems ... ystems.htm
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Postby Perry525 » Fri Mar 07, 2008 12:43 pm

Alyson, there is a lot that people can say about your system, mostly to encourage you to give them work and spend your money.
There is not a lot of difference between heating systems when it comes to the final bill. ie; Cost of buying and running say over five years. Against keeping your current system, with its perhaps higher running costs, and how much it ends up costing you over the same five years.

Having said all that, lets try a quick education to answer your questions.

A single pipe system. The hot water goes from one radiator to the next cooling as it goes. The hottest radiator is closest to the boiler.

With a twin pipe system, the hot pipe goes to each radiator in turn but, the return water goes into a separate pipe that goes back to the boiler to be reheated. So there is little difference in each radiators temperature.

A twin pipe system, enables radiators to be turned off and to have thermostat valves.

However, the more pipes you have the greater the heat loss from the pipes.

Combi's, there's a lot of advertising about these boilers, they are portrayed as being wonderful, in truth they are not suitable for everyone.
So much is made of the fact, that at start up they extract waste heat from the exhaust gas, that only lasts for a few minutes, then when the home is heated and running normally the 20 C degree difference disappears and they are the same as the one you have now.
Another very important point, they are difficult to live with if you have a family.
And very important. If you have a baby or young children. They have no back up store of water. If your water is cut off by design, work on a pipe up the road, or more likely cut because of an accident. You have NO WATER! You may be forced to drive to find an open supermarket and buy water to flush the toilet or wash yourself or the children.

When they do work, they only deliver water to one tap. If you live with someone who turns the tap on while you are showering you could be standing there soapy and no water.

The biggest problem when heating a home, is the wind. The wind blowing past and over a home, sucks the air out. Usually, the warm air you have paid to heat.

Your first priority is to go round and find every hole. Every gap round windows and doors to the outside, block them. Where pipes and things go through walls block the gaps. Check the upstairs light fittings, they are often badly fitted with nasty holes through the ceiling.

Once the holes are sorted, then check the insulation on the hot tank, pack as much insulation round it as you can find, old blankets work fine.

Check the upstairs ceiling in the loft, is it insulated? If so with what? And how much. If its fibreglass, is it in a plastic bag? If its not, the heat will just rise through it.

Hope thats of some help. Best of Luck
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Postby iansavell » Mon Mar 10, 2008 2:46 pm

Was searching for a solution to a different problem but thought I would correct some misconceptions about ventilation, insulation, water supply and combi boilers.

Ventilation: Don't go sealing all gaps. Some ventilation is required for a healthy house, e.g. to disperse fumes, cooking odours, moisture from the air you breathe out etc. Aim for about 20-30 litres of air changing every second (about 3 complete air changes per hour). There is actually very little heat in the air in your house, it is mostly in the floor, walls, furnishings etc. This is because those things have much more mass than the air.

There is a wonderful scenario in "the day after tomorrow" where a sudden drop in air temperature freezes a building in New York, except for a small area kept warm by burning books. No. It can't happen!

Insulation. Heat does not rise through unbagged loft insulation. Unless you don't have a ceiling! Insulation is bagged to avoid contact with irritant fibres during laying. (but as afterwards it is sealed away in your loft it won't continue to irritate you)

Water supply; The tank in your loft is, in most reasonably modern houses, simply a header for the hot water cylinder. All cold taps and toilets are fed directly from the mains and are dry if the main supply is interrupted. In the event of an interruption you should not drink the water from the hot tank. Look at the state of your header tank and ask yourself, would you want to drink from it?

Combi boilers: If the boiler is adequately specified it should supply all your hot water needs. Also as the feed is mains pressure you may, especially in a bungalow, get a much better hot water flow rate than with a header feed system. Finally, if you have a family who like a bath now and then, a combi boiler will provide hot bath after hot bath after hot bath. A tank will supply one bath if you are lucky. After that you have to wait for the whole tank to reheat.

Heat recovery: Effective all the time the boiler is on, but that applies to any modern boiler, combi or not. However, with a hot tank system you are paying to heat water you might not use and to keep water hot until you need it

Yes, combi boilers are not for everyone, but at least get the facts straight.

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