Going to take the plunge and get a high efficency gas boiler

Barack Obama wrote: »

Forgot to mention that I don;t think a combi-boiler would suit. The reason is that some of the bathrooms are a long way from the boiler and it would take a long time for the hot water to get to the tap - that's the way it is at the minute from the immersion tank anyway.

I'm open to suggestions - we have a pump electric shower only so this relies on hot water in the system.

Would there be an option available to re-locate the boiler more central for hot water distribution?

Even just putting a thermostat in the house to control the boiler would be more efficient than what you have at the moment.

Controls do make a heating system more efficient and the more of them you have the more efficient the system will be, and the way gas and oil is going I would be trying to squeeze as much out of it as possible.

How many zones would be normal for a 5 bed detched house? Was thinking 4 - d\s front and back & u\s front and back.

Install automatic radiator thermostats on every radiator and forget about inefficient zoning.

Each emitter (radiator) should be controlled individually. One gas pedal for speed controling for all cars in a certain zone would be called stupid, wastive. It's the same with the radiators in a house.
Controll them individually for as little as € 12.-to €15.- each. And increase the efficiency of the heating system by this.
This is how the majority of European central heating systems work. 'Zoning' is Irish, expensive, unreliable and inefficient. A job creation scheme for plumbers, payed dearly for by the consumer and the tax payers via the national trade deficit.

Barack Obama asks:

The more I ask experts, the more zoning seems to be a waste of money and I should get TRVs fitted to the radiators. Is this something I can do myself?

Absolutely, check the TRV manufacturer's home page, most have very good DIYer 'how-to-do-it' pages.

The radiators have to be installed and joined to the distribution system, the entire system then to be pressure proved. So the installation of the TRVs would be the heating system installer's job.
Which can be done on a DIY base as well, depending how handy Andy is

If
a.) installing a timer with the boiler and

b.) a minimum 'thermal draw' is always guaranteed there is absolutly no technical or economical reason for Irish 'zoning'. Then simply forget about it.
The 'minimum thermal draw' can be guarenteed by various ways: a buffer tank connected (wastefull, depending on the overall heating system), a radiator installed which is always open (frequently the bathroom radiator is chosen for this), the installation of TRVs which allow for a fixed minimum draw.

The smallest thermal consumer (radiator, buffer tank) determines the boiler's minimum outlet.
For example the smallest consumer consumees 2 kW then the boiler has to modulate from 2 kW upwards. The minimum output of the boiler should then be 2kW plus a bit for distribution loss.
This way no 'zoning' is necessary, each room now being an independant zone fully controlled.

Keep in mind that many posters here in the forum are not very up-to date, TRVs with a pre-set minimum draw some haven't seen, non-zoned CH heating systems are only know from home and Grandma's cottage.
Experience in modern energy management is hardly found since energy management is hardly tought anywhere on this Island.
As long as the consumer don't ask most plumbers don't bother to inform themself.

Was an energy demand calculation done ( EN12831) so far? What is the maximum demand for CH, a.)with and b.)without DHW?

DGOBS asks:

which boiler has a minimum of 2kw?

Here again the list which you should have copied and printed out:



http://www.boards.ie/vbulletin/showthread.php?p=75244837


Choice of boilers don't seem to be your strength, DGOBS. Have you asked Viessmann about their modulating condensing oil boiler - as promised?

DGOBS has a lot of questions concerning the laws of physics, so I try to help:

First of all, DGOBS, mark your questions with a question mark, being literate I find it easier to identify a question even if this question has hardly any structural grammar.

Like this one:

A) Available boilers to me is what I can buy locally, stocked by agents tht are here and provide support and warranty here, tht parts are available here, if I did as you suggested, what happens when they need a part, sorry mate it's minus 5 outside, your part I'll be here in a week or so!

I suppose the underlined part is a question, what " they" stands for isn't clear to me, but I give it a try:
Contact ELCO or whoever is there and ask them about sales conditions, about technical back-up. I'm not working for them and can't advise you on this issue. It is the non-idiots (greek term, no insult) who decide what to do and how to proceed.....

Second question of yours:

C) You have not answered any of the other questions raise bout interlock and demand

That is because I took them as being of a rethorical nature.

Third question of yours:

D) Have you ever actually installed and commissioned a heating system?

Yes.



Your 'expertise' is needed by gary71, he obviously does not know how a radiator thermostat works. He thinks they work in an on-off modus. Explain to him that and how TRVs work in a modulating modus, modulating between 1% and 99%.
You would not only do gary71 a favour by teaching him a valuable lesson but doing so should answer the questions you have asked about operating non-zoned CH distribution systems where TRVs are installed.

This is a method of learning, explaining a problem whilest asking a question leads to the answer. If practised by a half-ways intelligent brain tought to ask the question whilest looking at both sides of the same medal.

Now it is up to you to teach gary71 a lesson about the technical potentials of TRVs. And you'll see your own questions as asked above will be answered.