Boiler solution for use with a Thermal Store

[marshalln]

With the horrendous price of oil recently I'm looking at replacing oil CH with gas, we already have gas to the house. We normally use about 2000L per year but the last year has been quite a lot higher with the cold weather.

The current system consists of a vented 20kw boiler feeding a 2 coil thermal store, 1 pump on th boiler loop, 1 on the radiator feed, all radiators have individual thermostats, 1 room stat in the hall and mains pressure hot water off the second coil in the tank. From various discussions it looks like Valliant, Bosch Worster and Viessmann (Vitodens 100W Compact 24kw looks a reasonable choice) are the front runners in choice of boilers.

What are the best bells and whistles (Weather compensation ?) to add to the system to improve efficiency and reduce running costs. WC looks like a neat idea but not sure if it could add value with a heat store which should to be kept at a constant temperature to supply hot water to the taps.

 

[Agile]

The Viessmann 200 is designed to heat a cylinder ( or store ) as a priority and to then revert to heating only with weather comp.

There is a bit of a problem with water heating because the storage temperature of the store is usually designed to be around 80 C which is higher than the boiler will deliver efficiently.

A better solution is to have an unvented cylinder which is heated to the desired 55/60 for which the boiler is mostly condensing.

Tony

 

[Norcon]

Defniately retain the thermal store. Especially if its already supplying your hw requirements.
The minute saving from a boilers condensing operation should never be an incentive or reason to remove an operational system.
Which incidentallly can be easily modified to increase hw production whilst lowering the set point temperature.

 

[Gasman77]

The Viessmann 200 is designed to heat a cylinder ( or store ) as a priority and to then revert to heating only with weather comp.

So is the 100 Tony, just in case you were not aware

 

[Tibbot]

The oil price is now falling (from 77p to below 60p/l in 10 days) and should continue to do so. Gas prices also go up and usually stay up. If your decision is only financially based, I think you'll be making a mistake.

 

[snb]

without the details of how big your house is and how old the boiler is , i would be wary of jumping to gas. If you aim to buy your oil each year between march and sept then you will generally pay a lot less.

Oil boilers are generally very efficient . non condensing 70% to 90% and condensing 88% to 97%.

Best gas condensing is around 91%

Often oil boilers are too big for the house or cylinder used and down rating them is very easy.

For the cost of a gas install you can buy a lot of oil and the oil boilers last a lot longer than gas.

 

[snb]

without starting a slanging debate mysteryman perhaps you could enlighten everyone to what is opinion.

I gather your understanding of oil is limited!

 

[marshalln]

So that people don't get the wrong idea about what this site is for.

Anybody who wants to do any public slanging can go elsewhere. If anybody has something factual to say then back it up with references where possible. Any other statements will be treated as opinions unless they are backed up by a number of contributors which will tend to add more weight to the statement.

Apart from that thanks very much for your ideas.

 

[marshalln]

AFter my last post I thought I'd look at the Which website, trying to be careful and not steal there thunder. BTW you can get a 1 month view for a £1.

The best oil boiler has a measured efficiency of 91.8% (a 26kw combi cost ~£2200) and gas is very similar (at 90.3% 24kw ~£800)

 

[Boilerman2]

I Suspect that "Mysteryman" is an Employee of Viesmann??

 

[silverback18]

I Suspect that "Mysteryman" is an Employee of Viesmann??

Or its just HIS OPINION that Viessmann are good boilers.

 

[simond]

So that people don't get the wrong idea about what this site is for.

Anybody who wants to do any public slanging can go elsewhere. If anybody has something factual to say then back it up with references where possible. Any other statements will be treated as opinions unless they are backed up by a number of contributors which will tend to add more weight to the statement.

That's a nice idea, where did you get that from?