Central heating upgrade

[Dave Plowman (News)]

Many are a bit like a car injection system complete with Lambda sensor in the exhaust, so the fuelling is closed loop.

[Doctor Drivel]

This man is a pure plantpot, not understanding the basic of heating systems or boilers. But this is the Internet, so plantpots have their say.

[Doctor Drivel]

This man is a barking mad plantpot. Do not take any notice of him. He needs teatment.

[Doctor Drivel]

This man is a barking mad plantpot. Do not take any notice of him.

[Doctor Drivel]

Older systems were designed to run at 80C flow, 70C return temps. This was to prevent the boiler from condensing which can rot the insides of an old boiler. They are designed to keep the house to design temperature at -1C to -3C outside temp. So in most cases as it is not -1C outside the system is running on part load. That means the rads are bigger than required to supply the design temperature at say 10C outside. A condensing boiler with a good control system can take advantage of these oversized radiators in average use.

The control system keeps the return temperature as low as possible to maintain the house design temperature. There are many ways of doing this. One good method is to have an integrated weather compensator with room temperature influence. This modulates the boiler burner down or up to the outside temperature. If the house is still too hot, as a room sensor detects, then the burner will modulate down even more.

This ensures very low return temperatures promoting high condensing efficiency the vast majority of run time. As the rads are sized to run at

80C, for an old system, when -1C outside the efficiency will be low when so cold outside, but the room temperature influence will still modulate the burner down to a degree.

As more insulation is added to a house and draftproof double glazing, the radiators then are oversized, so making them larger and ideal for a condensing boiler's efficiency. You gain all around, by adding a modulating weather compensated condensing boiler, and insulation. The extra insulation reduces fuel usage and make the system more efficient too.

[Doctor Drivel]

She has had either cowboys fit them, and/or bought cheap crap. "Quality" condensing boilers fitted and maintained properly will last 30 years.

There maybe crud in the system Fit a plate heat exchanger across the flow and return and fit a quality condensing boiler on the other side to isolate the boiler from the crud which can do damage to a boier, even old boilers.

If the boiler model had an upgrade to full electronic ign, many did, then buy that control system and fit.

[Roger]

The message from "Doctor Drivel" contains these words:

Dribble is the perfect example of the moronic newsgroup poster. I ask him a simple question and being unable to answer it he snips the question and resorts to abuse.

Dribble, you claim to know much about central heating systems, so why is it you can't answer the simple question which I have helpfully repeated below?

Just answer this simple question:

What is the return temperature required to achieve maximum recovery of the latent heat?

[Roger]

The message from "Doctor Drivel" contains these words:

Many? Do quote them all, or is your counting system one, too, many. :-)

Clear as mud.

There is an old adage that Dribble frequently ignores - if you are in a hole stop digging. Now it seems he has a boiler with a similar problem. "If the house is still too hot" it only makes matters worse if the boiler continues to fire.

[Doctor Drivel]

You are clearly a lunatic. Please get therapy.

[Doctor Drivel]

This man is a pure plantpot, not understanding the basic of heating systems or boilers. But this is the Internet, so plantpots have their say.

[Roger]

The message from "Doctor Drivel" contains these words:

Talking about yourself again Dribble.

How about demonstrating your limited understanding of condensing boilers by answering the question I posed.

You really only have 2 choices:

Answer the question wrongly and show how clueless you really are

and

Don't answer the question at all and show how clueless you really are.

Oh and do hurry up. I want the latest incarnation of John Burns Curtis to join all his predecessors from Adam onwards in my killfile and wait only for the answer to my question.

[Dave Plowman (News)]

Given the large gap in your posting history it obviously didn't work for you. Demand a refund - or the medication adjusted.

And don't forget the aftercare.

[Doctor Drivel]

Please eff off you are a total plantpot.

[Doctor Drivel]

You are a plantpot.

[Roger]

The message from "Doctor Drivel" contains these words:

Just answer the question.

That is not the return temperature required to recover all the latent heat in the flue gases.

Yet more evidence that Dribble just doesn't have a clue about anything even remotely technical.

[Roger]

The message from Roger contains these words:

I have revisited this reply for 2 reasons.

Firstly because I managed to get the flue length wrong - it is 4 feet, not 6 feet.

Secondly it hasn't been pluming recently at all so the plume I have seen frequently in the past must have been confined to cold weather.

[Kostas Kavoussanakis]

Understood.

I presume that these are two additions to a boiler system. The former (assuming the *integrated* weather compensator) I guess is more straightforward; it's an external thermometer, linked to the boiler. Are there limitations about the location of this (e.g. "North-facing so as to be unaffected by direct sunlight and no more that 2m of cable") that may require that the boiler be moved?

The other seems perilously close to a room thermostat. Is this a case of replacing the control thermostat, or is it an addition to it?

And how do these increase the cost of installation/decrease choice of installers? I have noted your previous recommendations for Broag; are these also available for Worcester-Bosch and other popular brands?

Yes, I have seen this myself; these grants worked well for my family.

Thanks for the answers so far!

Kostas

[Dave Plowman (News)]

A thermostat simply switches at the set temperature. For this use you need a sensor which monitors the actual temperature in the room and sends it to the microprocessor. The sensor has no controls on it - you set the temp required via the boiler control panel. Which might help prevent people fiddling as some do with a thermostat.

[Andrew Gabriel]

The plume is CONDENSED water vapour, and it can still have done that inside the boiler.

Different designs of boiler catch different amounts for the condensate drain. There is at least one which deliberately sends all the condensate out of the flue so it doesn't need a drain.

You should see that appear only after the flue gas mixes with outside air. With a condensing boiler, you will see the plume coming right out of the flue pipe, even before it gets a chance to mix with outside air (assuming it is operating in condensing mode). The other key difference is that the flue gas is going to be around 55C with a condensing boiler, verses somewhere around 150C or higher with a conventional one.

[dennis]

Not really.. it has to condense on the heat exchanger. If it condenses in the air stream the latent heat will just go out the flu.

By pumping it out of a spray head, that's different.