Upgrade to a Condensing boiler - yes or no?

Aside from my other post re. repairing existing boiler. I am tempted by the higher efficiencies of the condensing boilers but are there hidden problems in upgrading an existing installation. I do not need a combined boiler - I have HW cylinder and pump / valves. Concerns I have are -: Cleanliness of existing system - any prerequisites? Will existing rads be ok - presuming that water temp is lower???? TIA. Rob

Reply to
robf
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Thanks - very informative.

One point on the modulation - I have an external pump and valves .. should I go for a boiler with internal pump so the boiler can vary it as needed .. I presume that using the existing pump will not allow full control over the flow by the boiler other than on / off.

So many boiler options .. Ideal Icos is on the short list

Reply to
robf

Have it flushed out. Put in flushing agent before scrapping it. Flush with fresh water about three times.

Some modern modulating condensing boilers are designed for existing 80C temp installations. It modulates to suit. If it needs full 80C it gives it. Most of the time it will be on part load

If you buy a boiler which modulates the internal pump, then just remove the existing remote pump. Simple.

Reply to
IMM

I vote this goes in a condensing boilers FAQ.

Reply to
Ed Sirett

It has come up a few times, hasn't it.

Maybe if Phil is reading, he could pick this up.

Also, I think this is closely allied to your sealed system FAQ and it would be worth having that or a pointer to it as well.

.andy

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Reply to
Andy Hall

When yours is up, we can add xref links. The only thing I feel called to query in the above was...

This is not the province of condensing boilers per se. Firstly modern non-condensing boilers can and do modulate and there control systems exploit this. The difference is that by using forced premix burners (cf atmospheric burners), they can modulate over a deeper range.

Reply to
Ed Sirett

I bit of work required though.

Reply to
IMM

conventional

pre-mix burners are used in all boilers.

Reply to
IMM

Approximately pH4, and metal pipe can't be used.

Heat exchangers can also be cylindrical like the Econox/Spiranox burner/heat exchanger.

This does not necessarily mean that no cleaning is needed in the burner/heat exchanger chamber. The manufacturer's instructions should be followed.

With weather compensation it may well also start at part load.

That is irrelevant since this is a UK group.

That depends on what the manufacturer offers or specifies.

The objective was a simple and concise piece which covers most of the salient points without introducing irrelevancies. One or two of your points may be useful, once the spelling and grammar are corrected, but that is all. The intent was not to make this into a diatribe about peripheral issues.

.andy

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Reply to
Andy Hall

That was not implied. The heat exchanger does not require cleaning as stated.

As always.

That is merely another level of control and not necessarily directly aplicable to a condesning boiler. A good compensator will start on full heat until the building is up to temp. A boost function.

It gives a good indication of the way matters are moving.

This is great advantage and it was not mentioned at all.

Your so-called FAQable piece was sadly lacking. Now you know.

Like compensators?

Reply to
IMM

My point is that they are not particular to condensing boilers, although most are in condensing boilers. The Ideal Response has a pre-mix burners yet is not a condenser.

Reply to
IMM

Is there anything else that is sensible and relevant that you want to add? I've included some of your points (e.g. flexibility of flue systems and modes of operation) as well as Ed's.

.andy

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Reply to
Andy Hall

Show us the draft.

Reply to
IMM

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