I've been wondering about ways to control the return water temperature on my Worcester 24Ri boiler. The front panel control sets flow temperature leaving the return temperature to its own devices. Would installing a blending valve be worthwhile to keep the return temperature down to optimum condensing temperature be a good idea? The aim would be under normal demand conditions to keep the flow temperature as low as possible so condensing mode would be achieved most of the time with a typical 20 degree delta T across the rads, but when in the depths of an arctic blast, I could raise the flow temp setting and yet keep the boiler in condensing mode. Any thoughts? TIA Bob

In article , Bob Minchin writes I'm afraid it's a system design issue, the only way to get a greater drop is to increase the size of the heatsink, ie the radiators. However, it doesn't really matter how you get your 40-50degC return temp, if you set the flow to 50 and drop only 10 then you still get an uber efficient 40 degree return. Don't be tempted by to increase drop by throttling the rad flow though, systems should be balanced, not throttled.

How to maximise efficiency of a condensing boiler

May 31, 2013 21 Replies

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John Rumm 13 years ago

A tad industrial perhaps, but it would work...

Indeed.

What about the control pot? Is that connected in a similar way or is it hard wired to the PCB?

Even if it was, you could add eepots or similar in shunt and series arrangements to take control of it in a fairly easy to reverse mod.

(it has to be said it took quite a few hours of research to find a boiler that could do all these tricks out of the box (i.e. weather compensation, split temperature operation, multiple zones etc)

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Bob Minchin 13 years ago

I've got the current one all boxed ready for WB to collect so I can't look at the pot connections. It failed my visual inspection of the internals which included a missing clip to retain the gas valve outlet pipe and an internal flue joint that was all c*ck eyed with a suspected displaced seal. No way that boiler had a proper QA inspection.

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