High return temperature on condensing boiler CH

Hi,

My boiler shows the return temperature of the CH on its display. Earlier today it was showing 75(C) which seems very hot. As it is a condensing boiler won't this mean it is operating outside its condensing mode?

What is a good solution for this? I don't think the pump is adjustable.

Reply to
Mark
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Does if have a flow temperature adjustment? Was the house warm? Have you got Thermostatic radiator valves? What make and model is the boiler? How many rads?

Reply to
John Rumm

Steam starts to condense at

Reply to
dennis

Yes. It's set to "E", if that's any help.

I would say it was nearly warm.

Yes (except in room with thermostat).

W-B Hiflow 440

13.
Reply to
Mark

I had heard that the flue gasses had to be below 55C to get the full benefit of the condensing mode.

I read the following on several web sites: "It is only possible for a condensing boiler to work to these very high efficiencies if the flow and return pipework is also kept below

55°C."
Reply to
Mark

You can treat that with a pinch of salt. Most of the waste heat saved is the latent heat of vapourisation. If you condense most of the steam you get nearly all the heat back. Cooling the flu gases down to 55-60C will only get you a very small amount of energy back. You could say that the return temp should be kept to 40c as then it is even more efficient. However it comes at a cost.. bigger radiators and making (and running) them wastes energy.

Reply to
dennis

More info. What make model of boiler for starters and any info you have on it.

Reply to
Doctor Drivel

This totally irrelevant too.

Reply to
Doctor Drivel

58C is the theoretical temperature in which flue gasses start to condense. In doing so they give off latent heat. The return water temperature needs to be about 54-55C to make the flue gasses condense.

The energy clawed back is about 12% to the best non-condensing boiler.

Reply to
Doctor Drivel

In article , Mark writes

It sounds as if your system has not been balanced, many (lazy) installers say that this is not required on systems with TRVs which is not true.

Follow the balancing procedure in the DIY faq at:

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Reply to
fred

readings. I bought an IR thermometer for this purpose. I can get stable temperature readings off everything but the ******* CH pipes. If I pointed it at them the reading was all over the place.

Reply to
Mark

Put some black PVC tape round the pipe and measure on that.

Reply to
Dave Plowman (News)

of one of my rads. Will this cause an issue where balancing is concerned?

Thanks,

Jon

Reply to
Jon

at:

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Not really. Some TRVs used to not like being on the return, but most are bidirectional these days. Makes no difference to balancing though.

Reply to
John Rumm

Thanks John.

Reply to
Jon

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