Non condensing boiler condensing?

Hello,

My Granny has a Vaillant turboMAX+ combi boiler, I am posting because I am little worried that the boiler may be condensing when it's not supoosed to.

The system has very large radiators all with TRV's on them (No room stat) a flow temperature of only 55 degrees is required to warm the house on freezing cold days.

I am worried that with such low flow temps the boiler will be condensing which may corrode the heat exchanger.

Is it a thing to worry about?

Reply to
dawoodseed
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If it doesnt condense you wont have a high efficency boiler, 55 is good, above 59 and efficency of the boiler will drop alot. What is your opinion on when it should condense, it should always condense. You are lucky you dont have small radiators and need 82 when its real cold out, but where I am it goes to -30.

Reply to
ransley

Shouldn't be: these boilers are deliberately designed with much less efficient heat exchangers than condensing boilers so that they don't condense under such conditions.

Reply to
YAPH

They can do if the rads are too large and the boiler stat is set too low. Keep it set to 75C minimum.

Reply to
Doctor Drivel

Thanks for that, the problem is there is no room stat, the proposal is to fit a room stat and run the boiler at 82 degrees 24/7, my Granny likes the heating on all day and we will probably set it at around 18 degrees at night(not the flow temperature).

Does this seem like a sensible approach?

Reply to
dawoodseed

55 degC or less RETURN temperature will cause condensation on any boiler. In a non condensing boiler it will cause corrosion of the heat exchanger.

Yes, about all you can do really.

Granny would be better off with a modulating condensing boiler; the flow temperature could be turned down as low as possible whilst still maintaining the inside temperature. The gas savings would probably pay for it within 2 -3 years.

Reply to
Onetap

Yes, a condensing boiler would do very well on this system only requiring a maximum flow temperature of 55 degrees. We do not really plan to change it just yet; we have just moved in and the boiler works perfectly.

Reply to
dawoodseed

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