Valiant EcoMax hotwater going off and on frequently

Apr 25, 2009 7 Replies

Hi,



Can anyone advise me on what could be causing my Valiant EcoMax to fluctuate on the hot water.? I noticed it first a few days ago, when having a shower. Every 10 to 15 seconds the water went cold, then hot. The boiler seems to fire up and then go off when I listen to it. I ignored it for a few days but today, it stopped altogether, I switched it off and on and it fired up but still get the intermittent hot water. It may do the same on the hot water but we haven=92t had that on recently.


Can anyone advise me on what could be causing my Valiant EcoMax to fluctuate on the hot water.? I noticed it first a few days ago, when having a shower. Every 10 to 15 seconds the water went cold, then hot. The boiler seems to fire up and then go off when I listen to it. I ignored it for a few days but today, it stopped altogether, I switched it off and on and it fired up but still get the intermittent hot water. It may do the same on the hot water but we haven?t had that on recently.

Vaillants are notorious for high Gas pressure requirements, it could be your gas pressure needs raising higher.

What temperature is the display showing when it's doing it?

If it rises goes high (over 65C) and then cuts out and starts again when it's cooled down a bit it is most likely the plate heat exchanger that is blocked.

The Valiant EcoMax we have in flat above our shop started doing that within about 12 months. Valliant engineer came and went and said he'd replaced the divertor valve.

It started doing exactly the same thing a few years later, but as we just use the flat for shop storage as there's no acces to it apart from through the shop no-one showers or baths so I've not bothered. CH works fine which gets hammered through the winter being on to heat the shop 12 hours a day, so heat exchanger cant be the problem I don't think, and as symptoms are same as before I would expect the problem to be the same.

HTH Pete

If the unit is newish and the symptoms have come on suddenly, I'd go for the diverter valve. If the unit is older or you have been running the water temp setting above about "1 O'clock" in a hard water area... Then go for chalk in the 2ndry heat exchanger.

Yes, it reaches about 72, not what we set the dial to. Funny thing is that today it worked fine. The water was consistent, but I won;t count on it staying the same. Thanks for the reply. I guess replacing the Heat Exchanger is expensive.

Don't think it would be the heat exchanger if worked fine then, I have my hot water set at 45C and I've never seen the temperature going over

60C when it's heating the water; most of the time it is at 50C-55C, when we have the DHW at 50C it is at 58C. Told by an engineer that it shouldn't go over 65C when hot water is set at 45C.

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