Question re: continuous hot water heater occassional fault

[dedja]

I've got a Rinnai Infinity 24 gas continuous hot water heater that's great when it works, but occassionally we get the water going cold every couple of mins or so. This will happen maybe 10-20% of the time and all other times the unit is faultless.

It's been happening on and off for ages and not enough to worry about a callout fee to look at.

Initially I thought maybe it's the heat exchanger but that can't be right because it works most of the time.

The only other things I could possibly put it down to is either a randomly faulty controller or the regulated water pressure ... but I'm certainly no expert when it comes to these beasts.

Any plumbers out there with any suggestions?

[Dirko]

Does it happen in different showers ?

Ours happens in one but not the other

[A Mum]

Definitely not a plumber !!

But this did start happening to us, and then bang, the water tank in the hot water service gave way !
Don't know if it was a coincidence or not, but that's what happened.

We noticed the cold water thing that you're describing happening,
And then it completely packed up about 6 weeks later

[dedja]

Happens to both showers and has been happening for years ... the whole house is on the one unit.

... and no tank since it's an instantaneous or continuous unit.

[A Mum]

Ours was a continuous or Instantaneous unit too (Or so I thought)

Never ran out of hot water, no matter how many kids, how many showers etc were happening,
Until about 6 weeks before it packed up.

I thought it was a tank in there, but maybe I'm wrong, but there was water pouring out everywhere!!

Ah well, whatever, at least if yours have been doing this for years, you're probably safe Dedja!

[redden whites]

Pretty sure your gas regulator on the HWS is dying. A cheap repair I would imagine by any plumber/gas fitter in the yellow pages.

[StrayDog]

Not an expert in this field either dedja, but I'll try to help.

Is it possible that the problem has coincided with the installation of water saver shower heads?

Reason I ask is that I had, for memory, an almost identical problem several years ago with an older - though still healthy - instantaneous system after changing to a low-flow head.

I am aware that these types of systems often need a minimum flow for the burners to kick in, though can't speak with any authority on your Rinnai.

[JAS]

This is the result if you throw "Rinnai Infinity 24 troubleshooting" into Yahoo...

http://www.fixya.com/support/rinnai/water_heaters

Looks like it's free to 'ask an expert' so you might find something on there...can't hurt to try.

Regards
JAS

[dedja]

Pretty sure your gas regulator on the HWS is dying. A cheap repair I would imagine by any plumber/gas fitter in the yellow pages.

Good suggestion ... could be.

[dedja]

Not an expert in this field either dedja, but I'll try to help.

Per chance, has the problem coincided with the installation of water saver shower heads?

Reason I ask is that I had, for memory, an almost identical problem several years ago with an older - though still healthy - instantaneous system after changing to a low-flow head.

Can't speak with any authority on your Rinnai, though I am aware that these types of systems often need a minimum flow for the burners to kick in.

No sorry, we love our showers so no water saver shower heads ... even more shameful when you consider I used to work at SA Water.

As per Redden White's post, your 2nd part could be on the money.

[dedja]

This is the result if you throw "Rinnai Infinity 24 troubleshooting" into Yahoo...

http://www.fixya.com/support/rinnai/water_heaters

Looks like it's free to 'ask an expert' so you might find something on there...can't hurt to try.

Regards
JAS

Thanks JAS ... I did notice that site.

Anyway, looks like Mr Tightarse might have to call in the pros ...