Ariston Next Evo X SFT multipoint water heater. Temperature issues.

[DaveDCLXVI]

Hi all This is my first post here.

My Dad recently had an Ariston Next Evo X SFT 16L multipoint water heater installed to replace the previous one that was leaking.

What concerns me is that it basically takes about one and a half minutes for the water to reach even a a basic useful temperature. By that I mean warm (not hot) enough to have a shower or wash dishes.

The water does not even get what I would describe as hot. It rarely gets so hot that you cannot hold your hand under the tap even though the temperature is set to 48C.

I know one and a half minutes is not a long time in most circumstances but when you're just standing there waiting for a tap to heat up, if feels like an eternity.

Is this normal for this unit? On the previous heater, I would estimate it only took about 20-25 seconds to get really hot.

My Dad is taking the view that that's just the way the heater performs but I think he should be getting onto the plumbers that put it in to check that it's installed properly.

I would greatly appreciate the forums thoughts on this.

Cheers

David

 

[Deleted member 120897]

If it was a recent install, perhaps Ariston for a warranty call?

 

[DaveDCLXVI]

Thanks for replying Chris.

The heater was put in Mid December. At this stage I'd rather the plumbers who did the install had a look at it. I'm really just looking for confirmation that the heater is not working as it should so I can approach the plumbers with some confidence that I'm not wasting their time.

 

[John.g]

You could check that its power input is 30kw by monitoring the meter, also that its not in eco mode. Assuming mains at 7C then 30kw will give a max flow of 10.5 LPM at 48C, if you run it at 16LPM it will only give a temperature of 33.9C.

 

[DaveDCLXVI]

Hi John thanks for your reply.

The meter only gives a figure in meters squared. Apparently, I'll need the calorific gas value from my Dad's bill to make the conversion and that's not possible as he is away.

While any input is greatly appreciated, at the end of the day, all I'm really looking for from the forum is a 'yes' or 'no' to the question: is this the normal expected performance for this particular heater (assuming the gas input is is at optimal level)?

Cheers
David

 

[John.g]

Can't really tell you how long it should take to get HW from your tap, depends on pipe run and diameter but would think that ~ 30 secs would be normal but I can tell you that if you take a snapshot of the meter reading at the start and end of a 3 min run that you should see a gas consumption of ~ 0.16m3 if you open a number of HW taps to give a combined flow of 10.5LPM, maybe try that for a start?

For a quick test just open all hot taps fully and see if you get that 0.16m3 in 3 minutes.

 

[DaveDCLXVI]

Cheers John that's good advice. I'll give that go.

 

[DaveDCLXVI]

OK I just tried your suggestion John. The gas consumption in 3 minutes (all hot taps full on) was 0.142m3.

Cheers
David

 

[John.g]

Thanks David,
0.142m3 in 3 mins = 2.84m3/hr, assuming natgas CV of 11kw/m3 = fuel input of 31.24kw = heater output of 28kw at 90% efficiency so proof enough that the heater is giving ~ its full output?

Don't know how this heater controls its output, if it controls the temperature like a modulating gas boiler then you should be able to reduce the HW flow to around 2.0LPM at 48C (from cold at 7C) assuming minimum output at 6kw. If it performs like this then heater probably OK. So maybe try a few different lowish HW flowrates and see how it performs.

 

[DaveDCLXVI]

Hi John.

Well that's that cleared up. We'll try giving the water rate an adjustment and see if things improve.

That's been a really great help and I am very grateful to you John

Also, thanks again to Chris for taking the time to reply.

David

 

[Pauljenkins]

Hi did you ever solve this? I have exactly same issue. Installed a few days ago into a static caravan with LPG. Water never gets really hot in fact even at 65 degrees I think it performs worse. This is a brand new unit just wondering if you solved it before I call Ariston .thanks Paul

 

[ShaunCorbs]

What’s the flow rate out of the hot tap