Ferroli Maxima 35C hot water stuck at 50C

[mparsons]

Hi,

I got a Ferroli Maxima 35C installed during the summer when our house was renovated. We've had a lot of problems with maintaining water pressure (old + new system joined together) which has now been fixed by an excellent plumber who found all the leaks (took 3 months and 3 plumbers).

During this process Ferroli were called in to check the boiler. Since the engineer came round the maximum temperature for hot water has been 50C - even if I set the front panel knob to 65C.

The central heating water temperature works fine up to the maximum 85C temperature.

I assume the engineer has changed an engineer setting using the "M" key but I can't find any documentation anywhere to help me undo this change. Does anyone know (a) if this setting exists and (b) how I reset it? It's taking ages to run a not particularly hot bath!

Many thanks,

Mark

 

[chrishutt]

Are you sure the boiler is capable of delivering HW at more than 50C in this cold weather? In other words, does the burner flame modulate down during HW delivery to avoid exceeding 50C?

 

[mparsons]

Hi,

Yes - it's been quite warm in Edinburgh recently (12C today). During the really cold weather in January (and prior to the engineer's visit) the boiler managed just fine. The flame icon goes down when 50C is reached on the panel.

Cheers,

Mark

 

[chrishutt]

So does the flame modulate down?

 

[mparsons]

Yes

 

[Agile]

There are several things that I dont understand about your situation.

Firstly, the installer last summer should have given a guaranty on the installation and there was no need to call three plumbers to find his leaks.

Secondly, I dont understand why you want the hot water at more than 50*C.

I am not familiar with the detail of your boiler but I am aware of a European directive that limits the maximum DHW temp to about 60*C maximum. This is to prevent scalding and most boilers I deal with do not deliver DHW over 55*C to comply with this requirement.

You could call the manufacturers helpline to obtain clarification on these points.

Tony

 

[chrishutt]

Assuming you've studied the manual and found nothing, I can only suggest calling Ferroli technical for advice.

 

[mparsons]

There are several things that I dont understand about your situation.

Firstly, the installer last summer should have given a guaranty on the installation and there was no need to call three plumbers to find his leaks.

Secondly, I dont understand why you want the hot water at more than 50*C.

I am not familiar with the detail of your boiler but I am aware of a European directive that limits the maximum DHW temp to about 60*C maximum. This is to prevent scalding and most boilers I deal with do not deliver DHW over 55*C to comply with this requirement.

You could call the manufacturers helpline to obtain clarification on these points.

Tony

The installer did give a guarantee - and in fact it was him who called in the second plumber. We also called Ferroli in at this point. When Ferroli and this second plumber failed to fix the pressure problem I gave up waiting for a solution and called in a third plumber who very concientiously found a series of tiny leaks.

As regards the temperature - at the moment I can put my hand into the flow when filling the bath without it being scalding. This is a large old house with a long run to the bath and the water needs to be hot when it starts its journey. We've insulated everywhere we can but there are inaccessible areas which we can't get to without damaging the stripped floors.

I think I'll just give Ferroli a call and ask their advice. I have to say they've been very helpful so far.

Thanks,

Mark

 

[mparsons]

Assuming you've studied the manual and found nothing, I can only suggest calling Ferroli technical for advice.

Hi,

The manual doesn't even say what the 3 "engineer" buttons are for. There's an "M" button and a "+" and "-".

I'll take your advice and call Ferroli. I was trying to avoid having to stay in again waiting for them to visit.

If anyone does know how to make this adjustment I'm still very interested.

Many thanks,

Mark

 

[Agile]

Whilst you have a large house you should not lose too much temperature on the way to the hot taps.

A common fault is that old 22 mm tube and even lead pipe is left in use. All pipe from a combi DHW output should be in insulated 15 mm copper tube. That should not lose more that about 3*C in transit.

If you can keep your hand in the water then its not going to be much more than 42*C. Better to make any measurement accurately with a digital thermometer. Readings on a boiler are not necessarily the actual DHW exit temperature.

Another fault is cross flow from a thermostatic mixer or joystick tap without non return valves fitted. Turn off the cold water input to the boiler and make sure nothing comes out of the hot taps.

Tony

 

[mparsons]

Whilst you have a large house you should not lose too much temperature on the way to the hot taps.

A common fault is that old 22 mm tube and even lead pipe is left in use. All pipe from a combi DHW output should be in insulated 15 mm copper tube. That should not lose more that about 3*C in transit.

If you can keep your hand in the water then its not going to be much more than 42*C. Better to make any measurement accurately with a digital thermometer. Readings on a boiler are not necessarily the actual DHW exit temperature.

Another fault is cross flow from a thermostatic mixer or joystick tap without non return valves fitted. Turn off the cold water input to the boiler and make sure nothing comes out of the hot taps.

Tony

The kitchen tap which is right beside the new boiler is too hot to put my hand in but the bathroom isn't so it's definitely losing a lot of heat on the way. I'll check for cross flow tomorrow.

Many thanks,

Mark

 

[mparsons]

Hi again,

Ferroli finally fixed my problem last week by replacing the heat exchanger. Basically, we'd also been suffering pressure loss from the system. Ferroli were convinced that this was a plumbing problem. However, I treated the system with Fernox (sp?) at their suggestion and a few days later the heat exchanger started repeatedly overheating.

Replacing the heat exchanger has resulted in:

- Loads of hot water for bath and shower (so hot I can't put my hand in it)
- No loss of pressure for the past week

My advice would be to stand your ground with Ferroli who will take you seriously if you follow their advice (pressure test system to 5 bar, then Fernox in my case).

Cheers,

Mark