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bewsh

Plumbers Arms member
Plumber
Gas Engineer
Jan 15, 2013
608
106
43
Pontypridd, Wales
My brothers just moved in to his house which has been unoccupied for around 2 years.

Ferroli Optimax He Plus 31C at the property, so he asked if I could go and check it out as it hasn't been used for so long.

Emissions were miles out and it was making all sorts of noises, so set them up and all was running well in test mode. Checked the dhw, and that's working fine as well. But when I turned just the C/H on, it wouldn't go above 33 degrees, even though the temperature was set to 90 degrees.

I checked the return thermistor thinking that it could be faulty and telling the boiler it's up to temperature, I was getting 8.2kohms and checked the temperature of the pipe, which was 30 degrees.

Diverter not passing, pump running fine. Checked working pressure and gas rate at max test mode, all ok.

When I first put the heating on, it ramps up as it should for about 5 seconds, and then cuts down to minimum and stays like that.

There is a 4 wire temperature sensor by the primary heat exchanger, which I guess doubles as an overheat stat as well, but wasn't sure which connections to test between, but assumed that it's ok as the hot water was heating up fine.

Any ideas or suggestions would be greatly appreciated.

And if I put it in to max test mode, the heating all works fine and all radiators are nice and hot as you'd expect, rechecked the return thermistor, which was about 1.5kohm at max temperature.
 
I changed a pcb on a Ferrell once or maybe an ariston, but It had some dip switches on the pcb, one of them was to set heating max temp to something like 40 or 88... Has your boiler been set up like this by mistake?

I think the setting is for safety maybe so no one scalded by the rads or low temp? It's a long shot but worth checking...
 
There is a installer menu on that junk pile for configuring max temps, fan speed etc. but info is not in standard MI's for adjustments.
Think you will need call Ferroli for this one if nothing obvious.
 
I spoke to a guy who is a senior engineer for Ferroli, he said to check P11 in the installer menu, which is the c/h output, it was set at 1%. Adjusted that and it worked a treat. No idea why it was down at 1% mind!
 
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I spoke to a guy who is a senior engineer for Ferroli, he said to check P11 in the installer menu, which is the c/h output, it was set at 1%. Adjusted that and it worked a treat. No idea why it was down at 1% mind!

last plumber didnt get paid by landlord/owner?
 
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