CH stuck on and not responding to timer

[shivering]

Hi All,

Hope someone has a clue..

Boiler: Ferroli Optimax HE31C
Thermostat : Drayton Digistat SCR with wireless RF1 unit
Timer/clock : Servowarm model LP111

The problem I have is that an engineer came out and moved said boiler from bathroom (!!) to the garage. In moving the boiler he has also moved the thermo from near the boiler and the timer from the kitchen so it's all sitting in the garage. The wireless unit is in the understands cupboard.

Since the move the boiler does not want to switch the heating off. It doesn't respond to the timer at all and I cannot switch the heating off through the boiler. The hot water works on request and I have had to turn the CH right down.

Fearing he may have wired it incorrectly he came back out and removed the timer from the equation. The permanent live is obviously still running to the boiler but now no timer connected.

He had a closer look at the board and there is a resistor that seems to have scorched on the card (it's completely black and has left residue on the plastic cover.

The boiler however has presented no fault codes and will allow me to change temperatures for both water and heating with no issues at all.

Any ideas?

 

[shivering]

Bump...

 

[ChrisOxford]

As no-one else has posted, how about a few quesitons for you to get the ball rolling...

(1) Did everything definitely work OK before the boiler was moved?

(2) When the engineer returned, what was his conclusion? No idea at all?

(3) Which board are we talking about? One in the boiler? Either way, could you post a pic of the board showing the scorched resistor.

(4) Is it impossible to switch the CH off using the thermostat (i.e. by turning it down to, say, 10 degC) too?

(5) Have you tried disconnecting the wires from terminals 5 & 6 to see if the CH shuts down?

Manual for the boiler here, BTW: http://www.whitesplumbing.co.uk/pdfs/ferroli_combination_boiler.pdf

N.B. I note the warning on the very top of page 18 which states:

CAUTION: THE ROOM THERMOSTAT MUST HAVE VOLTAGE FREE CONTACTS. CONNECTING 230 V. TO THE TERMINALS OF THE TIME CLOCK AND ROOM THERMOSTAT WILL IRREPARABLY DAMAGE THE PCB

I hope your engineer did too. Otherwise, he might possibly owe you a new PCB and have some re-wiring to do. Your talk of "permanent live" implies there was a switched live... which there shouldn't have been in this instance.

 

[shivering]

1) Everything worked fine

2) His conclusion was that the board was the issue. He states that the wiring is fine

3) Yep I'm talking about the board in the boiler. He took the cover off and found the scorched resistor. When looking at the card it it's flat laying down position it is on the top right - will try and get a picture soon.

4) The boiler pays no attention to the thermostat whatsoever.

5) Disconnecting the Wires from 5 and 6 made no difference. The boiler continued to run - until I got home and found the fault F37, low pressure/sensor problem and the boiler shut down.

I'm not sure about the thermostat contacts or the switched live but will ask him when I see him next.

Now the system is showing this fault code does this mean anything different?

 

[ChrisOxford]

Sorry, I know nothing about your boiler or its fault codes, other than the quick glance I had at the manual last night.

I still have a nasty suspicion that the boiler's PCB has been fried by having AC mains inadvertantly shoved up part of it that runs at low, DC voltage, due to a wiring error when the boiler was re-installed.

Good luck, and please do let us know the outcome.

 

[shivering]

Sorry, I know nothing about your boiler or its fault codes, other than the quick glance I had at the manual last night.

I still have a nasty suspicion that the boiler's PCB has been fried by having AC mains inadvertantly shoved up part of it that runs at low, DC voltage, due to a wiring error when the boiler was re-installed.

Good luck, and please do let us know the outcome.

Ok, well Ferroli have been out and looked at the boiler and said that there is a wiring fault.

Oh the joy.

 

[ChrisOxford]

Ok, well Ferroli have been out and looked at the boiler and said that there is a wiring fault.

...and things are fine now that's been corrected?

Or is the PCB toast because of the above?

 

[shivering]

Ok, well Ferroli have been out and looked at the boiler and said that there is a wiring fault.

...and things are fine now that's been corrected?

Or is the PCB toast because of the above?

The wiring has been checked by the sparky and hes said it's fine. The PCB has been replaced and it's now coming up F37 - Low pressure/sensor fault. The pressure sensor works fine as the old PCB when plugged in allows the system
to work to at least give hot water but gives the constant heating. The new PCB won't get past the initial FH stage before locking out to F37.

Weird!

 

[shivering]

It was the PCB after all, all now fitted and correct. So much for the ferroli engineers very very poor diagnosis!