Hi, any help on this appreciated.
My Sime Friendly Format 80E is playing up. When the heating has been burning for a while (1 hour or so but getting shorter) the boiler stops burning but the fan keeps running. Any requests for hot water result in a click (not the ignition) and then no hot water - it's like the bolier thinks its already running and doesn't try to re-ignite.
I had a heating engineer look at it and he diagnosed the flue pressure switch. After he replaced the pressure switch it worked fine for about a week but now the same problems back.
Does this sound like the pressure switch? Is it likely that the new part has failed so quickly or should I be looking for a different cause? ANY hints on diagnosis and repair appreciated.
Thanks in advance.

AlanK, March 2005

Hello,

About faulty controller SIT 503 EFD I wrote in my blog:
http://blog.belin.sk/index.php?PgId=9&Lang=En

It is better to replace only faultily relay instead of whole controller. Some of replacement relays I still have.

Filip, March 2010

hi i dont think its air pressure its more like ignition control pcb the one in blue box on the gas valve .you can buy these for £62.65 heatingsparesdistributors.caerphilly s wales.tel 02920 883399 (sime part No 6210203)

stephen, December 2008

Ohhh boy - you are the man Bob. Same problem, found a dry joint under one of the relays on the PCB in the blue box. Quick solder and hey presto it works.

Russ, April 2008

Bob Roberts, I'd just like to say "thankyou" for the advice you gave about the sime 80e. Our boiler was playing up too, just like yours and we checked the pcb, found some cracks and soldered them. Now the boiler works fine, just like before. Keep smiling, Bob.

Shubido, December 2007

Hi, I have a sime 80e and had the same problem, you are right to check out the pressure switch, this is done by testing the 240 volt supply on the control box pcb teminals 5,6,7, with your meter -lead on terminal 1 [N],but if you have proved the pressure switch is operating then the problem is definitly on the pcb,to sort this out you have two ways 1 buy a new control pcb at £72.00 minimum inc vat or 2 [ and this is what i have done], remove the pcb, the one fitted to the gas valve, and with an eye glass ie 10x magnification look at every soldered joint and you will find the joints to do with the relays that open the gas valves are cracked around the pyramid of
solder [a dry joint] check all joints I found about 12 very fine cracks,after resolering and fitting the pcb back, the boiler is now as new,by the way it has taken me 2 years to sort this out but was told every time to replace this pcb ,i mend boiler so i was not prepared to buy a new pcb knowing once i proved
it was the pcb i could repair it.if you need any more details then email me on r.roberts97@ntlworld.com take care ie be safe when working on gas or elect let me know how you have
gone on [its not hard to do this job if you can use a soldering iron] i will give you all the help i can .keep smiling bob roberts.

bob roberts, February 2006

Just an update,
Checked the tubes from the pressure switch and they were fine. Traced the problem to the ignition (controller) PCB - opened the blue box up and looked at the board - some of the soldering looked very scorched on the back and the blue box was discoloured in one corner.
Replaced the controller PCB - SIT part 503-EFD from theboilershop. Now working fine at last!
Cheers for your help Dom.
Alan.

AlanK, April 2005

Thanks Dom, I'll take a look.
The problem has been a bit better over the last week or so - I guess the warmer weather has meant the boiler hasn't been running so much and doesn't get so hot.

AlanK, March 2005

check small neoprene tubes that run between pressure switch and fan assembley these can be split or brittle (causing a problem only when hot)

Dom., March 2005

Forgot to mention, if I turn the hot water tap off and switch the heating to off then back on it seems to reset (most times) and is ok for a bit.

AlanK, March 2005