DIY Doctor UK DIY Forums

I HAVE AN IDEAL MEXICO 2 BOILER AND LAST WEEK IT STOPPED WORKING. THE PILOT LIGHT REMAINED ON.
I AM AN ELECTRICIAN AND TESTED TO MAKE SURE ROOMSTAT WORKING CORRECTLY AND HOT WATER AND CENTRAL HEATING SWITCHES WORKING CORRECTLY, ALL WERE.
I TESTED AT THE BOILER AND HAD 240 AT MAINS AND NOTHING AT GAS VALVE TERMINALS. I TEMPORARILY PUT A LINK ACROSS AND THE BOILER FIRED.
ONE OF THE PLUMBERS AT WORK GAVE ME A THERMOSTAT WHICH HAD A LONGER PROBE AND WASN'T THE EXACT SAME PROBE LENGTH AND IT DIDN'T WORK.
SO I ORDERED A NEW BOILER THERMOSTAT FROM THE NET. IT CAME AND I HAVE FITTED IT. THE BOILER FIRED AND WORKED FOR ABOUT TWO MINUTES AND THE THERMOSTAT TURNED ITSELF OFF THINKING IT HAD REACHED TEMPERATURE.
IT SEEMED TO BE WORKING CORRECTLY BUT THE THERMOSTAT SENSOR SEEMS TO BE SET TOO SENSITIVE AND TURNS OFF TOO SOON. I TOOK THE PROBE OUT OF THE BOILER AND SURE ENOUGH AS THE TEMPERATURE DROPPED THE BOILER FIRED. I PUT THE PROBE BACK IN AND THE BOILER TURNED ITSELF OFF STRAIGHT AWAY.

IS THERE ANY WAY TO ADJUST THE THERMOSTAT. CAN IT BE SET AT THE WRONG TEMPERATURE FROM THE MANUFACTURERS.
I'D APPRECIATE ANY HELP!!
REECE

It is a very hit and miss thing to try recalibrating a thermostat. I would change it.

Hi I think you should look at the pump, I suspect either a jammed/faulty pump or the pump is air locked, try removing the large screw on front , if air comes out while you are undoing the screw, refit when water comes out and try again. if not take screw all way out, watch out as water will come out, have the power off and a cloth to catch the water, then try turning the shaft, hope this helps :lol:

HI
I HAVE TRIED UNSCREWING THE PUMP BUT TO NO AVAIL........
ANY OTHER SUGGESTIONS?
I THINK I WILL HAVE TO GET SOMEONE IN..........
WITH THIS AGE OF BOILER DO YOU THINK IT MIGHT BE WORTH GETTING IN BRITISH GAS ON A FIXED PRICE TO FIX THE BOILER AND IF THE UNABLE TO FIX IT NO PAYMENT IS REQUIRED?
THANKS REECE

Hi, Yes that might be a good idea, but do not use them otherwise as too expensive, ask friends ect for a good corgi registered installer to change the boiler.

The most common cause of your problem is that the pump has stopped working.

You said originally that the boiler only fired up for a two minutes, I would have expected it to run for longer than that even if the pump was not working.
The Mexico, if I'm thinking of the right boiler, is a cast iron boiler and would normally run for quite a while from cold before the stat turned it off even if the pump was not working.

However, as I said earlier, the most common cause of this fault is the pump. When you fire up the boiler and the stat turns it off, is the boiler casting hot ?

If it is, try a new pump.

thank you i think i will have to do that..

I also have one of these boilers,we tend to leave the hot water on all day as we have many kids who like baths

I have a tank stat but find the water is getting heated to a very hot temp,could the tank stat be faulty because the boiler seems to be heating to the boiler stat(1 to 6) and not what I set it too on the tank stat,does this make sense

PS,this seems a good site,hello all :wink:

hi if you goto the parts centre which is part of the plumb centre you can pick up a thermocoupling for that boiler. If you change this the boiler should stay on longer as the thermocoupling will allow the gas valve to open. it seems that everything starts to work but the thermocoupling will shut off the gas if it does not get hot enough. then you have to wait 5 minutes and try again. so i would say that it is cheaper to try changing the thermocoupling first.