THE CONCISE VERSION FIRST
Why would a ProTherm 40-50 CI boiler only come on when the thermostat knob on the front is at 0 and go off when I turn it round to anything higher? With it set at 0, it never shuts down and consequently overheats.
The knob used to be set at MAX permanently, but setting it to that after igniting at 0 just makes it go off. Only if I've managed to keep it on for 30 mins or so set at 0, can I then move the dial all the way round to point at MAX without it going off. Of course, when I turn off the heating with my main control and later want it back again, it won't come on unless I turn it to 0.
I suspect whatever controls my ProTherm boiler coming on and going off is at fault. Is that the PCB, the thermostat or the thermocouple or something else?
MY ORIGINAL DETAILED POST
Some background:
I became a dad on January 1st and have had heating on in my house continously for the last 7 weeks to keep my baby warm enough. (There is no room thermostat, but all radiators have TRVs, so I set them to low.) I set the water to come on for a couple of hours in morning and at night.
Now the problem:
I woke Sunday morning to find the house was very cold. I went to the boiler (ProTherm, conventional - not combi) and saw that it was not lit. I pulled the front off and saw some instructions, describing how to operate the knob on the front (the boiler thermostat, I assume). I also saw an overheat cutoff button, so I pressed that in first, but nothing happened. The current setting on the knob was at MAX, so I tried lowering it to 0 to perhaps reset the system. (I was guessing.) At this point, the boiler came on. As soon as I turned it towards MIN on the dial, the boiler went off. I thought this was very weird, as it had been functioning correctly at MAX in the past and would now only come on at 0. Still, my boiler was working, so I went back downstairs to enjoy the heat that would soon be coming out of my radiators.
About an hour later, I got loud clanking and gurgling/sputtering from above the pump (which was making a kind of whirring noise as well) and the boiler went off automatically. It turns out that it had overheated. I decided to leave it a while and then I returned later to press in the red button on the front of the boiler (which had now flicked out) and it came on again. Can't remember how long passed, but the clanging happened again so I turned the heating off at the timer-controller.
At this point, I wasn't sure what was wrong. I wondered whether we were asking too much of the sytem, so I turned all the radiators TRVs off and tried again about an hour later. At this point, the thing overheated much quicker.(In hindsight, I can see that it was insane to turn off all the TRVs as that will obviously lead to overheating faster cos there's less room for the hot water to spread out in the system.) I also tried with all the radiators on full, but I guess (on reflection) everything was still too hot.
I started fresh on Monday morning and got about one hour's operation before the clanking began - I turned it off in the kitchen before the boiler actually overheated this time. At this point, I wasn't sure what was wrong, so I called up Reactfast, who charge £64+VAT an hour. I explained my problems when the guy arrived and he said the pump needed changing (there was at least a missing venting nozzle, which I noticed had dripped one drop of water), and he was also confused by the boiler thermostat.
Since I was paying him by the hour and the system had cooled down, naturally no problems arose while he was there! He did turn the pump down from 3 to 2 and ran a few diagnostics with me. He got me to open up all the rad TRVs and turn on the hot water. I made sure I got lots of useful info out of the guy for my money, and made him a cup of tea to keep him the full hour I had paid for, in case something went wrong in that hour! Nothing did of course .. until I tried again a couple of hours later, well after he had gone.
The guy recommended getting a combi boiler, which I am considering, as he thinks the pump needs replacing and possibly the boiler thermostat, all of which are wasted money if I elect to get a combi later.
Thinking about it all this morning on the way to work, I think it is all down to the faulty thermostat on the boiler: it broke during the night and all went off for Sunday morning. I then got things back on at 0, which I believe does not automatically turn off based on temperature of water, which led to the overheating. All the clanking and pump noise is due to running water that is too hot through the system.
THANKS FOR READING THIS FAR! NOW HERE IS MY QUESTION:
Is it safe to assume that it is just the boiler thermostat at fault or a PCB and maybe there is nothing wrong with the pump after all? The boiler is a ProTherm, which the previous owner of the house tells me is only 4 years old. Until this morning, I was going to book the installation of a combi, but now I am thinking I just need to get the boiler stat fixed.
If anyone can shed some light on my situation that would be great!
Why would a ProTherm 40-50 CI boiler only come on when the thermostat knob on the front is at 0 and go off when I turn it round to anything higher? With it set at 0, it never shuts down and consequently overheats.
The knob used to be set at MAX permanently, but setting it to that after igniting at 0 just makes it go off. Only if I've managed to keep it on for 30 mins or so set at 0, can I then move the dial all the way round to point at MAX without it going off. Of course, when I turn off the heating with my main control and later want it back again, it won't come on unless I turn it to 0.
I suspect whatever controls my ProTherm boiler coming on and going off is at fault. Is that the PCB, the thermostat or the thermocouple or something else?
MY ORIGINAL DETAILED POST
Some background:
I became a dad on January 1st and have had heating on in my house continously for the last 7 weeks to keep my baby warm enough. (There is no room thermostat, but all radiators have TRVs, so I set them to low.) I set the water to come on for a couple of hours in morning and at night.
Now the problem:
I woke Sunday morning to find the house was very cold. I went to the boiler (ProTherm, conventional - not combi) and saw that it was not lit. I pulled the front off and saw some instructions, describing how to operate the knob on the front (the boiler thermostat, I assume). I also saw an overheat cutoff button, so I pressed that in first, but nothing happened. The current setting on the knob was at MAX, so I tried lowering it to 0 to perhaps reset the system. (I was guessing.) At this point, the boiler came on. As soon as I turned it towards MIN on the dial, the boiler went off. I thought this was very weird, as it had been functioning correctly at MAX in the past and would now only come on at 0. Still, my boiler was working, so I went back downstairs to enjoy the heat that would soon be coming out of my radiators.
About an hour later, I got loud clanking and gurgling/sputtering from above the pump (which was making a kind of whirring noise as well) and the boiler went off automatically. It turns out that it had overheated. I decided to leave it a while and then I returned later to press in the red button on the front of the boiler (which had now flicked out) and it came on again. Can't remember how long passed, but the clanging happened again so I turned the heating off at the timer-controller.
At this point, I wasn't sure what was wrong. I wondered whether we were asking too much of the sytem, so I turned all the radiators TRVs off and tried again about an hour later. At this point, the thing overheated much quicker.(In hindsight, I can see that it was insane to turn off all the TRVs as that will obviously lead to overheating faster cos there's less room for the hot water to spread out in the system.) I also tried with all the radiators on full, but I guess (on reflection) everything was still too hot.
I started fresh on Monday morning and got about one hour's operation before the clanking began - I turned it off in the kitchen before the boiler actually overheated this time. At this point, I wasn't sure what was wrong, so I called up Reactfast, who charge £64+VAT an hour. I explained my problems when the guy arrived and he said the pump needed changing (there was at least a missing venting nozzle, which I noticed had dripped one drop of water), and he was also confused by the boiler thermostat.
Since I was paying him by the hour and the system had cooled down, naturally no problems arose while he was there! He did turn the pump down from 3 to 2 and ran a few diagnostics with me. He got me to open up all the rad TRVs and turn on the hot water. I made sure I got lots of useful info out of the guy for my money, and made him a cup of tea to keep him the full hour I had paid for, in case something went wrong in that hour! Nothing did of course .. until I tried again a couple of hours later, well after he had gone.
The guy recommended getting a combi boiler, which I am considering, as he thinks the pump needs replacing and possibly the boiler thermostat, all of which are wasted money if I elect to get a combi later.
Thinking about it all this morning on the way to work, I think it is all down to the faulty thermostat on the boiler: it broke during the night and all went off for Sunday morning. I then got things back on at 0, which I believe does not automatically turn off based on temperature of water, which led to the overheating. All the clanking and pump noise is due to running water that is too hot through the system.
THANKS FOR READING THIS FAR! NOW HERE IS MY QUESTION:
Is it safe to assume that it is just the boiler thermostat at fault or a PCB and maybe there is nothing wrong with the pump after all? The boiler is a ProTherm, which the previous owner of the house tells me is only 4 years old. Until this morning, I was going to book the installation of a combi, but now I am thinking I just need to get the boiler stat fixed.
If anyone can shed some light on my situation that would be great!
