This is a fantastic video - by far the best I’ve found that explains clearly what can cause boilers to keep going when one might expect them not to. The explanation of the wiring was useful too, though the advice to get a professional involved if it’s a wiring issue seems very sensible!
my combiboiler keeps pumping something out for 30sec every 8min. It isn't turning on like heating water as flame doesn't turn on. And preheat function should be switched off. As i selected off on the controller. Boiler guy came and said it was flow valve filled with limescale. He replaced it, and it now turns on for 3 seconds every 8min. Is that normal, Any idea why it keeps venting something for 3 seconds every 8min?
Do TRV control boiler, ive set thermosate to 15c boiler to 55c and trv all fully open. Yet boiler keeps heating and heating past thermostat 14c to 21c. I know the thermostate over reads and ive Offset that to (-3) setting seems to little control over boiler.
This video is amazing helped me understand the Vaillant controls so much. I tried some of your tips but didn't help unfortunately. Despite heating and water being 'off' the boiler heats up everytime it drops to 69deg up to 84+ then dumps the heat again dropping to 69 and repeats this all day , pls help!!!!
My heating was running flat out all night during the recent cold spell. It was due to an outdoors frost stat set at 0C, so I fitted another stat on the return pipe, in series with the outdoors stat. The boiler now only fires up when it’s less than 0C outside AND the return water is less than, say, 10C. Seems fine now.
Hi Mark. I have the problem where the circulation pump stays on after the HW has reached temperature which I think is due to the Honeywell zone valve holding a residual voltage. The tank stat works fine and if I dial it down to 20°C the valve actuates and the pump stops. Do you have a link to the capacitor that I need to install please. The Baxi boiler doesn’t ignite/burn but the LED is on and the circulation pump and zone valve both stay on/open. Plumber isn’t certain whether to replace valve or install a capacitor across the valve terminals rather than the boiler as you show in your video.
Why does our combi gas boiler make a humming noise with no heating or hot water demand. It can last all day and night even when its warm outside. It does not sound like the co2 fan which is louder, which normally over runs for a while? It works normal other than that. I have reduced the water inlet pressure but to no avail. Any other idea's? It only stops when the boiler power is off.
Hi Mark I have a Vailant combi in my caravan so if I turn the water off but leave the power and gas on for the duration of the 2 month shut down Jan to March will it protect my boiler ?
Try again hello mark I have a gloworm flex icon 18 my water heating when on the timer seems to be on all the time 24hrs as the boiler is sited in the cold garage could this be causing the boiler. to run constantly or is there something else wrong many thanks martin
My boiler produces warm heat to the radiators ( certain ones) i was told that the heat has to go somewhere. The boiler is not running when its slightly warm
Hello. My boiler pressure gets very high after turning heating on. Any idea what's wrong? Steps done so far Did radiator bleeding and lost pressure Represurised boiler to 1,5 Boiler start to go up 2,5 bar and above Did bleeding again to drop it down Didnt help it got back again quick Reset the boiler Didnt help also
Great video Mark. I have a strange issue that has occurred since I replaced my pump on a conventional boiler with an F&E tank. In the evening my boiler heats the water as expected but when the nest says it should be off it still fires up and heats the water until the tank stat says it’s satisfied. I have disabled the legionnaires setting on the Nest and it does not heat up at any another time. It’s a real head scratcher and I wonder if there is an old water heating program on the Nest platform that the app or thermostat is not picking up 😮
ah god i wish you were in Ireland! i have climote heating system, boiler fires up whenever it feels like it, even if thermostat set to zero! . already had a motorised valve replaced 6 months ago, and its back doing the same problem again, Just this time itermittently. Plumber said its a wiring issue. yet i cant get an electrician to come near it :( unfortunately, we dont have any "off" switch. best we can do is turn rads right down, and boiler turned down, while we wait for electrician ..... sigh!
This man is an absolute genius and has got to be the best heating and plumbing engineer in the business.
That last capacitor one was gold. Thanks very much
This is a fantastic video - by far the best I’ve found that explains clearly what can cause boilers to keep going when one might expect them not to. The explanation of the wiring was useful too, though the advice to get a professional involved if it’s a wiring issue seems very sensible!
Thanks you have made it clear to me why my system is doing the same thing 👍
Thankyou so much...i now know we have an issue with valves in the tank 😭...very informative video. 👏
my combiboiler keeps pumping something out for 30sec every 8min. It isn't turning on like heating water as flame doesn't turn on. And preheat function should be switched off. As i selected off on the controller.
Boiler guy came and said it was flow valve filled with limescale.
He replaced it, and it now turns on for 3 seconds every 8min.
Is that normal, Any idea why it keeps venting something for 3 seconds every 8min?
Do TRV control boiler, ive set thermosate to 15c boiler to 55c and trv all fully open. Yet boiler keeps heating and heating past thermostat 14c to 21c. I know the thermostate over reads and ive Offset that to (-3) setting seems to little control over boiler.
This video is amazing helped me understand the Vaillant controls so much. I tried some of your tips but didn't help unfortunately.
Despite heating and water being 'off' the boiler heats up everytime it drops to 69deg up to 84+ then dumps the heat again dropping to 69 and repeats this all day , pls help!!!!
Thank you so much!
Very good information Marc plane and simple for a none gas engineer!
I enjoyed watching!
My heating was running flat out all night during the recent cold spell. It was due to an outdoors frost stat set at 0C, so I fitted another stat on the return pipe, in series with the outdoors stat. The boiler now only fires up when it’s less than 0C outside AND the return water is less than, say, 10C. Seems fine now.
Hi Mark. I have the problem where the circulation pump stays on after the HW has reached temperature which I think is due to the Honeywell zone valve holding a residual voltage. The tank stat works fine and if I dial it down to 20°C the valve actuates and the pump stops. Do you have a link to the capacitor that I need to install please. The Baxi boiler doesn’t ignite/burn but the LED is on and the circulation pump and zone valve both stay on/open. Plumber isn’t certain whether to replace valve or install a capacitor across the valve terminals rather than the boiler as you show in your video.
Why does our combi gas boiler make a humming noise with no heating or hot water demand. It can last all day and night even when its warm outside. It does not sound like the co2 fan which is louder, which normally over runs for a while? It works normal other than that. I have reduced the water inlet pressure but to no avail. Any other idea's? It only stops when the boiler power is off.
I’ve got a potterton Prima boiler, it comes on when heating or hot water isn’t on.
Only when it cold not in summer.
Hi Mark I have a Vailant combi in my caravan so if I turn the water off but leave the power and gas on for the duration of the 2 month shut down Jan to March will it protect my boiler ?
Yes it should do it has built in frost protection.
Try again hello mark I have a gloworm flex icon 18 my water heating when on the timer seems to be on all the time 24hrs as the boiler is sited in the cold garage could this be causing the boiler. to run constantly or is there something else wrong many thanks martin
My boiler produces warm heat to the radiators ( certain ones) i was told that the heat has to go somewhere. The boiler is not running when its slightly warm
Excellent video
Hello. My boiler pressure gets very high after turning heating on. Any idea what's wrong?
Steps done so far
Did radiator bleeding and lost pressure
Represurised boiler to 1,5
Boiler start to go up 2,5 bar and above
Did bleeding again to drop it down
Didnt help it got back again quick
Reset the boiler
Didnt help also
Your expansion vessel needs to be positively charged.
My vailliant boiler was installed badly. He connected both high and low voltage so it was constantly calling for heat
Great video Mark.
I have a strange issue that has occurred since I replaced my pump on a conventional boiler with an F&E tank. In the evening my boiler heats the water as expected but when the nest says it should be off it still fires up and heats the water until the tank stat says it’s satisfied. I have disabled the legionnaires setting on the Nest and it does not heat up at any another time. It’s a real head scratcher and I wonder if there is an old water heating program on the Nest platform that the app or thermostat is not picking up 😮
First thing I would do is find out what's not turning off or what staying on. A stuck open zone valve would do that. Had that the other day!
ah god i wish you were in Ireland! i have climote heating system, boiler fires up whenever it feels like it, even if thermostat set to zero! . already had a motorised valve replaced 6 months ago, and its back doing the same problem again, Just this time itermittently. Plumber said its a wiring issue. yet i cant get an electrician to come near it :( unfortunately, we dont have any "off" switch. best we can do is turn rads right down, and boiler turned down, while we wait for electrician ..... sigh!
Hello mark l have a glow or m flexi on 18
😊 7:59 hello mark my
8:45 8:47