I have some good (young and naïve) kids at a property I let out with this Vaillant boiler and they told me late last week that "it wasn't working". I attended on Saturday afternoon and saw it had F.28 displayed on the LCD and the BAR needle was down at zero.
I have the boiler manual so quickly realised F.28 is failure to ignite - but I wasn't sure whether it had failed to ignite because of low pressure - or because of something else - lack of gas, gas value, condensate etc. - so I started out by re-pressurising the boiler with the internal mechanism (two screws on the underside) - a task that takes around 30 minutes.
Once it was at about 1.5 BAR I reset it and it ignited - I got the Tenants to call for heat and the radiators got nice and hot in a very short while - the pressure needle remained constant and I was happy to leave - saying that they might consider bleeding the radiators at some point (maybe I should not have said that).
Apparently they did bleed the radiators on Sunday... but on Tuesday (last night, two days later) they said it was showing F.28 again and the bar needle was back at zero! I've re-pressurised this boiler before and I know that it lasted many, many months - so this news surprised me, and worried me - why on earth would it lose its pressure so quickly (I started to think about a leak somewhere - but why would that suddenly have occurred?)?
What I don't understand - as I'm not there to watch it - is whether the F.28 happens first and that then causes the pressure loss... or whether the pressure loss happens (leak? pressure relief valve? something else?) and then that results in a F.28.
I remotely talked them through re-pressurising it last night and they're back up and running, but I'm now trying to schedule-in a Heating Engineer to go and look at it - the last GSC was in March 2019, so it's annoyingly just before the next one is scheduled on the 11th March... but I can't risk waiting that long to get the GSC and Service done, I think, it annoys Tenants when they do not have a working boiler - fair enough.
The Tenants have a pre-pay meter (boo!) and one thing I've learned today is that one of the "most common causes" of F.28 is a lack of gas supply... I have mentioned this to the Tenants before so I doubt it's the case again... but there's a niggle at the back of my mind - this boiler is supposed to be built like a tank! When I'm there it seems to behave itself fine - then bang!
I'm not working on this any more myself - I've done all I can, I'll get someone in. I'm also going to have an external filling loop installed (to speed things up) and a magnetic filter. But, for my own knowledge and awareness - would anyone be able to answer my question about the combination or pressure loss and F.28?
Does the boiler fail to ignite at some point, give up and show F.28 and then that results in an eventual loss of pressure, with the needle eventually going down to zero? Or... is it the pressure loss (and who knows why that might be?) that eventually causes the F.28 as it (slowly, I assume) drops from over 1 BAR down to zero?
I have the boiler manual so quickly realised F.28 is failure to ignite - but I wasn't sure whether it had failed to ignite because of low pressure - or because of something else - lack of gas, gas value, condensate etc. - so I started out by re-pressurising the boiler with the internal mechanism (two screws on the underside) - a task that takes around 30 minutes.
Once it was at about 1.5 BAR I reset it and it ignited - I got the Tenants to call for heat and the radiators got nice and hot in a very short while - the pressure needle remained constant and I was happy to leave - saying that they might consider bleeding the radiators at some point (maybe I should not have said that).
Apparently they did bleed the radiators on Sunday... but on Tuesday (last night, two days later) they said it was showing F.28 again and the bar needle was back at zero! I've re-pressurised this boiler before and I know that it lasted many, many months - so this news surprised me, and worried me - why on earth would it lose its pressure so quickly (I started to think about a leak somewhere - but why would that suddenly have occurred?)?
What I don't understand - as I'm not there to watch it - is whether the F.28 happens first and that then causes the pressure loss... or whether the pressure loss happens (leak? pressure relief valve? something else?) and then that results in a F.28.
I remotely talked them through re-pressurising it last night and they're back up and running, but I'm now trying to schedule-in a Heating Engineer to go and look at it - the last GSC was in March 2019, so it's annoyingly just before the next one is scheduled on the 11th March... but I can't risk waiting that long to get the GSC and Service done, I think, it annoys Tenants when they do not have a working boiler - fair enough.
The Tenants have a pre-pay meter (boo!) and one thing I've learned today is that one of the "most common causes" of F.28 is a lack of gas supply... I have mentioned this to the Tenants before so I doubt it's the case again... but there's a niggle at the back of my mind - this boiler is supposed to be built like a tank! When I'm there it seems to behave itself fine - then bang!
I'm not working on this any more myself - I've done all I can, I'll get someone in. I'm also going to have an external filling loop installed (to speed things up) and a magnetic filter. But, for my own knowledge and awareness - would anyone be able to answer my question about the combination or pressure loss and F.28?
Does the boiler fail to ignite at some point, give up and show F.28 and then that results in an eventual loss of pressure, with the needle eventually going down to zero? Or... is it the pressure loss (and who knows why that might be?) that eventually causes the F.28 as it (slowly, I assume) drops from over 1 BAR down to zero?