Problem with underfloor heating

[honeybee]

Hello,

I am hoping some of you experts could help shed light on the issue.

We got a wet underfloor heating system installed downstairs and kept radiators upstairs. Now the boiler is acting up. It comes on a lot, even if we turn off the radiators. Also, every night it goes off and a burner failure light comes on.

It is an old thing, from 1989 made in W Germany, but we got a whole new pump put in it last year. We also have a separate electric balloon that we use in summer for showers etc.

Any ideas on what is wrong? Because of the boilerbissues, we had to leave the whole system turned off. We did get antifreeze put in, but I am worried about the pipes in this weather and angry that the system does not work smoothly - the installer is less than helpful and just says it I'd our boiler problem

What do we do? Should we get a new boiler, and if so, what type? Are these things very expensive?

Thanks so much!

[honeybee]

Sorry for the typos, the iPad doesn't let me scroll down to correct.

We are back in UK now and worried about leaving the heating off. We would have wanted to leave it on antifrost mode, but know that the boiler would have stopped working within a few hours, so no point.

[honeybee]

I've doing a bit of research. Do you think it would make sense to have one balloon for hot water for the kitchen, showers etc. And then an electric boiler and balloon combo for the ufh and radiators?

Something like one of these http://www.boilerguide.co.uk/articles/electric-boilers

Are these available in France? Could we buy one from UK (please don't flame like the other poster who asked about UK boilers!) and are running costs high?

We bought oil in December and it was expensive! A grand or so for a thousand litres. Surely this can't be more expensive to run...

[Richardbk]

It seems that you have 2 separate issues. The first concerning the UFH set up. Should the boiler be coming on  lot ? - possibly yes in this cold weather and if there is no timer fitted, or if the house insulation is poor (including below the floor). 

The 2nd problem seems to one of burner start up. These types of ignition failure are common in most boilers from time to time (gas or oil). It could need just a service and electrode clean/reset, or perhaps spart part such as a faulty valve (in the gas) or maybe a new jet(oil). If the burner is completely unserviceable (possible if it is the original) then in many boilers you can just replace the burner unit.  I know for example in many of the de dietrich (had 2 houses with these) that it is quite easy to change the burner,and even change from gas -> oil or the other way. Of course a new boiler will be much much more efficient, but only you can decide on whether the payback will be worthwhile. Even a new burner will be significantly more efficient than the old one.

[BIG MAC]

Could simply be a ropey thermocouple duping the boiler into thinking it needs to fire ..then cycling till it hits overheat and conks out....or it could be a sticky fan ...could be a very cheap repair ....then again could be a pcb...lets think positive...worth getting a technician out sooner than later though.

[honeybee]

Thanks Richard and BigMac. We are not in France at the moment, and while we were there, the weather was quite warm.

Is it possible that the boiler comes on so much because the water tank is too small for the amount of water required for ufh?

We left the system turned off when we left, because of the daily 'burner failure' issue. Got antifreeze put in though. Hope the pipes are ok, as the house is not that well insulated (gulp).

[BIG MAC]

Not sure what you are talking about in respect of a water tank as I would imagine it to be a sealed system ...the only tank in this case would be the ballon and it wont make much of a difference other than on overheat ie. if the temp sender tells the boiler to shut down because the water is too hot. actually ...thinking about it...worth checking that motorised valves are ok. Your boiler will be sized to heat the system and you have said you have isolated part of it...it may be that the boiler is measuring the temperature of the return water and is closing down on overheat. I would suggest purging the system and checking operation of diverters, replace thermocouple / s as possibly de sensitised, recharge- chemically dose system then balance it properly with all zone stats at proper set points.

[honeybee]

Aaarghhh, BigMac. I can hardly wait to see my plumber's face when I pass on your suggestions:)

[BIG MAC]

Do pass on my apologies as without seeing the installation it's very much a shot in the dark. As a contractor however I can tell you that so often these days people are cajoled into changing boilers it's beginning to wind me up. I have a 15 year old Wrcester Bosch 280c at home ..I have replaced a pressure vessel and machined the flow switch 'flap' to give it a little more clearance, straightened a couple of fan blades (bent by me hosing moss of the roof and accidentally shooting water down the chimney....So about £70 in repairs thus far...I think I may have put a thermocouple in because I had it lying around...I can guarantee there would have been 'engineers' who would have told me 'scaled up' instead of dirt in flap valve body, 'leaking heat exchanger' for silly sod hosing roof and 'failed combustion gas test get a new one' instead of bent fan blade. Boilers are relatively simple things other than the electronics...whoever does your work I would tell them to explain it to you 'like you are 6 years old'.and don't agree until you truly understand what they are going on  about.

Bon chance!

Mac

 

[honeybee]

BigMac,

You are so right...the ufh installer wants me to change the boiler without carrying out checks to try to identify the problem.

Now thanks to you and Richard, at least I know some thing he should test, and hopefully can start a dialogue. Right now I am just being stonewalled!

[Chancer]

My boiler in the Uk must be at least 30 years old, I have owned the house 25 years and it looked pretty ancient then, its a cast iron Glowarm one I think.

I have had it serviced a few times but only by people who I know and trust that arent going to trot out the old "you need a new one", it gets done every year now by a Corgi registered neighbour for the landlords certificate, during that time I have probably replaced the thermocouple on " occasions.

My other friends have on average been tricked into replacing their boilers every 5 years or so, the frequency is increasing with the crappy electronics controlling condensor boilers, had they came in to being in the 60's or 70's when electronics was in its infancy I could understand the frequency of failure but I am convinced it is built in obselescence.

MY boiler has a thermostat and thermocouple controlled manual gas valve, i did have to clean the thermostat contacts once in 1986 as the arcing was interfering with my radio no other work at all.