Vokera Excell 80SP water leaking

[geekbecky]

Hi, I have the above combi boiler in the house we just moved into. It was running hot/cold and had not been serviced for a long time so we had it serviced last week. The service person seemed competent and did a lot of filing to get off deposits. (I couldn't fit in the corner at the same time so am not sure exactly which parts were cleaned.)

Unfortunately the hot/cold problem has not gone away (I'm not sure if he cleaned the flue venturi as seems to be recommended for this problem - I'll look into this and/or query him.)

But moreover a new problem has started: now when I turn the boiler off it slowly leaks water from the main heat exchanger (or one of its washer connections - hard to tell exactly even with the main burner case open.) It leaks until the water pressure is quite low. I *think* this only happens when the unit is turned "off" not when it is left in "rest" mode, i.e. with the DHW on but no demand. There is no noticeable leak when the DHW is working in demand but the pressure does drop after use so perhaps the leaked water is just getting boiled away inside the case?

Perhaps the heat exchanger sprung a leak with all the filing? Or one of the washers needs replacing or reseating? I welcome your comments.

 

[gas4you]

I don't really understand what he would have been 'filing' as you put it.

Generally a standard heat exchanger brush or blade is all that would be used to clean the HE especially on this

It could just be bad luck on his part that there is now a leak, or drip.

Call him back, any reasonable engineer would rather have a happy customer with no drip

 

[Agile]

Its very likely that the boiler has been switched off at the mains with the pilot light left on.

This causes the heat exchanger to overheat and the connections to it to leak. They will usually be quite easy to stop. I would use the existing washers but put silicone grease on the threads. New washers would compress and might need tightening again after a few days which would need a second visit.

The hot/cold cycling needs fixing by a competent person.

Tony

 

[gas4you]

What can you think that he was filing though Tony?

 

[Agile]

I take those comments with a pinch of salt! He may have been doing a little "scraping" !

Usually a stiff brush on the undersides of the HE is enough on those.

Tony

 

[geekbecky]

Thanks for your quick replies and suggestions. He is coming back tonight to look at it, hopefully can just reset and possibly grease the washer connections.

Re: "filing" - I just meant removal of deposits by abrasion causing some "dust" - he was using brushes I think. I'm not concerned about that - sorry about my poor choice of words.

It sounds like I should be leaving the DHW on at all times so the fan runs to avoid overheating? I had been turning the unit off at the mode selector switch to "save energy," not realizing this was causing problems.

Thanks again.

 

[Agile]

You have inadvertently been very silly! I thought there was a warning on the front?

The boiler runs the fan at a slow speed all the time to stop the pilot flame from overheating the boiler.

Turning the selector switch to "off" stops the fan, overheats the boiler and makes it leak!

Tony

 

[DP]

Fit new seals on the heat exchanger.

These seals will not need 'retorqued' at a later date. Existing seals while can be used, they will now be less pliable and liable to break up.