trap on condensing oil burner melted

johnjoe 123

was at a job last week and the trap on the bottom of the boiler actually melted. . im told your meant to fill the trap with water when installing any of yas come across this yet??

heinbloed

You're yoking, are you ?

Micky Dolenz

Yes, you need to prime/fill them first. They can be tricky to fill and fit, I nearly always just pour water down the flue.

Sparkpea

????????????

heinbloed

How hot would the flue gases have to be to melt the plastic trap? Popably made from PP (polypropylene)? 150 degrees Celsius for half an hour?
Where is the condensing part here?

The flue pipe would have melted as well.

Billy Bunting

Filling with water is new to me, must have missed that bit in the manufacturers instructions, is this the case with all these

heinbloed

The first filling of the condensate trap is meant to allow for the pressure differential to work in a safe modus.
The initial fill is not meant to act as a delay fuse for the plumber to get away before the thing becomes dangerous.
Never run a condensing boiler in a non-condensing modus.
Read the manual. If you don't understand it - fingers-off !!

@the OP: decomission the installation. Isolate it.

JohnnieK

Billy Bunting wrote: »

Filling with water is new to me, must have missed that bit in the manufacturers instructions, is this the case with all these

It is recommended by the manufacturers that the trap is primed because it is possible that POC's could come out through the trap and into the atmosphere, so filling the trap will prevent this. Why it melted on this instance is beyond me. They are usually well away from the heat source and condense is only luke warm at best.

I think it's best he contacts the manufacturer because it dont sound right to me.

heinbloed

JohnnieK wrote:

It is recommended by the manufacturers that the trap is primed because it is possible that POC's could come out ...

PAHs they're called, smiley. Or maybe PAHCs (poly-aromatic-hydro-carbons)
No, they won't come out because the condensing boiler works on a negative pressure. The negative pressure is maintained by a ventilator pumping out gases. The ventilator's spin (rpm) is controlled by the pressure differential. Only if this fails the PAHCs might come out of the condensate trap - if it isn't filled with water. But in this case the boiler would switch off anyhow. The pressure differential would sense if there is a hole in the system, if the trap is empty.
And the lambda probe would 'smell' the risk as well.

Unless we have a total failure of all safety devices as in case the OP has described.....CO poisoning included

@the OP:

What type of boiler is that? Brand and model?

yoshytoshy

Surely the trap would evaporate over a summer month ,when the boiler might not be used.

Sparkpea

never heard of priming the trap before..

how can it melt? the boiler is well insulated, the chemical doesn't effect plastic, the trap is plastic..

DoneDL

Its always in the MI`s that the condensate is primed, stops the POC going past the trap, I have heard of this though I didn`t hear the outcome but the technical dept. will put you right. It could be excessive flue gas temperature which would probably be too much for the plastiic to cope with.