Firebird C26 combi - Grief after water in oilpipe

[Bigands]

Last spring I made the mistake of tipping up the oil tank when the level was low - it eventually stopped working & I assumed oil had ran out, totally forgot about it until last week when we filled with oil & tried to restart !
To cut a long story short I had a full line of water in pipe - this I discharged (full bucket full) & eventually got it working. Next day I started it up & it failed on the 12 second priming stage. Oil pump had stuck - took case off (gearing) & started & the motor turned fine, refitted top casing & after getting shut of more H2O in line, got it started. THEN noticed pressure had dropped to nothing !? filled up with tap & within a few hrs its back to nothing. There are no leaks from pipes/rads etc, so pulled out expansion vessel & pressed valve centre to check if any pressure in there - H2O came out so I'm assuming diaphragm is split.
Question : if it's split & I open refill tap, shouldn't it just fill vessel totally, then once full, I should see pressure go up then it should stablise UNLESS I've got a leak somewhere else ?
Has anyone else made this mistake & if so what bother has it caused (injectors, pumps etc)?
Cheers ade.

 

[Agile]

How much water did you let out of the expansion vessel? You should let a lot out in case its just a little there.

But that has no connection with your water in the oil pipe woes which are totally your fault for tipping the tank and not draining off water from the tank regularly.

Does not help waiting until its empty before you refill it. I am sure you know that!

Tony

 

[leakydave]

The "Water" could have included a lot of muck that could have blocked the bronze filter at the back of the nozzle. Change the nozzle. Do yu have a pressure gauge to accurately measure the oil pressure? If the pressure falls away it could indicate further blockage in an in-line filter farther down the line.

 

[oilhead]

From your post, I can't work out if the burner is still working but you have no system pressure, or the burner is not working and you have no system pressure. The two problems are unrelated. If burner not working, you need to check whether the freed pump is actually producing pressure. Often, water in the pump can cause premature wear in the helical gears that produce the pressure at the nozzle. Also a change of nozzle is recommended as sludge can impede the rotor that atomises the fuel.
If your expansion vessel has failed, then filling to pressure and then operating the boiler will expand the water and eject it through the safety valve. When it cools, it will contract to nil. You need to replace the vessel.

 

[Bigands]

Sorry - because I seem to have several things going wrong at once, it was quite difficult to make myself clear. I've found the reason for the pressure drop - kaput relief valve (it was o.k. but with fiddling around with the boiler, I brushed/pressed the head & let a bit of water out - now it presumably won't seat in correctly and stay's slightly open hence the drop (at least this is an easy fix).
I'm still not sure about the vessel from the weight, it feels pretty full of water, there is a dribble when valve is pressed - what's the best way to check if it's still functional.
Re nozzle - I'm guessing these are cheap to buy but expensive to have changed - complex job ? impending redundancy means I'm looking if poss to sort it myself (forgive the sob story !) thanks so far to agile, leakydave & oilhead

 

[Burnerman]

The expansion vessel is really just a steel box with a rubber diaphragm in the middle.....water on the boiler side, air up to the scrader valve.
So, it seems that the diaphragm has gone AWOL so it needs renewing.
With the new vessel, adjust the air pressure to around 10 psi (or whatever is recommended) before connecting the water pipe. Any foot pump will do this.
The pressure relief valve may reseat if you operate it again - or it may not....could be worth a try!
The burner nozzle is easy enough to replace, but do order the correct one before you dismantle.....they cost around £6.
John