HRM Wallstar pulling too much air through

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Hello all,

Am new to this, as in the past I've usually found the answer is past forum threads, this time its got me stumped though!

I've had two seperate engineers (£££'s) and new parts (pump, NRV, electrode block & blast tube) and the boiler will not run for any longer than 2-3 mins. Both engineers said the boiler had them beat and couldnt suggest anything other than replacing it.

Basically, to get the boiler to fire, I have to bleed the line - it fires up and i close the bleed screw, after a minute the burner starts to splutter so I open the bleed screw again, this lets out more air and the boiler continues to burn for another minute. If I don't open the bleed screw again a minute later, too much air builds up and the boiler goes to lock out.

I and the two engineers have replaced and checked all joints. The fuel line has been replaced and a NRV fitted. the boiler was setup originally as a two pipe system with a tiger loop, but is now a one pipe system (as reccommended by HRM).

You can visibly see a lot of air bubbles being sucked through the clear inlet pipe. Could this be a faulty fire valve, or is the pump knackered? Or is it something else? Oh yeah, there's about a fifth of a tank of oil there.

Any help would be much appreciated from you guys, as the missus keeps banging on about it and I've spent circa £400 so far! :rolleyes:
 
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Oh good grief.

Ok rip the lot out. These boilers don't need a tiger. electrode block and blast
tube where a complete waste of time unless there was some other fault.

Get a small drum and fill with kero. Insert pipe into drum and connect
to NRV of boiler. Run boiler. See how you go with that.

The boiler should be able to prime itself with just the bleeding you normally
do. Sounds like you have an air leak in the piping to the boiler at the moment that is allowing the pump to drag in air.
 
Don't you have to remove the circlip in the pump when running two pipe system?

So shouldn't it be put back in when going back to 1 pipe?

Just a thought.
 
hi dcawkwell - thanks for advice, will try that, if it works sweet as a nut, does that mean it will probably be the fire valve that is letting air in? Or possibly the tap at the bottom of the tank? (although if that was leaking air would that mean that I should have oil escaping there? which I don't think it is.

hi xr4x4 - thanks for the speedy reply, the circlip (horse shoe shape?!?) has been replaced to return it to a one pipe system
 
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hi dcawkwell - thanks for advice, will try that, if it works sweet as a nut, does that mean it will probably be the fire valve that is letting air in? Or possibly the tap at the bottom of the tank? (although if that was leaking air would that mean that I should have oil escaping there? which I don't think it is.

hi xr4x4 - thanks for the speedy reply, the circlip (horse shoe shape?!?) has been replaced to return it to a one pipe system

Could well be something restricting the flow. You can then add bits
in until you get the problem. Could be fire valve. Could be dirt in the tank.
Could be piping. Just have to get the thing running first before you can
find the problem.
 
You can shut off the tank valve and connect an oil syringe to the pump connection, then suck. You will soon see any air bubbles.
 
For there to be air in the flexible pipe, there needs to be a faulty joint or valve, which may not leak oil under gravity. Prime suspect is the NRV at the boiler, as the gland deteriorates. Because it does not have a gravity head to it, no external leak will be evident. When you replaced this, did you also replace the rubber insert washers as recommended?
 
most common on these is the fuseable fire valve to be leaking air in .

Because these oil pumps are generally working under negative pressures any leak in the oil supply will cause air problems.

And often lead to pump failure!!
 
Because these oil pumps are generally working under negative pressures any leak in the oil supply will cause air problems.

And often lead to pump failure!!

Pumps fail, negative pressure or not.
 
Hi,JIMBOB80,
I have the same problem .Please can you let me know how you get on.Good Luck!
electricdave
 
Any oil pump working at higher vacuum reading will be prone to excessive wear, air ingress will indeed aggrivate pump wear and could cause premature failure!! ;)
 
Likely cause of this air leak is the fire valve. Either replace the two o-rings on the stem, or replace the valve. My view is to replace the seals, that way you start again with two nicely formed seals. If you replace the valve you never know how squashed they are.
 

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