Wallstar Oil Boiler

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Suffolk
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Hi all

New hear, just got a quick question.

I went to see a customer today who has a problem with their boiler. First start of the day it goes through the normal process but goes to lockout. After opening up the exterior cover, the clear oil pipe has a large slug of air in it. When the lockout is reset, the boiler works fine. Only when the burner cools down for a period of time does the sequence start again. Ive checked the oil tank and they have plenty of oil.

One thing i did notice was after the burner had been running for a while and it was turned off, the oil started to disapear through the valve which i now know is a combined fire and non return valve. As im new to oil boilers, it was the first time i had come across this type, and i decided to fit a normal non return valve in addition to the fire/non return valve. The oil is not disapearing any more, however when the burner is running, it seems to pull a lot of air through with it.

Beacuse of this i spoke to HRM directly and they said it could be a loose joint allowing the air in, or indeed the pump (the pump is an older type delta pump)

As time was getting on this afternoon and not wanting to get a problem later in the day, i decided to come back next week to change the fire and non return valve. Customer happy with this as boiler is working allbeit after the first start up.

My question to you is what do you think the problem could be? Im hoping by changing the fire and non return valve that the oil wont dissapear and will lessen the air coming thorugh the oil line.

I have been told by HRM that it could possibly be the pump thats letting air in as well. As im new to this and have yet to change a pump, could someone give me some guidance to chaning the pump? As the delta pumps arent available, it will be a direct replacement danfoss pump.

A huge learning curve for me, certantly nothing like this came up on the oftec course!!

Any help much appreciated
Cheers
Andy
 
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If you've cleaned all filters and no other blockage in fuel line (eg ice,crap) then the pump, flexi or fire valve could be at fault. Impossible to say which without seeing it. I'd check all pipe joints are good, then change the f.v. and flexi as these cheapest options, then pump. I've had all of these give similar probs to what you describe.
Oftec is a good thing to have under your belt but now the learning curve gets very steep. Welcome to the real world and good luck. Stix.
 
thanks for that stix, ive got the fv and already have a pump in stock. Looks like doing a bit of searching on here regarding wallstar boilers, the air in the oil line can be a common problem.

Just for my information, if the pump is getting old and worn, im guessing its not going to have enough power to 'suck' the 2.5m that it can when they are new, and if this is the case does air get drawn in?

A huge curve as you said, 6 months in and its starting to get busy servicing wise, with now the repairs starting to come in!

Cheers
Andy
 
If a pump can't maintain pressure its either fecked, not getting a good fuel supply or not being driven properly (thats presuming you've tried adjusting the pressure with your gauges). Faulty pump seals can allow air to be sucked in where there is no head of oil. If the air is coming from the tank end you've either got a poor joint in the fuel pipe somewhere,faulty component or the bubbles are coming out of the oil due to too high a vacuum.
 
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bit of an update

went round this week and relaced the nrv, tightened up all the joints and got the burner going. No air bubbles in clear line. Got a call today that on first call it still goes to lockout, after pressing the lockout button, fires up as normal.

Going back next week and will check the nozzle, electrodes, pump pressure co2 etc to mkae sure thats ok; it could just need a service!

Im then going to check the soleniod valve to make sure thats not playing up. The pump is drawing the oil through very well, so am unsure if its a pump problem. I read on here that with sterling burners it could be the capacitor causing problems.

Im thinking that its going to be a process of changing parts to get it going.

is there anything ive missed checking or indeed a better process to identify the problem?

cheers
andy
 
It could be the capacitor failing which is denoted by the motor humming before spinning or not spinning at all, or it could be the pump drive dog worn(the bit that joins the pump shaft to the motor shaft).

spraggo
 
Thanks Spraggo

Will check that when i go back next week. Anything else thats obvious that i should be looking for?

cheers
andy
 
Thanks Spraggo

Will check that when i go back next week. Anything else thats obvious that i should be looking for?

cheers
andy


I take it that you have a combustion anyliser, pump pressure gauge, etc to check the obvious. Has the boiler been serviced lately :?: ;) ;)
 
Spraggo

I do have all of those bits, boilerhasnt been serviced for a couple of years from what i believe, so was planning to do that the same time i was there

cheers
andy
 
take a new danfoss oil pump coil, as they can breakdown when hot, but work perfectly when boiler reset, also make sure the blast tube is really clean, no soot between vanes.the photo cell needs all the help it can get to see the flame on these burners, due to low sulphur fuel altering flame colour. according to hrm tech.
 
thanks Stumpy

I have one of those in the back of the van, though the pump thats on the burner is a delta pump. Do i need to change the pump to an danfoss pump for the coil or can the coil go on the delta pump?

cheers
andy
 
thanks Stumpy

I have one of those in the back of the van, though the pump thats on the burner is a delta pump. Do i need to change the pump to an danfoss pump for the coil or can the coil go on the delta pump?

cheers
andy
Danfoss do a brilliant book which has ALL the conversions in them, or go on their website, a known fault with the wallstar is the clear flexiline ..can you twist it with your fingers? if you can then it can draw air in that way
& Welcome to the Oil engineers fraternity!!!
 
djsarge

thanks very much for the advice. The clear flexiline doesnt seem to twist in the fingers, when i was there last time i had no air going through the flexline, just the standard bubble. Will certantly go to the danfoss website and try to download the booklet.

Once again, thanks for the help

cheers
Andy
 

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