HRM Wallstar, intermittent locking out when cold

[TheKeymeister]

I've got a problem with my HRM Wallstar (Sterling 40 burner so I'm told), its locking out first fire in the morning, the problem started with the cold weather just before Christmas. One reset used to be enough to get it going, lately that's become 2, 3 or 4 so I decided to look a bit further into it.

Nozzle and electrodes were black with soot, presumably due to repeatedly failing to fire. Electrodes were set wrong which I have corrected and also cleaned up the nozzle. Baffles etc were not too bad but I've given it a good clean out while I was there. Control box and motor capacitor were replaced last year for new items. EBI transformer doesn't look deformed so assumed working, it looks fairly recent too. Pump solenoid bells out OK resistance wise and you can hear it clicking in. It does sound a bit whiney when running, I wondered if it was the pump or drive coupling on its way out (it's the original Delta pump, 20yrs old now) but I put a pressure gauge on it when it locked out today and got a nice steady 110psi (book states 115psi as a base value).

I did notice when connecting the pressure gauge the port was dry with no sign of oil, there was a small amount of leakage through the adapter's threads when I ran it up, and when I disconnected the gauge (after waiting for the pressure to dissipate approx 10 seconds) there was a good amount of oil dripping out. Not sure whether this is normal behaviour, so I'm wondering whether it may indicate air getting in, I can't see any bubbles in the flexi line, but it's an old type one and it does twist at each where it is crimped which I've heard could indicate a problem.

For how much it costs I'm planning on changing the flexi line, nozzle and electrodes and seeing how I get on, they all look past their best anyway so it can't hurt, any other suggestions while I've got it all apart?

PS Before anyone asks no I'm not Oftec registered, however I have had experience with oil burners years back before moving on to diesel gensets, I'm no expert by any means though hence why I'm here

 

[oilhead]

Never seen a Delta pump on a Wallstar, and doubt if it is the original, but they do lift sufficiently. If the hose is pulling in air at the pump, you may not see bubbles, and you can also lose fuel overnight through the pump shaft seal. It's worth checking there.

 

[oilboffin]

You don't need to be OFTEC regd how far up the wall is the boiler,how old is the oil pump it may help to put on a danfoss and also to check on air leaks.Bob

 

[TheKeymeister]

Pump looks original (house built 1997), from the manuals I can find online the early Wallstars came with Delta's before changing to Danfoss soon afterwards. Bottom of the unit is approx 1700mm off the floor and oil tank is about 10m away.



Although it hadn't locked out this morning there was a huge slug of air in the flexi, I know they usually run with a bit of air in it but this was huge and wasn't there at all last night when I had the gauge on it. I think I may add a new non return / fire valve on to my list of bits to change. If that doesn't solve it, it sounds like it'll be a new pump.

 

[oilhead]

Try new hose and NRV first. Also, use new seals on the NRV, although you should see bubbles if you have an air leak there. It is also worth checking that there is no non return valve at the tank as this can be too much for the pump to pull through.

 

[TheKeymeister]

The bits came today so I've gone out and put in a new combined NRV and fire valve, and a new flexi line. I've probably got the wrong flexi line as it's angled at one end (presumably meant for the pump end) but my pump has a right angle adapter screwed in to the bottom so I've had to put the angled end at the top of the fire valve, and now the red plastic lid doesn't fit properly!

Even though I assembled everything with red Hylotite sealant I've got a slow stream of very small bubbles coming through, I suspect it's the connection on the 10mm copper as the previous olive had compressed the pipe slightly and the new one wasn't a very tight fit, I probably didn't help things when removing the old olive either. There's enough length to cut the pipe and still be OK so I'll try that tomorrow.

I dropped the pump off while I had it all apart, I'm not sure if it's normal but when turning the drive shaft by hand there's a definite hard spot. I thought this might be the cause of the noisy running but now it's all back together it sounds normal again. I may keep an eye out for a pump anyway, they seem to come up occasionally on eBay at a good price so it's probably worth keeping one in just in case. I did that with the central heating pump, managed to pick up a good Alpha 2L for a fiver!

 

[TheKeymeister]

Just to follow up from this, I took everything apart and resealed it, and got almost no air bubbles coming through (maybe one difficult to see tiny one every 30 seconds). I was still waking up to a flexi line full of air in the morning and a locked out boiler.

I managed to pick up a brand new pump on ebay for £35 delivered (it came from Wolseley too!). It fitted OK, but had to go on a slight angle to allow the high pressure fuel pipe to fit properly. I set the pressure to match the previous one and bled it, and I've not had any trouble since, it'll be a week running tomorrow with no lockouts so I think I've fixed it

 

[oilhead]

Sounds good. I did say in a previous post that air can ingress at the oil pump.

 

[TheKeymeister]

I'm back, again....

All was going well until about a week ago when I (stupidly) ran out of oil. A neighbour advised me to tilt the plastic tank forward by shoving a brick under it to get me going, and it subsequently fed a load of water and sludge up to the pump. I drained the tank out, removed 40 litres of water, fitted the filler cap plate properly so it didn't let water in, and filled with clean heating oil. Changed all the filters, bled it through, and all was fine.

The only trouble is, the oil is draining back down into the tank after it stops running, its only taking a couple of hours to empty the clear line at the boiler.

Does it sound like I've messed up the new non return valve by sucking water and crap through it? Or have I broken something more serious? I've remade the joints at the tank end for the filter etc, a couple were leaking after I sorted the tank and filter out. No air bubbles are coming through when it's running.

 

[TheKeymeister]

I spent yesterday morning stripping it down, removed the pump filter and solenoid stem and cleaned both up.

I then took the non return valve off, couldn't find any crap in it, so I tested it by firing a load of water through it backwards, and it started coming out the other end which it shouldn't. A bit of work with AC90 and twiddling the ball in the valve got it to improve but not be 100% as it should be. I tested the old valve that I replaced a few weeks back, and it was perfect! Couldn't fit it though as the olive is well crimped on and the bottom nut is a different size but I'll get it back on and send the 'new' one back...

 

[oilboffin]

Oh god last time you take notice of an idiot next door 1take off oil line and back blow it to the tank.2take off the pipe and non return valve.3strip the hose assembly but don't take the non return to bits wash it out,if you need to get a new one and then reassemble using heldite and ptfe to seal
the joints.4 you may need to chage the oil pump.By the way looks like an electro burner you've got
so you need a danfoss pump.Bob