Furnace stuff

There is plenty to go wrong here, but you can repair it
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

Baseline measurement before cleaning or changing the nozzle. First firing of the season also.

https://youtu.be/oJxys3hUSuM

Then I picked up my 1.00 GPH 80A nozzle and oil tank filter. Cleaned the furance. Reassembled and adjusted the air/fuel ratio. It was in fact too lean and needed to be richened up, as you would expect from decreasing the nozzle size.

https://youtu.be/rtBUXw78GcU

The numbers look good. I will follow up on a cold day just to make sure. Looks like I picked up 1-2% efficiency, too.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

kevm14 wrote: Mon Oct 11, 2021 12:51 pm The numbers look good. I will follow up on a cold day just to make sure. Looks like I picked up 1-2% efficiency, too.
It's 13F out and it has been running for a while so thought I'd check it. I found it a little lean though within the 10-12% range. I richened it a tad and got it back toward 12%. However I need to check again in the 30s because it could end up over 12%.

Conditions. 61F intake air also.
Screenshot_20220108-072230.png

Before. CO was around 8ppm.
20220108_072216.jpg

After. CO dropped to 6ppm. Efficiency went up a tad but probably less than 1%.
20220108_072800.jpg
20220108_072808.jpg
20220108_072812.jpg
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

A little warmer out so I checked again. Looks perfect still. So I guess don't set it up when it's mild out or it will be a touch lean in the cold.
Screenshot_20220109-075945.png
20220109_075907.jpg
20220109_075914.jpg
20220109_075921.jpg
20220109_075926.jpg
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

13 months later, no heat this morning. Tripped out on no flame. Reset it, and, yeah, no flame. Didn't smell oil though.

Transformer/ignitor had a spark per the screwdriver test. It COULD still be too weak to fire across the electrodes so maybe I should see if I can get a long spark, at least 1/2", before concluding it's fine. But I suspect it's fine because it didn't smell like the heat exchanger was being sprayed with unignited oil.

Cracked both the fuel line to the nozzle tube and the bleeder and both had a decent oil flow. When I flipped the burner on after loosening the fuel line, the oil sprayed a couple feet.

If it's a nozzle issue, there are a few scenarios:
1) Oil contamination. Easy to check. If the cork filter is totally plugged up, that's the issue. I would then change all filters, change the nozzle and readjust air band.
2) Clogging/soot on the outlet side of the nozzle. Could be a bad nozzle. Could be an electrode adjustment issue. Could be low fuel pressure. It SHOULDN'T be a misadjusted air band. But if the pump was failing, low pressure could cause a lean condition and soot buildup, a crappy ignition and THEN soot build up. If it seems to be anything other than a bad nozzle, I will have to take an action to prevent it from happening again (fuel pressure, electrode gap).

If the nozzle looks totally fine, then it's probably a failing/failed oil pump that just can't make the proper pressure despite seeming to flow OK when I checked. I would replace the pump and I guess buy the correct gear to check/set the pressure, which is one thing I haven't done and can't do. It should be 100 psi but sources say you can also jack it up to 140 and run a smaller nozzle for better atomization. I'd probably keep it stock though the later model burners (same basic design) seem to do 140.

I'll try to stock some filters and nozzles anyway.

I guess another variable is the water heater seems fine. So you'd think contamination would affect that burner, too. But it could also be on its way to clogging and just hasn't yet because the duty cycle on the water heater is totally different from the furnace.

I have heard of nozzles being bad out of the box. Basically the spray pattern is crap and it never burns right. So while I did adjust the air band for the best overall burn, that doesn't prove the spray pattern was good.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

kevm14 wrote: Thu Nov 10, 2022 9:22 am If it's a nozzle issue, there are a few scenarios:
2) Clogging/soot on the outlet side of the nozzle. Could be a bad nozzle. Could be an electrode adjustment issue. Could be low fuel pressure. It SHOULDN'T be a misadjusted air band. But if the pump was failing, low pressure could cause a lean condition and soot buildup, a crappy ignition and THEN soot build up. If it seems to be anything other than a bad nozzle, I will have to take an action to prevent it from happening again (fuel pressure, electrode gap).
So it was option 2. The brass mesh filter was spotless.
20221110_181241.jpg
20221110_181246.jpg
20221110_181254.jpg

I also peeked inside the furnace using the inspection door and it looked extremely clean. I saw no evidence of any soot buildup so that tells me I had adjusted the air band properly.

Looks like textbook electrode gap issues. OR, the gap was OK, but the spray pattern was shitty and it still built up soot. I need to look up if I am supposed to grind the electrodes to a point or if that matters. They are a bit worn so I may do that. Is it possible the ignitor is getting weak? I guess I still should check to see if it can handle a long gap with a screwdriver.

I removed the nozzle, cleaned it with carb cleaner, blew it out (backwards) with compressed air and it looks like this now.
20221110_182206.jpg
20221110_182208.jpg
20221110_182202.jpg

I reset the gap per the updated Beckett specs.
20221110_182826.jpg

Reinstalled everything. Result? Instant fire.
20221110_184048_HDR.jpg

I think the plan today is still to buy filters and nozzles. I don't have to do the tuneup today. I do plan to replace the nozzle and do my annual cleaning of the heat exchanger. I'll look up if the electrodes should be ground to a point, and probably throw my gas analyzer on it to make sure everything is good after that.
kevm14
Posts: 15200
Joined: Wed Oct 23, 2013 10:28 pm

Re: Furnace stuff

Post by kevm14 »

Did the filters, nozzle, and cleaned the heat exchanger.

Also ground the electrodes and readjusted.
20221112_112744.jpg
20221112_112748.jpg

Items remaining that I should do:
- Consider checking the burn with my gas analyzer. The heat exchanger was extremely clean so that tells me my adjustment last time was good. And in the past I never attempted adjustment except when I decided to change the nozzle size. But since I have the tool....
- I still didn't check to see if I get a strong spark on the ignitor. I'm sure it's fine.

Both of these things are relatively easy. However, today was 71F so way too hot to be doing anything with the furnace.

The oil tank filter was a bit sludgy actually so I think I noted in the past to definitely do that one annually and the individual burner filters can probably go 2+ years.
Post Reply