Oil boiler not working as expected

mmills06

I have been having issues with my oil boiler system for the past few months and I am looking for some advice for potential solutions. Quick summary is that I am having trouble with the boiler staying hot, low limit does not seem to fire the boiler and once below the low limit a heat call from the thermostat will not fire the boiler either. Once the temp is above the low limit the system operates as expected.

Here is an overview of my system:
• Weil McLain oil boiler, Beckett AFG burner, tankless coil
• Honeywell R4184 D 1027 oil primary
• Hydrostat 3250+ (new, just installed)
• Taco SR503 (new, just installed)

Background:
I purchased this house a few months ago and had a service tech out to clean the boiler (which hadn’t been cleaned in a few years). During this cleaning the tech advised that the entire system should likely be replaced soon, including the oil tank. They stated that there was sludge in the tank which they diagnosed because after the cleaning and filter replacement the oil flow was too low. They blew out the line and the brand new filters already looked black. Anyway, after this cleaning and blowing out the line the boiler operated fine for a month or so.

I had the service tech out again about a month later for a no heat call. The taco relay was not lighting the zone red LED even though the thermostat was calling for heat. Stated could be a bad board, solution was that they found a short in one of the thermostat wires from a separate zone. Boiler worked intermittently after this. In the following weeks I would notice that the boiler would occasionally not fire even though there was a call for heat. The red zone light on the Taco board would not be on, and the boiler would be below the low temp limit. I hit the reset switch to manually fire the boiler and once the boiler got up to a certain temp, it would turn on the Taco zone light and circulator. Boiler would then fire as long as there was a call for heat before the temp dropped.

During this time, I noticed the aquastat (Honewell l1824a) was not firing the boiler at the low limit of 160 and would not stop the boiler at the hi limit of 180, boiler would fire to 200 and then shut off. This week I had the service tech out to replace the aquastat. They installed a Hydrostat 3250 and replaced the old Taco SR503 with a new SR503 (ZR/ZC wired from the 503 to the hydrostat, 180 hi, 160 low, 0 economy, Z/I switch set to Z).
One day later, I turned down the thermostat (which I had kept high in an attempt to keep the boiler operating by staying above the temp that seemed to keep it running) and the boiler temp dropped down to 120, when the thermostat called for heat there was no light on the sr503 and boiler did not fire. I hit the manual reset button and the boiler fired, once it reached 160, the sr503 zone lit up and the circulator started. The system then worked as expected as long as there was a call for heat before the boiler dropped below 160. Same situation the next day after using shower, boiler dropped to 130 and had to be manually started but then operated as expected once temp got up to 160.

I am planning to replace this system, new boiler and indirect water heater as well as potentially a new tank. However in the meantime I am trying to limp along with what I have. What are we missing here? Is there something else that could be tripping the boiler to not fire? Tech states it likely has to do with the sludge in the tank but I cant understand why because the system operates as expected as long as the temp stays above 160. Any thoughts or recommendations would be greatly appreciated, thank you!

Jamie Hall

Well, to start with it has nothing to do with sludge in the tank. That may give problems, sometime, but not this kind of problem (the only way to determine reliably when an oil tank needs to be replaced is an ultrasound thickness check, which your oil company -- if you have a regular one -- should be doing, and certainly can do).

The problem you are having is a control problem (assuming there are no error lights or such on the ignition control). Somewhere in the chain of circuits something is not telling the burner to fire. I suspect a significant miswiring problem -- most likely wiring to the Taco, but possibly in the aquastat. Someone, like a competent tech. (the one you have isn't, if he thinks it's a sludge problem) needs to check each step of the chain -- what calls the burner to fire? What tells that control that the burner is needed? etc. and find what isn't connected properly or what isn't working properly.

HVACNUT

If you need to hit the reset button on the burner, then it's a burner or fuel delivery issue. 
Throwing money at it won't fix it. The tech needs to actually diagnose the problem. 
That primary is obsolete. If you've got more disposable income, invest in a modern primary with a 15 second safety. If you opt for a Riello with the new system, trial for ignition is 5 seconds. 
Have you researched new systems yet?

Jon_blaney

Is there any particular time of day when the system fails?

mmills06

Thank you Jamie, HVACNUT and Jon!

Jamie Hall said:

Well, to start with it has nothing to do with sludge in the tank. That may give problems, sometime, but not this kind of problem (the only way to determine reliably when an oil tank needs to be replaced is an ultrasound thickness check, which your oil company -- if you have a regular one -- should be doing, and certainly can do).

The problem you are having is a control problem (assuming there are no error lights or such on the ignition control). Somewhere in the chain of circuits something is not telling the burner to fire. I suspect a significant miswiring problem -- most likely wiring to the Taco, but possibly in the aquastat. Someone, like a competent tech. (the one you have isn't, if he thinks it's a sludge problem) needs to check each step of the chain -- what calls the burner to fire? What tells that control that the burner is needed? etc. and find what isn't connected properly or what isn't working properly.

Jamie,
That is in line with what I was thinking (but also aligns with what I want to believe) that this was a wiring issue potentially around the ZR or whatever should be calling the boiler at the low limit. I believe the tech just swapped out the 3250 for the L1824 and the new sr503 with the existing wiring setup, it fired so he thought job well done. It wasnt until after he had left that I noticed the low temp issues.

HVACNUT said:

If you need to hit the reset button on the burner, then it's a burner or fuel delivery issue. 
Throwing money at it won't fix it. The tech needs to actually diagnose the problem. 
That primary is obsolete. If you've got more disposable income, invest in a modern primary with a 15 second safety. If you opt for a Riello with the new system, trial for ignition is 5 seconds. 
Have you researched new systems yet?

HVACNUT,
So I know that the reset on the boiler is typically tripped for fuel issues, I have only ever seen that used before when there was no oil to prime the line. For this situation, I hit that button to fire the boiler (started up immediately and ran fine) to get the temp up above the low limit. That said, could definitely still be an issue there it just seems like too much to be a coincidence that the boiler would trip only below the low limit and run fine if it stays above it. Tech never mentioned anything about the primary though I do see that it is an old one and due to be replaced. But as you mention, I am not trying to throw too much money at the existing system that I know should be replaced. I have not done too much research for this specific replacement. A couple years ago, I had a new system installed in our old house which was a Buderus boiler w/ Riello burner, SuperStor indirect water heater. Had great experience with that system after it was installed until we moved. The company that my tech is from gave me a quote for a new system using a Trio PurePro P3, Riello burner, Bradford indirect water heater as well as a new oil tank install. I will likely look to gather a few more quotes.

Jon_blaney said:

Is there any particular time of day when the system fails?

Jon,
It seems to happen specifically mid-day, when there is a longer time between heat calls allowing the temp to drop.

Jon_blaney

Do you have the install booklet for the hydrostatic? If not, it is online. I would check the install. Read carefully.

Jon_blaney

I would set the Z/I switch to I not Z.

STEVEusaPA

The ZR/ZC wiring for the hydrostat are not necessarily a direct swap out for ZR/ZC on other aquastats.

HVACNUT

@mmills06, coincidence or not, neither the Hydrostat, Taco zone panel, any circulator, or thermostat can possibly put the burner into safety. 
There's something wrong with the burner, or the fuel, i.e. clog, leak, etc.
The actions (or lack thereof) of the Taco panel and Hydrostat could be just because the burner is in safety. If boiler temp is below the Lo limit, then ZC will not send 120v to the Taco relay. 

mmills06

Jon_blaney said:

I would set the Z/I switch to I not Z.

Hey Jon, so the tech had actually set the Z/I switch to I. When I first discovered the low boiler temp issue, the thermostat was calling for heat, boiler was at 120 and not firing, but the sr503 was lit and the circulator was running. Turning the switch to Z stopped the circulator. I believe that for my setup (tankless coil) this should have been set to Z so that the circulator would not run until the low limit was satisfied. I have the booklet, will look at the wiring.

HVACNUT said:

@mmills06, coincidence or not, neither the Hydrostat, Taco zone panel, any circulator, or thermostat can possibly put the burner into safety. 
There's something wrong with the burner, or the fuel, i.e. clog, leak, etc.
The actions (or lack thereof) of the Taco panel and Hydrostat could be just because the burner is in safety. If boiler temp is below the Lo limit, then ZC will not send 120v to the Taco relay. 

Thanks again @HVACNUT . I guess here is my question. How would I know if the burner is in safety? I guess I am not sure if the burner is tripping (safety?) or just not firing because the wiring is correctly calling for heat. I turned the thermostat up again yesterday and have been monitoring. There have been no interruptions, boiler fires up when call for heat, stops at 180 and then re-fires back at 170. Though the temp has not dropped below 160 (at the expense of cranking through oil I'm sure).

HVACNUT

mmills06 said:

I guess here is my question. How would I know if the burner is in safety? I guess I am not sure if the burner is tripping (safety?) 

Well on your primary, the red button pops up when it goes into safety. If the button is flush with the top of opening, then it's not in safety. If the button is above the opening, then it is in safety. 
Just for S&G's, the next time it happens, instead of pressing the button, just wrap your knuckles on the top or side of the primary. If the Fonzie trick works and the burner starts, then it's a faulty primary and you can get a 21st century control. 

STEVEusaPA

HVACNUT said:

@mmills06, coincidence or not, neither the Hydrostat, Taco zone panel, any circulator, or thermostat can possibly put the burner into safety. 
There's something wrong with the burner, or the fuel, i.e. clog, leak, etc.
The actions (or lack thereof) of the Taco panel and Hydrostat could be just because the burner is in safety. If boiler temp is below the Lo limit, then ZC will not send 120v to the Taco relay. 

Technically it could (and I’ve seen it). It’s not the case for the OP, but put on your thinking cap and tell me one way.

leonz

Speaking as a homeowner with many oil burner and oil horror stories, I do not trust these oil companies as many of them have a high employee turnover rates and simply push selling service, oil tanks and parts.

I have had 2 hydrolevel aquastats fail in the past and the second one turned off the low water cut off function when I was standing in front of it.

I removed the "second" failed hydrostat and replaced it with a Honeywell L8124L and a B+G McDonnel and Miller RB-122-E low water cut off which is the first electrical control for the boiler that shuts the boiler off in the event of a water loss.

I have a single thermostat for controlling the temperature in my home and a tankless coil.

I have had no trouble with my heating system since 2016.

There are companies/small firms that filter fuel oils as a profession using a filter cart and in the process pump the oil through multiple filters and flush the sludge out of a fuel oil tank.

My first question would be, is the chimney protected with a cap? My second questions would be, did they inspect the flue breech for a blockage or the chimney for a blockage?

From your description you have a single pipe bottom draw system. If your oil tank or fuel line does not have one already you need a firomatic valve.

The tank should have a top draw oil delivery system to avoid plugging the line and filter with oil sludge and
it should be converted to a 2 pipe system which returns unburned fuel back the tank. The top draw system sacrifices a small amount of fuel oil by keeping the suction line off the bottom of the tank.

The other thing is that you should be treating the fuel oil with POWER SERVICE 911 fuel treatment which can be purchased by the consumer at Tractor Supply and other retailers.

Removing a failing tank is a real nasty expensive business as all the old oil has to be pumped out and then the tank has to be cut open to fully expose the belly of the tank.

All the sludge has to be collected and scraped and scooped out and any remaining oil has to be soaked up with approved absorbent rags and these rags and gloves placed in the 15-gallon barrel.

The inner walls of the tank have to be sprayed with a citrus solvent to dissolve any remaining oil and then the oil is wiped up and the tank wiped down with more solvent to clean it. After all the rags and sludge are collected and the steel lid and locking band installed on the barrel it is taken to an approved waste oil disposal company. After all that the clean tank can be taken to a scrapper and sold for scrap.

STEVEusaPA

@leonz I disagree with almost everything you typed. I really wish many of the non-professionals would emphasize all their experience and advice comes mostly from their own situation. Without knowing all the particulars of that situation (we're only getting one side of the story), I'd hope the OP and anyone else who stumbles upon this post gets advice from competent professionals.

mmills06

HVACNUT said:

Well on your primary, the red button pops up when it goes into safety. If the button is flush with the top of opening, then it's not in safety. If the button is above the opening, then it is in safety.
Just for S&G's, the next time it happens, instead of pressing the button, just wrap your knuckles on the top or side of the primary. If the Fonzie trick works and the burner starts, then it's a faulty primary and you can get a 21st century control.

@HVACNUT, thank you again. So I am thinking that you may be right on this with the safety. I am trying to remember if the button was popped up but either way I think you are right.

Update:
I tried to simulate the problem again today by turning off the thermostats and running the hot water in the bath to drop the temp of the boiler. This time, the boiler did in fact fire at 150 and run until 160. I then turned on the thermostat again and the boiler fired as expected with the circulators running for the zone until the temp was reached at the thermostat. Ran this test twice at different times of day, same result. All that to say, it seems to be working as it is supposed to.

I am guessing that HVACNUT was correct and that there burner shutdown and I only noticed it happening below the temp and then firing the boiler manually got it back up to temp and started working. Sorry guys! So yeah I guess that may bring me back to the problem of being either the burner or the tank/oil/sludge. If it is the tank or oil quality, is it worth cleaning/treating the tank or just replacing. I know that is dependent on the individual situation but I guess I am just wondering if cleaning/treating is ever a good option. Tank replacement quote was in the ballpark of 5k so I just want to understand if it is worth investigating other options before replacing.

Jamie Hall

Odd how various people have varying experiences with oil companies. We did change the company serving the properties we care for about 7 years ago, when the company we had been using was purchased by an out of state big firm. Their service was still good, as was the oil they sold -- but their delivery system (we have automatic for each property, and pre-buy) was a catastrophe. Bad software, not bad people.

The company we have now is local, but has been in business for the last 70 years or so. So far, so good.

On fuel oil -- you get what you pay for. The quality is actually much more variable than one would like to think. Yes, it is all number 2 and meets those standards, but how about sludge? Water content? Bacterial overgrowth?

On underground tanks. Nothing wrong with them -- if they are installed properly, which means double walls and spill alarms. Not worth the expense for a residence.

On top draw vs. bottom draw. Both are fine, if your fuel is good quality. Bottom draw has the advantage that it is usually easier to prime if you need to work on a filter or something -- or you run out. All our properties are bottom draw, and we've never had trouble with them.

Oh and one more thing -- the main property we care for -- Cedric's home -- did have an underground tank (2,000 gallons) and we had to remove it back in about 1990. State regs. didn't permit them any more for residences. We were and remain sorry to see it go. And Cedric is only the 4th boiler on a system which has been running for 92 years now,,, (he would be only the second, had a local plumber not managed to destroy a perfectly good WM 580 by poor installation, back 20 or so years ago).

mmills06

I should have mentioned, this is a 275 gallon tank in an unfinished basement, about 15 feet from the boiler.

leonz

STEVEusaPA said:

@leonz I disagree with almost everything you typed. I really wish many of the non-professionals would emphasize all their experience and advice comes mostly from their own situation. Without knowing all the particulars of that situation (we're only getting one side of the story), I'd hope the OP and anyone else who stumbles upon this post gets advice from competent professionals.

================================================================

It is too bad they did not paint the installation date on your oil tank as it would have made things easier.

It is too bad that we are not burning alcohol for heating fuel as it would be much cleaner and simpler to use. Sadly Henry Ford did not push back against the oil companies as he was already using alcohol for fuel and they wanted him to use gasoline as it was a byproduct for refining crude oil into kerosene.

The oil in your tank can be filtered and sludge flushed out when the oil is filtered as well using a filter cart.

http://ph.parker/us/en/portable/filter/carts

I do not see what is wrong with what I have mentioned which is based on my past experience hiring extremely expensive "professionals" and the proper disposal of oil tanks per current regulations.

I guess I could go into the huge benefits of having an exterior skid mounted 275+ gallon Highland Tank Within a Tank and using a 2-pipe system oil delivery system; wherein oil could be purchased in a greater bulk quantity and how a 2- or 10-micron RACOR 500FG fuel filter would be of great benefit to the end
user as the water and any dirt and algae would be centrifuged out and drop to the drain as it enters the filter housing and is then pulled through the filter cartridge that is rated for 10,000 gallons.

One of the many reasons I gave up on suburban propain was they let me run out of fuel four times and the furnace tech almost broke the drop in filter housing on my fuel filter and he spent more time talking to his wife about their upcoming vacation than cleaning and testing my Buderus Logana G205? boilers combustion efficiency.

Having a filter cart would show a great deal of good will to your customers and provide a better way to protect a customers oil heating system and also be a guaranteed money maker as you would be filtering the oil in the tank annually and breaking up any sludge and pouring in POWER SERVICE 911 fuel treatment for a flat rate charge as it takes 30 minutes per 275 gallon tank and you change the filters only when they become plugged.

Having a 15 gallon DOT barrel with a locking band in the service truck for plugged filters and rags would be a plus.

The filter carts can be equipped with 110 volt or 220 volt pumps and have a retractable cord reel mounted on the cart so there is no need to carry an extension cord.

The filter carts can be equipped with an oil analysis system showing the customer how clean the oil is after it is filtered.

Yeah, but what do I know; I have no real world experience dealing with fuels on a daily basis.

EdTheHeaterMan

@leonz, I might agree with you, that you have experienced one tank removal. However is your Tank removal going to go exactly like @mmills06 tank removal (should he choose that route)? Your experience is helpful to us here, but it is not the only way to deal with a tank removal. There are some tank removers that will work for less. There are individual conditions at each location that may cost more that other locations. I believe that Steve has experience more than just one Tank Removal. I have also experienced more than one Tank Removal. I can tell you that many of those tanks were recycled properly with much less expense.

One of my tank removers in South Jersey would filter the old oil in a tank and donate it to a local church that would find church members in need, and give the oil to the needy. He was very reasonable for this task. The old oil in his situation was not sent off to a waste oil company that charged dearly for the hazardous waste disposal. Another tank disposal firm that I would recommend was a little more expensive but also recycled the oil himself and was able to sell the fuel to waste oil burner owners at very low rates. He operated on large commercial tank removal with all the necessary licenses and permits. He also did the small residential tank removal at affordable rates. So, your experience may have been a little overkill by a company that followed all the rules associated with a large commercial tank removal. If you shopped it around, you may have found a better deal with the same result.

I am also not a fan of the Hydrolevel combination Aquastat relay/LWCO. But I would have opted for the Honeywell L7224U for all the additional features and lower cost.

leonz

I have been very happy with my Honeywell L8124L and my Bell & Gossett TB-122-E and have slept very well since I had them installed.

mmills06

UPDATE #2:
So the boiler tripped again today, can confirm it is the r4184 d safety. The red button was up, hitting the side of the primary 'fonzie' trick did not work. Pressing the red button fired the boiler and has worked fine since (last few hours or so).

Frustrating. At this point could definitely be a problem with the primary, the burner, the motor, or it could the sludge from the tank causing issues with flow I guess. Who knows. As I mentioned, I am planning to get this whole system replaced. Called a few places to learn more about oil tank cleaning vs. replacement. Trying to understand if there is any saving the tank replacement or if I just bite the bullet. I am getting sick of never knowing when this thing is going to trip.

Thank you all for your input and help! Really do appreciate it!

pecmsg

I don't think you've had a real tech yet!

Before jumping the gun get a "Qualified" tech to go thru the entire system. Change the filter, make sure the screen is clean, check the nozzle (replace if needed) check pump pressure. Perform a combustion analyses.

Jamie Hall

pecmsg said:

I don't think you've had a real tech yet!

Before jumping the gun get a "Qualified" tech to go thru the entire system. Change the filter, make sure the screen is clean, check the nozzle (replace if needed) check pump pressure. Perform a combustion analyses.

Agreed. It would be wise to get a knowledgeable technician to go over the system, rather than an ambitious salesman which is what you seem to have had so far.

EdTheHeaterMan

The reset button will fail ONLY if there is a flame failure (or a perceived flame failure) by the Cad Cell flame sensor or the primary control it is connected to. All the other problems you describe sound as if that has always been your problem. Circulators not running because the water temperature is too low is a result of a flame failure. Water temperature below expected setting is a result of the flame failure. If the burner stops operating, then nothing else will run. That is how your system is designed. As far as the Oil Tank is concerned, If there is a really nasty amount of tank bottom deposits, then an oil delivery can cause the flame failure. Fuel deliveries can make all those tank bottom deposits become suspended in the fuel and get picked up in the fuel line and get to the nozzle and cause problems.

As far as cleaning that stuff out. I have experience with a tank cleaning machine. Often there is so much junk on the bottom of a 30+ year old tank that when you remove it, the pinholes at the bottom of the tank have nothing to plug them up. Then the tank starts to sweat oil thru those pinholes. Then you have an environmental emergency to replace the tank NOW!

How old is your tank? More than 20 years? And you do not know what the previous owner put in that tank! Maybe he got low price oil or free oil from persons unknown who switched from oil to gas and let someone pump all the crap from the buttons of all those tanks into the bottom of your tank. So many unknowns. Look at getting a temporary tank (like a 55 gallon drum) and having it available to use when you run that tank out of oil. Then that tank is less expensive to remove.

Operate your heater from a spare tank for the few days it takes to replace that tank with a new tank. Have the new tank filled with new oil from a reputable oil company that includes fuel tank additives to prevent rust and corrosion from the inside of the tank.

Once the spare tank is empty, then connect to the new tank.

I offered that service to many of my customers and saved them big bucks on all the Remediation and Hazardous Material removal involved in a tank replacement when there is a lot of fuel left in the tank.

Under NO circumstances would I ever pump oil from an old tank into a new tank. That will just put your old tanks problems into your new tank. You don’t want to spend thousands of dollars to wind up with the same problems.

From an experienced fuel oil tank putter inner.

Mr. Ed

MaxMercy

mmills06 said:

UPDATE #2:
I am getting sick of never knowing when this thing is going to trip.

The basic maintenance of the AFG burner will solve 80% of a random safety shutdown symptom: dirty pump screen, dirty nozzle, electrodes worn and rounded and gapped too far apart.

A technician can service that burner in short order and change the filter.

Even if it's running normally, there are many things that can be checked that can indicate the problem. Is the ignitor/transformer putting out sufficient voltage? An arc test can determine if a weak ignitor/trans is causing delayed/no ignition. Are the electrodes properly shaped and set to the correct dimensions? Open the bleeder on the pump. Is the stream solid, dark red, and free of a pink cloudy air bubbles? A slight leak in the oil piping (that may not leak liquid) can introduce air into the system and cause delayed/no start.

I would plumb in a pressure gauge into the pump and watch the pressure. If it's running at set pressure (100 lbs or more depending on initial setup) and remains stable for 20 minutes, I'd be satisfied the pump and pump coupler were fine (I've seen pump couplers start slipping after 5-10 minutes and drop the pressure).

I would also open the cad cell circuit and measure the cell resistance as the burner is running. If it's solidly below 500 ohms the flame is strong and bright enough to satisfy the cad cell - it it's floating above 1200 ohms, I'd investigate why (could be a bad cad cell or a flame/mixture issue).

Testing the combustion numbers can indicate a problem area even with the burner apparently running properly.

So even if it's running without a safety trip, a technician can often find the problem by checking those things.

offdutytech

Have you changed the filters and looked at the old filter to see if there is any rust or sludge on the old filters and in the canister? Just did service at an oil company for their unit heater last Friday and by Monday after they topped off the tank with clean oil the unit stopped working. Pulled the filter and found rust flakes on the filter. Showed the owner with one of his guys there. His guys wanted to just clean the tank and put fresh oil in it. The owner who has been in the business 40 plus years said nope time to replace the tank. We took a few sample bottles and filled them up to find rusty tank flakes. Maybe get some oil samples from the bottom of the tank. 

EdTheHeaterMan

@ron Don't Hold Back... Tell us what you really think of the current administration!

and when you said

"and you said "alcohol" which only means any organic compound whose molecule contains one or more hydroxyl groups attached to a carbon atom. You didn't define which alcohol to use as a fuel so I assume you meant ethanol, and not methanol or isopropyl, or propanol, or butanol."

My vote went to Capt. Morgan But If all you have is Scotch, then I'll have to roll with it!

Jamie Hall

MacAllan for me. Or Drambuie, if all that is wanted is a wee dram. One other thing about alcohol -- assuming one means ethanol or methanol -- as in camp stoves and the like. The stuff is a fire fighter's nightmare. Clear flame, so you can't see it, and water doesn't help much to extinguish it. (the clear flame bit is a problem with hydrogen, too -- a hydrogen fire is plenty hot, but you can't see the flame).

Erin Holohan Haskell

EdTheHeaterMan said:

@ron Don't Hold Back... Tell us what you really think of the current administration!

Please hold back. No politics here. Thanks.