Boiler will not cycle

toddrs93

I have had this problem since last year. The boiler will not start on its own. If I hit the reset button on the aqua stat it will come on and run until it's up to temp and then shut off. The circulator will run as well until it properly cuts off. But then the boiler will not automatically turn back on when it gets below temp. And if I try to hit the reset again it still will not come back on. It takes several hours and then I can hit the reset and it will come on. So basically I can get it to run 2-3 times the entire day. I have cleaned the boiler, replaced the nozzle,replaced the filter, replaced the cad cell relay, and replaced the whole aquastat. The thermostat seems to be working. I'm not sure how much voltage it should be sending to the boiler but there is some voltage on the wires coming from it to the boiler. It is a Milwaukee thermoflo that is probably 40 plus years old. Any ideas?

Zman

It sounds like the boiler is running a "post purge" cycle after the burner turns off. If not it should be.
What is the operating temp and differential? What it the manual reset high limit set to?
Is there a zone valve that is closing that is preventing post purge flow?

toddrs93

Hi is set at 170. Lo and diff I don't remember but it should not matter because the lo/diff function has been disabled since the tankless coil is no longer in use (installed a hot water heater).
No zone valve that I know of.

STEVEusaPA

You probably are going to need a good trouble shooting tech with a meter (or 2) and work thru the aquastat to see what's going on/not going on. Could be anything from a loose wire, bad neutral, bad ground, to a bad control. You shouldn't of had to replace both the aquastat and the primary control unless some electrical event zapped them both.
BTW, what kind of thermostat do you have and how many cycles is it set?

billtwocase

Did you replace the cad cell and mount? Is it an R8182 control, or do you have a L4006E?

toddrs93

I am pretty good with electrical. I have checked all signals and condition of wires, everything is good. It is an R8182. I found the whole thing new and I don't know how old the last one was so that's why I just replaced the whole thing. I don't know anything about the thermostat but it's a Honeywell. I did install a brand new cad cell and mount.

I just checked again and it appears to be a fuel issue or electrode because when I hit the reset, the igniter or transformer whatever you call it, you can here it sparking and I can see voltage at the igniter, but the boiler didn't fire. Yesterday after trying to start it I pulled the electrodes and nozzle out and the nozzle was wet so I assume it's spraying fuel fine. When I replaced the nozzle a couple weeks ago I reset the the electrode position and measured it all and it fired right up. I assume if I did not have the electrodes set right then it would not fire at all.

When I open the bleeder I get a nice clean flow of fuel.

toddrs93

Now its only getting more confusing. So it hasn't been running in like an hour, its 65 in the house and the thermostat is still calling for heat. So I go down and check it and the temp is at 110, relays are open so no power to the igniter or the circulator. I hit the reset and nothing happens, no attempt to start at all. This is the first time that has happened, the reset will always usually kick it on. So I left it be and like 5 minutes later I am downstairs doing something and I hear it kick on by itself, also the first time I have heard this happen. So I monitor it and it gets to 165 and cuts off, which makes no sense because its set at 170 so it should get to 180 and then kick off. 2-3 minutes later I hear it kick itself on again but this time it never actually lights and just turns back off after 30 seconds. Talk about a mind of its own...

776v63

So which control is going off on reset? The aquastat or the cad cell relay? Both? When you say it runs for about 30 seconds and trips off, it sounds like a cad cell reset.

As far as the burner; at the most basic level, if you have oil and spark, you should have flame. In order to get a reliable and consistent flame, you need quality oil delivery and good spark. Just because you have some wetness on the nozzle, and can hear arcing, doesn't mean that either system is working 100%.

There are ways to properly test these systems which may be better left to a professional.

toddrs93

776v63 said:

So which control is going off on reset? The aquastat or the cad cell relay? Both? When you say it runs for about 30 seconds and trips off, it sounds like a cad cell reset.



As far as the burner; at the most basic level, if you have oil and spark, you should have flame. In order to get a reliable and consistent flame, you need quality oil delivery and good spark. Just because you have some wetness on the nozzle, and can hear arcing, doesn't mean that either system is working 100%.



There are ways to properly test these systems which may be better left to a professional.

I couldn't agree more as I see it everyday in my own field as a master auto tech that also manages the shop.
However there are two issues there.
One is that I have had two companies come in, one last year and one this year and both have been more concerned with trying to sell me a new boiler than even attempting to service this one. What I got from the conversations was that they couldn't source any parts for it and they just weren't very experienced with the type of setup.
I know a guy that was very experienced with these old setups but he moved away. He has been helping me diagnose it over the phone and his opinion is that the boiler is just as efficient as today's boilers when its running proper, and its more reliable than today's boilers so that is why I have stuck with it.
The second thing is since I had already bought the aquastat and other parts, no one was willing to come look at it because they said they would not accept responsibility for work I had already done and the parts I had bought. Which I understand because at the shop we don't usually install customer supplied parts.

When it runs for 30 seconds and trips off I mean it never actually fires, flame is not detected so it shuts off.

I do not understand the first question as I thought the cad cell was just the flame detector sensor that completes or interrupts the circuit that powers the ignition relay. I believe I have seen other models with a separate cad cell relay box but I do not have it. The guy helping me said this model must have some kind of weird hybrid setup like a stack relay swith but not exactly. All I have controlling things is the aquastat R8182D and the cad cell eye.

Jamie Hall

Two thoughts -- and keep in mind that I stay away from oil burners; I know very little about them and I'm not minded to learn at my age -- since I have a very competent tech (Charles Garrity) to do that for me. That said...

First, where are you? It is possible that we know someone who could come and take a look and whom we could vouch for.

Second -- keep in mind that the cad cell has to see flame and recognize it and trip the safety circuit in the controller. What may be happening on those 30 second runs is that you are not getting ignition (since you say you don't see flame) and the cad cell also doesn't see flame, times out and shuts things off. There is a delay -- and 30 seconds seems about right -- when the burner will try to light, bypassing the cad cell. So the cad cell and its circuits may be doing exactly what it is supposed to do. Then the question is -- which of the three possible things is wrong that you don't see flame? Air setting way off? Nozzle giving a bad pattern or no flow (nozzle, nozzle screen, pump pressure...)? No or weak spark, of mislaid spark (misaligned electrodes, bad electrodes, short to ground somewhere in the high tension circuits, bad ignitor transformer...). Needs a good tech.

neilc

OP,
excuse me,
I don't think you've answered the question yet,
what reset are you resetting?
is it an ignition controller or burner reset ?
or are you resetting a manual high water temp reset, or ??, low water cutoff ??
just asking,

776v63

ou have a combination cad cell relay and aquastat.

Basically you most likely have an issue with the burner.

Trying a pump bleed as suggested is probably a good place to start.

Here's a crash course in oil delivery troubleshooting.

http://www.grayfurnaceman.com/no-oil-to-burner.html

unclejohn

Have you tried calling your oil supplier? They should have experienced techs. If you want to take another stab at it stab the electrodes and get a new pair. RE Michaels normally has oil burner parts.

cadec

sounds more like a faulty 8182D or bad circulator. doesn't sound like the reset button is actually being tripped Also, he has not mentioned anything about delayed ignition, in which one would think he would have had . And it seems to start ok it's just not running at times when the T-Stat is still calling for heat almost like its running up to high limit but having a really long wait time to get back down I order to kick the burner back on. Is there power at the circulator are you sure it's actually working? it my have power but might not be actually working .

toddrs93

Hatterasguy said:

Can you make a simple test?

Next time when it fails to start:

Open the bleeder and hit the reset button.

Run about a cup of fuel out of the bleeder and close the bleeder.

Reset and try to restart it.

Report back with result.

Ok was busy a few days but back to the issue now. There is no common occurrence here, it operates totally at random. It will come on and fire by hitting the safety reset button on the aquastat and it will fire this way several times, then out of the blue it will stop working. Once in a great while it will come on by itself, but I am talking that has only happened 3-4 times in the last two weeks.

So for the last few days at first it came on ok everytime I hit the reset button (6-7 times), and then finally it stopped working, so I hit the button again and it did not fire so I opened the bleeder as stated in this post and ran a cup out. Then I hit the reset again and it still did not fire.

toddrs93

Jamie Hall said:

Two thoughts -- and keep in mind that I stay away from oil burners; I know very little about them and I'm not minded to learn at my age -- since I have a very competent tech (Charles Garrity) to do that for me. That said...

First, where are you? It is possible that we know someone who could come and take a look and whom we could vouch for.

Second -- keep in mind that the cad cell has to see flame and recognize it and trip the safety circuit in the controller. What may be happening on those 30 second runs is that you are not getting ignition (since you say you don't see flame) and the cad cell also doesn't see flame, times out and shuts things off. There is a delay -- and 30 seconds seems about right -- when the burner will try to light, bypassing the cad cell. So the cad cell and its circuits may be doing exactly what it is supposed to do. Then the question is -- which of the three possible things is wrong that you don't see flame? Air setting way off? Nozzle giving a bad pattern or no flow (nozzle, nozzle screen, pump pressure...)? No or weak spark, of mislaid spark (misaligned electrodes, bad electrodes, short to ground somewhere in the high tension circuits, bad ignitor transformer...). Needs a good tech.

Locattion- I am in Hagerstown, Maryland.

Second, I agree the most likely problem is that it is not getting a signal due to not seeing the flame or the correct temp. Pump was replaced last year, Nozzle was replaced 2 weeks ago, aquastat and cad cell replaced last week. One of the only things I have not replaced are the electrodes, however if the electrode setting was bad or the electrodes them selves were bad wouldn't it not fire ALL of the time? This thing will fire the majority of the time when I manually hit the reset on the aquastat. And on the times it does not fire, I can here a buzzing that really sounds like spark from the transformer/electrodes to me.

toddrs93

unclejohn said:

Have you tried calling your oil supplier? They should have experienced techs. If you want to take another stab at it stab the electrodes and get a new pair. RE Michaels normally has oil burner parts.

RE Michaels has a store right down the street but they refuse to even talk to me because I am not a licensed HVAC tech.

toddrs93

cadec said:

sounds more like a faulty 8182D or bad circulator. doesn't sound like the reset button is actually being tripped Also, he has not mentioned anything about delayed ignition, in which one would think he would have had . And it seems to start ok it's just not running at times when the T-Stat is still calling for heat almost like its running up to high limit but having a really long wait time to get back down I order to kick the burner back on. Is there power at the circulator are you sure it's actually working? it my have power but might not be actually working .

BRAND NEW 8182D and circulator is less than 1 year old, circulator works fine, I am pretty confident in that, voltage checks out, all pipes get hot through out the entire house pretty quick, good flow through all the lines, no air pockets.

Fred

Are you sure you don't have a broken or shorted wire somewhere between the controls (including from the thermostat to the transformer/boiler)? It may be that it sometimes is giggled enough to make contact and at other times it can't.

SWEI

toddrs93 said:

I am in Hagerstown, Maryland.

Is this a steam or hot water system?

toddrs93

Fred said:

Are you sure you don't have a broken or shorted wire somewhere between the controls (including from the thermostat to the transformer/boiler)? It may be that it sometimes is giggled enough to make contact and at other times it can't.

I'm sure its a possibility, though I have checked as much as I can and everything looks good, I have checked signal from the thermostat and it looks good.

This really should not be that difficult to diagnose. I just need the time to sit down to read and understand the theory of operation and look at a complete schematic of how the whole boiler works.

I have the aquastat schematic but I would like to see a full explanation of how this is supposed to work and what signals what along with a full generic schematic of the system from thermostat to electrode.

toddrs93

SWEI said:

toddrs93 said:

I am in Hagerstown, Maryland.

Is this a steam or hot water system?

hot water

SWEI

toddrs93 said:

SWEI said:

toddrs93 said:

I am in Hagerstown, Maryland.

Is this a steam or hot water system?

hot water

Not sure if @Steamhead still services hot water systems, but I would certainly give him a call.

776v63

The part that catches my eye is that you say sometimes the burner doesn't light. If the burner fails to light, there is a problem with oil or spark.

If the burner does light, but goes off on reset after 45 seconds, you have a flame sense issue.

The website I posted before has some great explanation of oil burner operation.

toddrs93

What about the electrodes. Does anybody know if they are worn or if I have the setting just a little off if that could cause it to light intermittently? I think I'm just going to go ahead and order some electrodes anyway for piece of mind.

776v63

Beckett says the tips should be pointy, and the ceramics shouldn't be chipped, cracked or excessively dirty.

A new set is inexpensive, and they come with a gauge and instructions on proper setup. YouTube is a gold mine of how to videos if that is your thing.

STEVEusaPA

It's not the electrodes, but you can change them too. It's been almost 2 weeks, when you gonna call a pro?
If you push the reset button (first of all was it flashing?) and nothing happens, then the burner comes on later, you have a control issue (open limit, bad control) or loose/broken wires.
There are simple ways for a competent professional to trouble shoot their way thru this problem. Then recheck all setting (z dimension etc).
Then after you solve this problem a full combustion test, smoke/draft test, check vacuum/pressure, and your fine.

Vernon

I know its been 6 yrs since the original post, but was this resolved?
I am having a similar issue

SootBoy

Vernon said:

I know its been 6 yrs since the original post, but was this resolved?
I am having a similar issue

i just saw this post today 3/23/2022 andi could throw my two cents in but the good techs are few and far between.. Sounds like a combustion issue. make sure the Cad Cell yellow leads are on correct and flks already walked him through stuff but saying he rest the control making us think it was a control type high limit..the whole time i was reading this i pictured one of those hanging horizontal units in a garage with poor access and dangerous to get up to..