[Steam Boiler] Not turning off after everything is heated?

zeth07

I posted previously about our steam boiler overfilling itself and was told that the tankless coil potentially had holes in it causing the problem.

We replaced the tankless coil but now the boiler/motor is constantly running while everything is now heated properly. It's been running for over an hour and we don't think that's normal.

The boiler has been off for several days while we were working on it, but since everything is now heating properly we're worried about why it keeps running and not turning itself off.

Any idea what would cause this to happen?

Here's model no. info:

https://imgur.com/QWUrBch

Here's old pictures I took previously of the setup:

https://imgur.com/a/25Ooqt8

Jamie Hall

It keeps firing after it comes up to pressure? After it reaches the setting on the pressuretrol for cutout? (not when all the radiation is hot, when it reaches the cutout pressure) (note that i the pressure is still OK -- a pound or two -- and the thermostat is still calling, you don't have a problem -- it's trying to keep you warm).

But if the thermostat is happy and the pressure is high and it won't shut off, that's not good. Not good at all. And potentially very dangerous.

There really are only three possibilities -- the simplest is that somehow the pressuretrol didn't get wired in properly at some point. Second, the pressuretrol is not seeing the boiler pressure -- pigtail nor boiler connection plugged. Third, something is amiss with the burner control and it won't shut down (that's very rare, but it does happen).

Does the boiler shut down if you lower the thermostat to some insane minimum? If so, the third problem is eliminated. If it doesn't, you may still have a wiring problem -- or a control problem. If it does, then it's most likely one of the first two problems.

In any event, I wouldn't run the boiler at all, except in a real emergency (like the house is going to literally freeze), and then only with someone in constant attendance to shut it off with the emergency switch, until I found and fixed the problem.

zeth07

It has already reached the temp on the thermostat and we can feel the radiators plenty hot, and the hot water is hot, so nothing should be calling for hot water for it to keep running which is what we're confused about.

Some of the pipes where the water is running into the boiler where the aquastat is seems abnormally hot but we aren't sure if that was because the boiler was running for so long.

The wiring on the primary control seemed correct when my brother checked cause the previous boiler guy replaced that when we were trying to fix our other problems.

So we are unsure if maybe something is wrong with the new Aquastat that came with the tankless coil, or is it something wrong with the thermostat now that wasn't a problem before, or maybe the wiring on the primary control is actually wrong. Or it's something else entirely.

It would continue to run even with the thermostat OFF and even unplugged entirely.

I'm not sure about the pressure cause the pressure seems low or is supposed to be low cause of the steam, so I don't know how to tell the difference if something is wrong there.

Jamie Hall

Three questions: first, what is your primary control? Are there two terminals marked "T-T" on it? And, if so, what -- if anything -- is connected to those two terminals?

And what pressure do you read, and on what kind of gauge?

And what is the aquastat -- which is, I presume, on a tankless coil? -- set at?

In the meantime, as I said -- don't run it until you figure out why it isn't shutting down as expected, unless someone is right there to keep an eye on it. A runaway boiler can ruin your whole day...

EBEBRATT-Ed

@zeth07

Sounds like something is wired wrong. You need to get someone who knows controls to fix it

zeth07

Jamie Hall said:

Three questions: first, what is your primary control? Are there two terminals marked "T-T" on it? And, if so, what -- if anything -- is connected to those two terminals?

And what pressure do you read, and on what kind of gauge?

And what is the aquastat -- which is, I presume, on a tankless coil? -- set at?

In the meantime, as I said -- don't run it until you figure out why it isn't shutting down as expected, unless someone is right there to keep an eye on it. A runaway boiler can ruin your whole day...

Here is the old primary control, it had 6 wires before but the guy said it was ok to have 3 when he put on the new one:
https://i.imgur.com/7pLHH4j.jpg

Then the new one that was installed is this one:
https://i.imgur.com/NeduoQT.jpg

For the pressure, we have this but it's an old pic from when we were having other problems but it's still the same thing:
https://i.imgur.com/pYD6CFD.jpeg

It shows slightly above 0, which from what I've read is actually correct for Steam boilers and what we've been told previously cause the pressure was only supposed to be in the decimal point range at 0.2 or 0.5.

The aquastat was set at 160, but when my brother talked to the previous guy who came to work on it he said he usually sets his to 140. So even after changing that it was still running very hot. It apparently goes to 200 max though.

This is the old Aquastat:
https://www.supplyhouse.com/Honeywell-L4006A1009-High-or-Low-Limit-Aquastat-100-240F-range-5F-Differential-4585000-p

This is the tankless coil that was bought which came with the new aquastat:
https://www.ecomfort.com/Weil-McLain-386700350/p49939.html

It's hard to find information on it but this is apparently the model for that aquastat:
honeywell L4080b1311

Here is the wiring of the primary control, ignore the blue tape that was from my brother trying to figure out if it was all hooked up correctly:

https://imgur.com/a/0qGPOjZ

Jamie Hall

In the photo of the new control, I see the two yellow wires for the flame sensor and two black wires connected to T-T. I don't see three wires... Where do the two T-T wires go? And how is the aquastat hooked into the circuit?

I can't make head or tail out of the spaghetti bowl of wires and wire nuts...

Honestly I think you may be in well over your head. This is not a difficult wiring job, but it does have to be done right -- and neatly -- by someone who understands what he or she is doing.

And i reiterate: do NOT run this boiler without someone in constant attendance ready to shut it off if it runs away until you get the controls figured out and you can verify that both the pressuretrol and the low water cutoff are wired properly.

zeth07

Jamie Hall said:

In the photo of the new control, I see the two yellow wires for the flame sensor and two black wires connected to T-T. I don't see three wires... Where do the two T-T wires go? And how is the aquastat hooked into the circuit?

I can't make head or tail out of the spaghetti bowl of wires and wire nuts...

Honestly I think you may be in well over your head. This is not a difficult wiring job, but it does have to be done right -- and neatly -- by someone who understands what he or she is doing.

And i reiterate: do NOT run this boiler without someone in constant attendance ready to shut it off if it runs away until you get the controls figured out and you can verify that both the pressuretrol and the low water cutoff are wired properly.

There are four wires technically on T-T. Two black wires go to the Aquastat and two other ones white/yellow are going to the thermostat. The boiler guy said this was because it was hooked up as emergency heat, as in originally before we bought this house but nothing has changed with that on our end that we would mess with the wiring besides however the boiler guy did it when he hooked up the new one.

The primary control was hooked up by the actual boiler guy cause he replaced the old one. It wasn't something we were messing with until this was going wrong and we were just trying to double check if it was hooked up correctly and now here we are.

Here's a better picture of that:
https://i.imgur.com/DXhCSZQ.jpg

My brother is technically an electrician so actual wiring wouldn't be a problem to do, it's just a matter of figuring out what's actually wrong with it now.

We tested the thermostat wiring and the wire itself has continuity so it seems ok there at least.

EBEBRATT-Ed

@zeth07

Someone sold you the wrong aquastat. The one you have makes contact on a temperature rise. You need one that breaks contact on a temperature rise.

You need a L4006a or whatever the new equal model is.

Probably why your running all the time

SuperTech

A Honeywell L7224U will be a perfect for what you need for an aquastat.  That primary control is not correct either. The original primary control was an interrupted ignition control that used an oil pump solenoid for pre purge. The replacement that was installed just turns everything on the oil burner on and off at the same time, this means that the ignition components are being powered the entire time the burner motor is running, which is a waste after ignition has been established.  It also puts unnecessary wear on the ignition components. A R7284U would be a better replacement for the original primary. 

zeth07

EBEBRATT-Ed said:

@zeth07

Someone sold you the wrong aquastat. The one you have makes contact on a temperature rise. You need one that breaks contact on a temperature rise.

You need a L4006a or whatever the new equal model is.

Probably why your running all the time

It came with the tankless coil when my brother went to replace it since someone else said it would probably cost us $1,000 to get someone to do it. So when looking for the correct coil that must've been what he found but I guess he could've saved some money finding it without that if it was wrong.

I don't know how reusable the old one is besides just getting a new one if the old one still worked anyway.

Thank you for the heads up though.

SuperTech said:

A Honeywell L7224U will be a perfect for what you need for an aquastat.  That primary control is not correct either. The original primary control was an interrupted ignition control that used an oil pump solenoid for pre purge. The replacement that was installed just turns everything on the oil burner on and off at the same time, this means that the ignition components are being powered the entire time the burner motor is running, which is a waste after ignition has been established.  It also puts unnecessary wear on the ignition components. A R7284U would be a better replacement for the original primary. 

We'll look into those. I think the primary control was what the boiler guy had and I'm thinking he didn't really know what was wrong or the correct thing if he wasn't as experienced with steam boilers. It sounds like that's something he should've known about anyway and was maybe just trying to change things that weren't really needed on us for more money cause that seems like a real oversight to sell that to someone who doesn't need one like that. But who knows I'll give him the benefit of the doubt.

Thanks for the info.

zeth07

We got the R7284U as recommended. Would anyone know how the wiring of the R7284U is supposed to go in regards to a L4006A1009 Honeywell Aquastat?

It's our old one we are going to try since the other one that came with the tankless coil wasn't correct so we want to try the old one that might not have been the problem before we figure out if we need a new Aquastat as well.

This is the old Aquastat:
https://www.supplyhouse.com/Honeywell-L4006A1009-High-or-Low-Limit-Aquastat-100-240F-range-5F-Differential-4585000-p

Here is the install instructions of the Aquastat:
https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1249544835101/Honeywell_L4006A1009_Installation.pdf

And this is that primary:
https://www.supplyhouse.com/Honeywell-R7284U1004-Universal-Digital-Electronic-Oil-Primary

Here is the install instructions of the primary:
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/R7284-INSTALL.pdf

Most of it is color coded which is easy enough for my brother, but we're confused about how the Aquastat is supposed to connect to it. There are two wires coming off the Aquastat, so are they supposed to go into Limit and L1? Or something else entirely?

Previously they were hooked up to the T / T on the primary along with the thermostat wires together. Do we do that again or do they go somewhere specific as mentioned?

We just need clarification because otherwise my brother can handle doing it. We don't want to mess something up when we can otherwise do this ourselves.

SuperTech

One thing that I would check first is the configuration of the R7284U primary control.  You can set this control up for TT configured on or off. You want TT configured off. If it is configured on the burner won't shut off when the call for heat ends.

zeth07

SuperTech said:

One thing that I would check first is the configuration of the R7284U primary control.  You can set this control up for TT configured on or off. You want TT configured off. If it is configured on the burner won't shut off when the call for heat ends.

When the primary is set with the TT configuration to OFF it will stay off even when the thermostat is calling for heat (says 70 and set to 75 for testing reasons.)

When the primary is set with the TT configuration to ON, it is constantly running even if the thermostat is already at the temperature it is set to (says 70 and we set it to 68 for example for testing.)

Even with the thermostat actually OFF and no one running anything for hot water the boiler/pump would still run.

That's why we think there's some confusion with the wiring, or even something else is wrong. We've tried everything and with all the other problems we don't know what could possibly still be wrong when it otherwise seems to be working correctly.

Jamie Hall

Well, I have no idea where my reply went. Try again.

Troubleshooting sequence.

Take all the wires off of T_T. The burner should be off. Now place a jumper across T_T. The burner should turn on. Take the jumper back off. The burner should turn off.

If this step is OK, then the primary and its setup are fine. Otherwise, it's a problem in the primary or its setup.

If step 1 is OK, go and take the thermostat off the wall and leave its wires there unconnected. Go back down and connect the thermostat wires to T-T. The burner should NOT turn on. If it does, the thermostat wires are shorted. Assuming that it does NOT turn on, go back upstairs and connect the thermostat wires together. The burner should turn on. Disconnect the thermostat wires from each other. The burner should turn off. If this step is passed, the wires are OK.

If step 2 is OK -- or problems found are corrected, connect the thermostat to the thermostat wires. Turn the thermostat up to call for heat. The boiler should turn on. Turn the thermostat way down. The boiler should turn off. If tiis step is OK, the thermostat is OK. If not, there is a problem in the thermostat.

With the thermostat cleared, turn it up and run the boiler up to steam temperature. Turn the thermostat back down. Now take the two wires from the aquastat and disconnect them from the aquastat. Connect them to T-T. The boiler should NOT turn on. Go to the other end and connect them together. The boiler should turn on. Disconnect them from each other. The boiler should turn off. If this doesn't pass, there is a problem in the aquastat wires.

If step 4 is OK, connect the wires back to the aquastat and let the boiler cool down -- may have to actually turn it off. Leave the thermostat down. At some point the boiler should turn on, called by the aquastat. Let the boiler run up in temperature. Before it gets to steaming, the aquastat should shut it off. If this doesn't work there's either a problem with the aquastat -- or the aquastat is wired incorrectly.

zeth07

Jamie Hall said:

Troubleshooting sequence.

We will try this, thank you for the response as always everyone.

zeth07

SuperTech said:

One thing that I would check first is the configuration of the R7284U primary control.  You can set this control up for TT configured on or off. You want TT configured off. If it is configured on the burner won't shut off when the call for heat ends.

Jamie Hall said:

Troubleshooting sequence.

Just replying back again to say that a combination of both of these things seemed to have solved the problem.

While we did try having the TT configured on the primary as both On/Off and not capable of figuring out the problem still, with the checking of the thermostat wiring we were able to figure out that as the source of the problem.

However the new thermostat was wired appeared to be incorrect, as when the two wires were held together it would clearly start, but when it was wired "normally" it wouldn't run correctly.

We decided to put the old thermostat back on and have it wired the old way it was before and then everything seemed to work fine after that. Along with the TT configuration on the primary being set correctly.

So while the problem is fixed, I'm curious to know how the new thermostat was supposed to be wired, given the fact that it was just two wires?

The old thermostat wiring is just the two wires hooked up to R and E.

With the new thermostat the combinations we tried didn't seem to work the same way with the two wires. I don't know what combinations my brother tried but they weren't correct for it to function properly.