Seeking advice, new to boilers, boiler broke over winter

triode

https://forum.heatinghelp.com/discussion/comment/1893576#Comment_1893576

This solution looks nice. Question, I am guessing I will have to break a 1/4" gas line off from the main gas inlet somewhere, as the main gas valve (controlled by S8610U #2) pilot also is controlled by S8610U #2, and therefore that pilot line will have no gas until it gets signal on TH-W from S8610U #2. Does the pilot gas valve controlled by S8610U #1 have a thermocouple to prove it has lit?

I ask as I did not see any mention of a thermocouple connection on the V8046C1006 pilot gas valve that was mentioned. How does the S8610U #1 know when that pilot has been proven?

Steamhead

You have it backwards. Module 1 connects to the pilot terminal of the main gas valve that's already there. It sends 24V to the PV terminal on that valve. This sends gas to pilot #1, proves the flame, then sends 24V to module 2. The line to the V8046C that leads to pilot 2 is teed off the line to pilot 1, and the V8046C does not let gas go to pilot 2 at this point.

When module 2 gets 24V, it opens the V8043C to send gas to pilot 2. Now pilot 2 gets its gas, and when it lights and flame is proven, module 2 sends 24V to the main gas valve terminal MV, and the main burners will light.

109A_5

No thermocouples.

OK the way that @Steamhead describes is not what I envisioned drawing the last drawing. It may work the way he describes. However this returns to the unknown of 'will the Gas valve's pilot circuit support two pilots'.

The way I drew it the autonomous pilot gas valve has it own gas source. Like repurposing the taps at the gas manual On-Off valve. So the autonomous pilot gas valve proves first, module #1. With an autonomous pilot gas valve that has it own gas source it really does not matter which actual pilot proves first, it just becomes a matter of the sequence and MV wiring.

As you can see there are different ways to get this done. One down side of this method is if only one pilot proves (the first) you have the equivalent of a standing pilot and no heat until it is realized some thing is wrong. Using the logical AND relay method it does not easily have that scenario, but it is more wiring.

triode

@109A_5 how does a pilot prove without a thermocouple or some kind of feedback?

109A_5

Each S8610U Intermittent Pilot module has its own pilot. And ignites its own pilot.

Each S8610U Intermittent Pilot module has its own igniter spark rod with the pilot assembly which verifies the flame via Flame Rectification detection in the module through the spark wire.

Each S8610U module works autonomously as far as each pilot is concerned. So in this case both pilot assemblies would need to be replaced not just the one, maybe that is where the confusion lies. With a standing pilot (which you do not want) that would use a thermocouple. S8610U Intermittent Pilot modules do not use thermocouples.

If you wanted to reuse one of the pilot assemblies you would need to have a standing pilot.

Steamhead

@109A_5 said: "If you wanted to reuse one of the pilot assemblies you would need to have a standing pilot."

The Y8610U kits do come with an electrode that fits most pilot assemblies. But if I were doing this, I'd get new pilots- either the Honeywell/Resideo Q345U or Q3451U if they are target types, or the Q348U or Q3481U if they're batwing type. The 3451 and 3481 come with built-in spark leads, the other two do not and need separately provided spark leads.

109A_5

Looking at the picture of the kit, you basically need two kits, module, spark wire, spark assembly, wiring harness (or you could fabricate your own second wiring harness)), you just don't need that gas valve type that comes with the kit as a second gas valve (if you go that route).

Another thing with the kit is I don't see a mounting assembly for the pilot assembly.

Also looking at the kit I don't see the actual pilot, so maybe they assume you just remove the thermocouple stuff and replace it with the spark assembly. Maybe the spark assembly slides in where the thermocouple stuff was (hopefully).

I was envisioning the kit came with a pilot assembly like this below. Apparently not.

Steamhead

@109A_5 said "Another thing with the kit is I don't see a mounting assembly for the pilot assembly.

Also looking at the kit I don't see the actual pilot, so maybe they assume you just remove the thermocouple stuff and replace it with the spark assembly. Maybe the spark assembly slides in where the thermocouple stuff was (hopefully)."

You nailed it- the spark electrode assembly replaces a standard thermocouple.

109A_5

Interestingly the documentation shows this, so I guess you get what you get.

triode

Hello, finally back on this unit, I replaced the auto fill, back flow and am now trying to install/wire the new y8610U, the problem is that there was a lot of activity in the room, some wires were knocked around, and I am not 100% sure if what was there is "correct" I am uploading a schematic of what I think was there. Is this how I should wire it back?

I have no idea what the mystery box is, but I am including a picture of it. I think I should replace the thermostat, I have no real way of checking it without firing up the boiler. do they fail often? It sure looks like it may be old.

This is the diagram I have:

This is the Mystery Box:

The relay on the mystery box can not possibly work, as it is broken. Should it work, or did someone just hack and slash this box to use the transformer on it to power the thermostat (the user interface). I have also never seen someone use all RED wires for line and neutral before.

Thanks.

EBEBRATT-Ed

Relay (mystery box) looks trashed. For starters you need to move the circulator "hot" wire to terminal #4 on the relay, keep the transformer hot on #4 as well. Then you need to put a jumper between terminals #3 and #1 on the relay. 120 volt hot stays on terminal #1.

What is the UC1 ignition control? and what other limit and safety controls do you have?

triode

Sorry about that, the UC1 is a Tjernlund Products, Universal Control 1, it turns on the blower motor fan (it has a power fan for exhaust). https://tjernlund.com/product/uc1-universal-control/

The relay box (mystery box) is more than just a relay though, I think?? I think the small box on the left is a transformer for the user interface (thermostat)? Is this a generic thing I can purchase?

EBEBRATT-Ed

Yes the relay is a Honeywell product Supply House.com. If you are not using the X & X terminals you can get a RA89A Honeywell relay.

Tjernlund has different models

950-8804-UC1-Universal-Control-Board-Kit-Version-X.06-8505017-Rev-D.pdf

of the UC-1. Don't know if the wiring has changed between models. See the attached or look on their site

triode

Aha. I did not have this picture, but I see clearly now.

Ok, totally solved the mystery box issue.

https://forum.heatinghelp.com/discussion/comment/1902930#Comment_1902930

I forgot to answer, I think the only other limit/safety control (outside of the UC1, which seems to just start the exhaust blower) is the thermostat, which seems like it is 40+ years old.

On the UC1, it says on the outside 3/4HP, Job code 02181506. This might not mean much, but this picture looks exactly like mine: https://www.supplyhouse.com/Tjernlund-UC1-TJERNLUND-UC1-Universal-Control.

triode

I am still seeking advice on the thermostat (the one with the probe in the boiler)… should I replace that thing, or just try to turn it down until it opens to see if it works (not sure if it goes that low)? Not even sure what they are really called, when I look up thermostat at supply house, well, I get like 1000s of things that do not look like that :)

Steamhead

https://forum.heatinghelp.com/discussion/comment/1902994#Comment_1902994

Aquastat.