Intermittent s8610u functioning

VanPlumbing

Hi there, I'm having a situation with intermittent voltage getting to a s8610u. Everytime I get a call back, there is no power for ignition to the console even though I can confirm power output from the transformer.
Here's the interesting bit; if I jumper the transformer power directly to the console it will then start up flawlessly and work fine even on restart. It then works fine for a few hours and stops again with no voltage getting through. 
Any ideas? 

EdTheHeaterMan

There are several safety and limit controls between the S8610U and the transformer. One of those components is the cause. A process of elimination is needed to pin point which one. This is electricity. and not just regular electrician house wiring electricity. This is control wiring. Not everyone in the Plumbing, HVAC and Electrical trade has the aptitude or experience to find your problem.

Can you offer the model number of the boiler or furnace or post a photo of the wiring diagram? With that I can look for possible places to start.

EdTheHeaterMan

Van, I realize you are probably not at the customer's home. So, getting the info then returning to the home or office with the answer does not accomplish what you need.

Here is a wiring diagram from another post that is having a boiler problem. I have added some nice colored lines to illustrate the path of the electricity. 24V starts and ends at the transformer. that transformer may be inside a control or may be attached to a panel inside the front cover. Regardless, if you can identify where the 24V transformer starts and finishes, then you can follow the path of the electricity.

In this case the 24V transformer is inside a Honeywell aquastat L8148. The starting point is illustrated in RED. The first connection is the Z terminal. It ends at the TV terminal in blue. With nothing else happening, if there is 120 VAC to the L1 and L2 on the Aquastat, you can measure 24V between Z and TV with a volt meter.

As long as the 24V is on, then you can follow the RED line past the 1K2 relay contacts first green circle(they get pulled in when the thermostat calls for heat). The next green circle is the limit temperature switch. If the boiler is cold, those contacts are also closed (or pulled in).

Follow the RED line to the plug that goes to the automatic vent damper plug. If the damper is operating properly there is a switch that closes when the damper is fully open. third green circle. The RED line continues to the rollout switch Green Circle 4 and the spill switch green circle 5 before completing its journey to the ignition box that you are having trouble with.

Electricity needs a return path. not that different that say the drainage side of plumbing. The return path of the electricity for that ignition control box is the blue line that returns to the other side of the transformer.

With this idea in your head, you may be able to follow the path of the 24V electricity past all the limits and switches. When you are experiencing the problem, you need to place a jumper wire between the two wires that attach to the Roll out switch to see if that gets the system to start. if not then go the the spill switch. if not go to the aquastat and jumper the R and B on the limit switch. As you jump each safety, the one by one, the problem will reveal itself.

I hope this helps.

109A_5

Hello @VanPlumbing,

VanPlumbing said:

I'm having a situation with intermittent voltage getting to a s8610u.

If there is a Honeywell L8148 Aquastat involved the solder joints where the Switching Relay connects to the circuit board may be the intermittent defect. Common problem.

HomerJSmith

See my comment on page 3. https://forum.heatinghelp.com/discussion/190126/boiler-not-firing-happy-thanksgiving#latest

VanPlumbing

Hi there I appreciate the responses. I can trace the 24 all the way to the board but it doesn't get past the board. Reminder, this is a brand new board. Also I doubt it's any safeties tripping because if I bypass and jump the board again then put back the original wire with the safeties (without resetting any of them) to the module it functions properly, which wouldn't be the case if any safeties were tripped. 

VanPlumbing

As far as I can see as well there are only two safeties on this boiler which are the flame rollout and vent flow; both if which would require a manual reset if they tripped 

109A_5

VanPlumbing said:

Reminder, this is a brand new board.

Reminder, wow, we just learned it is a boiler with a new board. Did it have the same problem before the board was changed ? The new board could be bad. Can you give us more of a hint as to what the actual equipment involved is. Control circuits are not that complicated, but if you want a detailed check here, check there, it helps to know what control devices are involved, is there a Damper ?
Are there any loose crimped on wire terminations ? Basically there is a point in the circuit (a connection, switch, control, safety limit, etc.) that has 24 VAC (or most of 24 VAC) across it when it should be zero volts, like a switch being open when it should closed.