Wiring Diagram

STvex

Hi, I have a Weil McClain Cg15 gas hot water boiler. Is there a weil or even a generic mapping that shows where all the wiring gets connected. I am trying to trace the electricity circle from thermostat-zone value-damper-circulator-gas valve-high limit aquastat-roll out and limit switches, electronic control module and so far. Would like to troubleshot if there is a part not working. Thanks in advance.

Big Ed_4

The zone valves would be one circuit with a switches to turn on the boiler . The boiler would be on the other circuit . Depend on the boiler control ? If a relay the controls the boiler . The circulator and stack damper will open and switch the series circuit to the gas valve . If a spark or igniter controls the boiler the damper (maybe) , safety's and burner would all lead back to the control .

STvex

Big Ed_4 said:

The zone valves would be one circuit with a switches to turn on the boiler . The boiler would be on the other circuit . Depend on the boiler control ? If a relay the controls the boiler . The circulator and stack damper will open and switch the series circuit to the gas valve . If a spark or igniter controls the boiler the damper (maybe) , safety's and burner would all lead back to the control .

Thank you. I have the relay and transformer in one, electronic ignition-honeywell. Would the electrical path follow this way:

1) Thermostat Calls for heat (red and white wire connect)
2) Zone Value Opens (Two red and Two Yellow Wires, connect to?)
3) Damper Opens Up
4) Zone Value turns on circulator and boiler
5) Electricity Goes Through Flame Roll Out and Flue Sensor
6) Gas Valve Turns On after passing through low water cut off safety
7) Aquastat Shuts off burner once receiving desired temperature
8) Thermostat shuts of heat once temperature is reached

I am I missing a step and is this the right pathway? Also, the circulator and electronic igniter are the only 120V feed while everything else is 24V?

Thanks.

EdTheHeaterMan

Can you take pictures form far enough back to see the location of the zone valves, any transformers that are not oroginal to the boiler and the boiler controls? several angles. and close up of the controls.

Sequence of operation
1. thermostat calls for heat to a zone valve
2. zone valve motor opens valve and activated an end switch
3. end switch operates the T T wires or terminals of the boiler. this acts as the call for heat to the boiler
4. vent damper is activated first to open
5. vent damper end switch contacts make once the damper is full open
6. end switch from damper sends electricity to the ignition control and the circulator relay.
7. ignitor activates to light fuel
8. gas valve opens
9. flame is established and the ignition control flame sensor proves there is a flame
10. burner operates until call for heat is satisfied or the high limit temperature is reached
11. high limit will stop burner but the circulator will continue to send that heat to the radiators.
12. water temperature drops and the high limit contacts make and the burner cycle 7. thru 11. above.
13. call for heat is satisfied. zone valve closes and end switch contacts open
14. when ZV end switch opens the vent damper looses bower to the open contacts and will close the damper
15. as soon as damper starts to close the damper end switch opens and the ignition control looses power
16. when the ignition control looses power the gas valve closes and the flame is extinguished.

Exact sequence of operation may vary from one control to another but the basic idea is still the same.

EdTheHeaterMan

here is a possible wiring diagram that will match the precious description
to be more precise I can make you a diagram for your system when I see the pictures and know which zone valves you have. I can also know the heater model number if you provide the CP number of the boiler.

STvex

EdTheHeaterMan said:

here is a possible wiring diagram that will match the precious description to be more precise I can make you a diagram for your system when I see the pictures and know which zone valves you have. I can also know the heater model number if you provide the CP number of the boiler.

Attached are pics.  Thanks for your help.  The model number is cg-4-spdn, the covered the cp number with a transformer under the power switch box, looks like red white thermostat wire is connected to it.  

JUGHNE

I word I did not see in any of the above language was "relay".

There is a plug in relay above the transformer in you picture.

It looks to be a double pole type, one side starts the 120 vac circulator and the other switches the 24 vac to the sequence for ignition.

It shows in the wiring diagram.

You may have another transformer mounted elsewhere as you have 3 zone valves.

EdTheHeaterMan

I appears that the the transformer that powers the boiler controls also powers your zone valves. Is there another one of these anywhere in the system
There is more that one way to wire the zone valves and get them to work. Essentially they are all the same but the R and the W on the thermostat may be reversed and the Common (C) terminal on the transformer may be reversed for some controls and not reversed for others. Also, there is a Low Water Cut Off (LWCO) included in the photos but I don't know if that is connected or not. You have not provided the picture of how that is wired into the system (with the cover off)

Next, the model number you provided CG-4-SPDN indicates that the boiler was originally equipped with a Standing Pilot, Damper and Natural Gas burner orifices (SPDN). Since your pictures clearly show electronic spark ignition control I will assume that the original system was upgraded after the fact, and therefore can only guess at what changes were made.

These two controls are most likely original. the Transformer/Relay (A1) and the High Limit (A2)


These two controls are new Gas valve (B1) and ignition control (B2)


These two controls are not shown. Damper (No need to see inside the damper, they are all the same and I know what is inside there)(C1) and LWCO (C2)

Here is my best guess:
Diagram to follow:

Steamhead

I recognize the wiring around that ignition module. Your boiler was originally standing-pilot, and was upgraded with a Honeywell Y8610U spark-ignition kit. That's a pretty good upgrade to a boiler that's otherwise in good condition. ISTR Weil-McLain marketed these under their own name for a while.

The kit includes stickers showing the changes made to the boiler. The installer may not have put these on the boiler like they should have.

EdTheHeaterMan

Here is the wiring diagram as best as I can guess
If I am correct, that transformer may be very near, or over the maximum capacity. The original boiler with standing pilot would have a minimal amperage draw for the relay, damper and the gas valve.
Adding 4 zone valves would be getting close to the maximum draw with all 3 zones calling at the same time, but still within acceptable limits. The transformer may operate a little hot to the touch but that is to be expected.

Someone added an electronic ignition and electronic low water cut off . If that LWCO is also operated from the boiler control transformer then there is an additional load along with the new electronic ignition control. Each item is minimal current draw when you look at them individually, but when you add them all up, and operate them all at the same time, you will have a problem with overheating and a possible component failure. If that is the case, I would recommend you replace the transformer with a 50 VA (your current one is a 40 VA) that is equipped with a fuse or circuit breaker.

STvex

EdTheHeaterMan said:

Here is the wiring diagram as best as I can guess
If I am correct, that transformer may be very near, or over the maximum capacity. The original boiler with standing pilot would have a minimal amperage draw for the relay, damper and the gas valve.
Adding 4 zone valves would be getting close to the maximum draw with all 3 zones calling at the same time, but still within acceptable limits. The transformer may operate a little hot to the touch but that is to be expected.

Someone added an electronic ignition and electronic low water cut off . If that LWCO is also operated from the boiler control transformer then there is an additional load along with the new electronic ignition control. Each item is minimal current draw when you look at them individually, but when you add them all up, and operate them all at the same time, you will have a problem with overheating and a possible component failure. If that is the case, I would recommend you replace the transformer with a 50 VA (your current one is a 40 VA) that is equipped with a fuse or circuit breaker.

Thanks so much. I have another transformer under the emergency switch. It has what looks like thermostat wiring, red/white wiring. Can you provide a supply house link for the upgraded transformer and can I swap it out? Will it have the same plug in connectors like my current transformer? Thanks!

EdTheHeaterMan

If you have an additional transformer on the boiler, that transformer is most likely providing power to the zone valves. If that is the case, then the existing transformers are adequate. One 40 VA transformer will handle up to four Honeywell zone valves. The transformer on the boiler control (A1) is more than enough to operate the gas valve, damper, ignition control, LWCO and the circulator relay.

If you can provide the pictures of the LWCO wiring (inside the cover) and the transformer under the emergency switch, I can make you a more accurate diagram.

By the way, Why do you need this diagram? Are you trying to add a thermostat that requires a C terminal?

STvex

EdTheHeaterMan said:

If you have an additional transformer on the boiler, that transformer is most likely providing power to the zone valves. If that is the case, then the existing transformers are adequate. One 40 VA transformer will handle up to four Honeywell zone valves. The transformer on the boiler control (A1) is more than enough to operate the gas valve, damper, ignition control, LWCO and the circulator relay. If you can provide the pictures of the LWCO wiring (inside the cover) and the transformer under the emergency switch, I can make you a more accurate diagram. By the way, Why do you need this diagram? Are you trying to add a thermostat that requires a C terminal?

Attached is the inside of lwco and second transformer.  I am the homeowner I wanted the wiring diagram to get an understanding how my heating system works.