Hello everyone,

I have searched this forum extensively and haven't found a solution to my boiler issue, so if my question has already been answered, please link me to it.

I have a Weil-McClain P-CG-5 boiler heater. It was working fine up until a couple days ago when I noticed it was getting rather chilly in the house. I went down in the basement and checked the pilot. It was on. The water circulates through the house but the burner(s) won't fire up to heat the water. I checked the thermostats and they both work fine. there is voltage at the boiler and to the thermostats. The thermostats are calling for heat but the water circulates but doesn't get warm. It is very cold here in Indiana, and I would greatly appreciate any sort of guidance in repairing this issue!

Thanks!!!

Tony

 

I am assuming its a CGa. Is the vent damper open? If not swith the damper from auto to manual.
What does the pressure say on the boiler gauge? (Possible low water cut off).
Check for 24 volts at transformer C and Y.

Start there and verify the model #

Mike NJ

 

Thank you so much for the reply

the full model number reads CG-5-SPDM.

I'm not exactly sure how to read the gauge but here goes.

it reads 16 psi or 40 ft H20 (?) with the red dial at 30 psi.

I'm not sure what you mean by transformer C and Y.

The damper is an automatic and it is closed right now.

Thank you Very Much for you help it is very much appreciated!

Tony

 

in addition to my last post, what is an acceptable reading for the gauges in case of a low water cutoff? If i add water, will the gauge move immediately so i can monitor how much water is going in?

 

The 16 psi is fine. Dont add water. There is a switch on the side of of the damper. Switch it from auto to manual. Let me know what happens.

Mike NJ

 

I just switched the damper from Automatic to "Manual Hold Open" and it didn't open or move at all but i heard a clicking noise.

 

How do you know it did not open? The slot on the side should show vertical. Some times the switch contacts get crud on them. Slide the switch back and forth a couple times then set to manual. Also make sure the wire harness at bot ends for the damper are plugged in firmly. We want to get that to open. If it did not open turn it manually to open with a adjustable wrench. The boiler should fire up. If not we will go to the next step.

see page 50 here for vent damper instructions.
http://www.weil-mclain.com/en/multim...1-009_0107.pdf

Mike NJ

 

The blade was horizontal when i switched it to manual and it didn't move. I moved the blade to the vertical open position and it didn't fire. The i wiggled the contacts and nothing changed. Is there a way to test that with a tester to see if it is getting/sending power? I really do appreciate your help!

 

Yes make sure its vertical. From the picture on page 50 what damper do you have? You have to leave the switch on manual and turn vertical. Or if the green light comes on its vertical. Is the t stat on calling for heat. Because you heard a clicking I am assuming power there.

Ok If not get your volt meter out and start the test procedures on page 51. Open the front panel and you will see the transformer on the left I believe.

You know your skill level and I dont. Remember your working with electricity here.

[and I usually like to say: WARNING! 120VAC INSIDE! YOU CAN BE KILLED! please understand what you are doing! NJT-edit

http://www.weil-mclain.com/en/multim...1-009_0107.pdf

For the heck of it check the switch on the draft hoof. Its small and round and has a little red button. Push that in. Anything?

 

It's the Effikal or Field Damper. I have the Tstat set to 80 to call for heat for sure. there is no red button on the draft hood. I'm going to start the test procedure on pg. 51, but just for my knowledge, what is terminal C and Y before i get started?

 

I found the red button on the hood but it's solid and won't press or depress.

 

C and Y are the terminals on the transformer. You should be getting 24 volts there. Take the front cover off.

You said the pilot is lit correct?

You have the damper on manual and the slot on the other side of the damper motor shows open like in figure 28 page 50?

Mike NJ

 

Yes indeed the pilot is lit. I am not getting any decent voltage on what i see as the transformer. Is there an image you could point me to to verify i'm testing the transformer and the right ones? I was getting .08 volts on what i was testing but that could be my fingers too and i'm not even sure it's the right terminal(s).

My damper does look like the figure 28 on page 50 with the damper blade open.

 

Page 34 figure 23 has the electrical diagram. Y has a black wire and C is a green wire and a blk. Also if you look by the terminals you are measuring there should be the letters there. The circ is running correct?

http://www.weil-mclain.com/en/multim...1-009_0107.pdf

Mike NJ

 

I'm getting 25.6 Volts Across C and Y. i was testing the wrong device. next in the troubleshooting diagram it says to test the gas valve terminals is there a diagram of that also?

 

Two wires going to gas valve. But the next step on page 51 is to test for 24 volts at terminal C and yellow vent damper connecter. You need to unplug the harness going to the vent damper and probe the molex connector with the yellow wire.

Mike NJ

 

OK I think we are getting somewhere now! I'm not getting any voltage between the C and Yellow wire nor anything at the red and black wire on the gas valve.

 

i'm reading and studying the diagram to find out what the spill switch and thermal rollout fuse is. Is the button on the draft hood supposed to be pushed in? it's sticking out kind of far and won't depress...is that an issue?

 

OK you will not get 24 volts at the gas valve if you dont have 24 volts from c to the yellow harness wire going to the damper.

Are you sure you held the test probes firmly and had good contact? If indeed no 24 volts there but 24 volts at the transformer the there is a defective part inbetween these connections.

We need to check the roll out switch for continuity. The one with the red button you pushed on the draft hood. Pull a wire off and set your meter to test continuity. Yes/no?

If yes then put the wire back on there and test the spill switch towards the bottom of the burner. Its ceramic and has two wires going to it. Pull one wire and test for continuity. yes/no?

Next would be the aquastat. Should be past the transformer towards the back and have a grey cover. There should be two wires there. Pull one wire and test for continuity. Yes/no?

Let see what you get.

Mike NJ

Mike NJ

 

Pardon my ignorance here but should i kill all power to the boiler before testing continuity after the transformer?

 

Yes if you like.

Mike NJ

 

OK I get continuity on the aquastat and the roll out switch, however the spill switch is corroded badly and in very very dirty and does not display continuity...

 

is there a way to safely by-pass the spill switch to make sure that is the culprit?

 

ONLY TEMPORARILY! It is permissible... if you don't have continuity at the spill switch, that will definitely stop the main burners from igniting.

I want to know that you have functional CO detectors in the home!

 

OK could you remove the spill switch? I think one or two screws hold it. Pull the wires off, take it out, and test for continuity. Still nothing? Clean up the connections and test again? Nothing?

These are not resettable and trip if flames roll out and means something is wrong. Sometimes its dirty burners because the pilot dont light the burner quick and you get like a mini explosion. For test purposes you can connect the two wires from the roll out switch togrther to see if the boiler fires. But by all means dont run the boiler without this device

YOU REALLY NEED TO LOOK AND IDENTIFY WHY THIS DEVICE FAILED Determine cause and correct condition. Failure to do so will cause severe personal injury, death or substantial property damage.

Let us know.

Mike NJ

 

Mike, the SPILL SWITCH is usually resettable... the ROLLOUT often is not... (sometimes is).

A little more info:

The SPILL SWITCH mounted on the atmospheric vent hood will trip if there is a blockage in the chimney or flue pipe because the exhaust gas will 'spill' out of that vent.

The ROLLOUT SWITCH is mounted down low, by the burners and will trip if there is a blockage in the flue passages inside the boiler... and yes, flames WILL 'roll out' if that happens!

 

Yes Your right. I am going back a few post where he pushed the reset button on the spill switch. I assumed that was good. If its not tripped it may be dirty connections.

Clean all the connections and test again. Connect the two wires together to test but as trooper said do you have CO detecters?


Mike NJ

 

I pulled it completely out and still no continuity. If perhaps there is a mini explosion going on, then when i jumper those two wires together what should i watch for? how can i clean the burners? How often should they be cleaned?

Thank you so very much!!!

 

The spill switch your talking about is the one on the draft hood correct?

Or are you talking about the one down by the burner?

Connect the wires and the boiler should fire up. Then post back here.


Mike NJ

 

You need to answer this question please.

 

I do not currently have CO detectors in the house. I am going to wally world right now to get one.

I connected the wires together and it fired HOWEVER i disconnected it quickly because the flames were coming forward and it smelled like something rubber was burning....

 

Ok where is your boiler? I believe you should have one near the boiler ans one at like the to ceiling of a stairwell? Could something of got in the burners? Take a look. Let us know.

And what switch were you talking about.

this one

510-300-014 - Weil Mclain 510-300-014 - Spill Switch w/ Manual Reset, 240°F for CG, CGA, CGx Boilers

Or this one

512-050-230 - Weil Mclain 512-050-230 - Rollout Thermal Fuse Element, 228°C
Mike NJ

 

the house was literally built in 1849 (farmer says it's been in the family since then...it has log beams and has been updated) and the boiler is in the basement. it's unfinished with a cellar door on the front porch to get to the basement. there aren't 110 plugins in the basement so i'd have to put on above the stairwell and then one in the main part of the house. isn't there supposed to be one on each floor?

There is nothing but lots of rust on the burners. Could that cause the radical flame?

 

Yes. Possibly water damage. Possibly you can remove them and clean them up. But what switch were you refering to just so we are on the same page.

Mike NJ

 

The Roll-out thermal fuse is the one that has no continuity and also the one i bypassed. it fired up but it's not burning right that's for sure.

 

Thank you for being honest...

Shut it down! Do NOT run it! Please don't wake up dead!

I believe CO detectors should be low in the room. CO is heavier than air... I think... you should have one on every floor at least. In each bedroom seems like a good idea to me.

Not only do you need to clean the burners, but the entire boiler needs to be cleaned... this involves getting up inside and brushing out the internal flue passages... and probably involves significant disassembly to get to everything.

If the rollout has tripped, DANGER!

 

I shut off the main power breaker and I moved the gas valve to the off position...that should be as shut down as i can get it shouldn't it? I'll get the switch and clean the burners tomorrow morning

 

See my post #25 below. Please have the boiler professionally serviced.

Yes thats as shut down as you can.

Like Trooper said you may need to disassembly most of the boiler and brush the passage ways between the cast sections. Also if the burners are too bad you may need new ones. Plus find out why there is rust. Rain coming in from the flue? Condensation? Even if you spend the money on repairs or a new boiler you may run into the same issue.

Good luck

Mike NJ

 

Thank you VERY much for your information. If nothing else, I have a greater understanding of how a boiler works. You helped me greatly and hopefully somebody else who reads this thread.

It's looking like I should go ahead and have it serviced before I use it.

Thank you again!!! you are very kind!

 

My apologies NJ TROOPER. Thank you also!