Furnace won't fire (so no heating) please help troubleshooting

Jamie Hall

Before you do anything drastic to the power vent, check and make sure that it is, in fact, getting power. What should happen is that the thermostat -- or aquastat -- should call for the furnace to come on. The Field vent damper should then open. Once the vent damper opens, then the power vent should turn on, and after that the furnace should start. But... if that vent damper doesn't open all the way, or if the switch inside it which tells the rest of the system that it is open is faulty, then... you get what you have. Nothing. And I am deeply suspicious of automatic vent dampers...

Shachar

thanks @Jamie Hall . The last techs that were here (not the ones with the turbo encabulator...) said they tested and the power vent outside was getting 120V (or 110, dont remember) but it still didnt start. The damper did seem to turn all the way to the open position.

pecmsg

Why is there Soot on the front cover, that's part of the combustion process and shouldn't be inside the home.

Been like that for years and none of your service providers said anything?

Shachar

I asked both service techs companies that were here today about this and they all dismissed it as 'that's just soot that leaked from the pipe'. I have no idea how it got there as it was like this 12 year ago and did not change or gotten any worse. I understand the importance or danger if combustion is happening outside the boiler. I'm not sure how to proceed with regard to the soot. I really don't know what happened to make the soot on the front cover. I can try emailing the previous owner if he knows what is it.

JUGHNE

Your power venter is controlled by a relay in the "Field Controls" box near the power switch.
24 volts from maybe the motorized vent damper or the thermostat engages this relay......fan should start......round pressure switch on side senses pressure thru that copper tube in the exhaust and that switch closes to start the burner.

So who ever comes along next should check for 24 volts to the relay. Then 120 volts to the fan motor.

There is a good chance that the fan motor is toast....as it says to oil every year. They have a rough life.

Your water fill valve does look rough and could be due for replacement. While they do that they should check your expansion tank.....if no water comes out of the Schroeder valve
(looks like a tire valve stem under a blue plastic cap) the tank can be recharged to 12-15 PSI of air.

HVACNUT

Regarding the soot, just make sure when all repairs are completed the tech does a combustion test. It's a must.

The draft regulator looks like it has a stopper to prevent the damper from swinging out and theres no Blocked Vent Switch there. That's not correct.

Do you know if the boiler ever used a regular chimney?

mattmia2

The blower wheel and such probably don't have to be replaced but should be all taken apart and cleaned. the tech who does it should then do a combustion analysis to make sure the burner is set properly, it has proper draft and that damper is set properly. That probably wasn't done when it was installed and that is why there is soot. the boiler itself may also need cleaning. the combustion analysis is very important with it being power vented and having the barometric damper.

Shachar

I got the quote from the service techs and it seem to me like they are really over-pricing it so I wanted to ask for some advice.
I looked up the motor part number 46275900 and find it for around $80-$90 on several places like amazon, sears and part sites. I might also be able to buy this at the local supply store. Replacing it seems pretty straight forward https://www.youtube.com/watch?v=wdKUUhctuUw. I also read the instruction manual about removal and installation of new motor and also seems pretty easy.

The feeder I do want to replace as well as do a complete checkup/analysis as people suggested here (as I am not a plumber and don't want to deal with the draining of the system and such)

What do you guys think about replacing the motor myself, seems like some screws and connecting the wires the same way, and sealing. Is there anything else to it?
I can use the service tech for replacing the corroded feeder and doing the checkup/analysis.

Thanks.

Shachar

@HVACNUT The house never had a chimney.
Are you saying there should be a Blocked Vent Switch and it's missing?

mattmia2

Did their quote include cleaning and setting up the combustion? It should have. If it did then there would be a couple hours labor in there for that.

JUGHNE

Where does the gas water heater vent to?

Shachar

@mattmia2 nope. they gave me a quote for the motor replacement (just the motor, not the wheel or the whole assemly) and a quote for the feeder replacement (feeder part I saw costs about $50 - but for replacing feeder I understand there is more labor involved like draining the system etc. They quoted the motor replacement double than what they want for the feeder replacement.

Shachar

@JUGHNE I used to have a water heater that vented to the same pipe. When that old water heater died I got a (super noisy - it was a mistake getting it...) water heater with its own power vent which vents using another hole in the wall. The guy that installed the powervent water heater plugged that pipe extension.

mattmia2

I might be inclined to call them and ask what it would cost to replace the motor, clean and adjust the boiler, and replace the pressure reducing valve all in one quote. I really don't have enough information to tell if their quote is fair but there are costs of running the business they have to cover that someone just selling you the motor doesn't.

Jamie Hall

@Shachar -- please do yourself (and us) a favour and get a technician in there who actually will go through your system and find the things which are amiss and fix them. No, it won't be free. No, it won't be do it yourself. But... it throwing parts at your problem or making supposition just isn't going to work.

A competent technician could, I dare say, have your system running as well as it can in a matter of hours, though he or she might have to make two visits if there are actually parts which need replacement.

Have you checked "find a contractor" for your area? Where, exactly, is this project?

pecmsg

If you insist on doing this yourself Invest in a "Low Level CO Detectors. Not the UL Approved type the big box stores sell but Low Level. They will probably save your life!

SuperTech

> @Shachar said:
> (Image)

Sounds like my guess was correct earlier in the thread. That Power vent motor hasn't been properly cleaned and oiled in years.

I always do a complete combustion analysis whenever I replace a power vent motor. The power vent assembly has a damper that needs to be sent properly for the required overfire draft.

Shachar

@SuperTech Yes, it does seem to be what you suspected

unclejohn

Replace that, what for couple drops of oil and she's good for another 15 years. But seriously I would move that vent damper up as far as the wiring will reach and get rid of the damper.

Shachar

Update: got another quote from the same service tech guys that were here. They don't replace just the motor but instead the motor assembly with the wheel as well. The quote includes the motor+wheel replacement and checking and cleaning the vent, feeder replacement and a complete system check with combustion/draft test and adjustments. Not sure if thermocouple is needed or included (as the pilot went off by itself initially (although it doesn't turn off by itself now) so not sure why it went out. It's not cheap but I guess it has to be done...I thought about replacing the motor myself as it seems pretty simple, but I'll just pay for it.

SuperTech

Just don't forget to remind the service tech to clean the motor and oil it with six drops of SWG super lube every year as part of the annual maintenance.

Solid_Fuel_Man

I would "strongly" consider replacement of the boiler with a sealed combustion unit. These are made to vent without a chimney, and do not rely on indoor air for combustion. The house is likely in a slight vacuum where the boiler is located, this will pull all sorts of nasties into the basement through the boiler venting when the draught fan isnt running.

As others have said, the soot on the front of the unit and all over the vent pipe are telling. That barometric damper is needed per the power vent (drought fan) kit.