Lennox G14 Pulse purge fan


  #1  
Old 01-11-03, 08:47 AM
M
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Lennox G14 Pulse purge fan

The purge blower or fan in my g-14 pulse is making a lot of noise,and the furnace is not firing on the first try.It is taking a couple of tries.To get through the weekend,could I tie the 2 wires
on the blower together,and put a jumper wire on the pressure switch in case the purge quits altogether? I am also wondering if this is a Lennox only part,if there is somewhere else I could get a replacement part.Thanks for any advice and suggestions.I really appreciate it.
 
  #2  
Old 01-11-03, 08:58 AM
fjrachel
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Try removing the forced draft blower assembly. Clean and oil. As for parts....Lennox no longer manufactures the Pulse furnace...You can get parts through Lennox, but try Johnston supply first.
Your starting problem sounds more like a spark plug, air or gas flapper problem though, even though the draft blower is noisy.
 
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Old 01-11-03, 03:39 PM
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Replacement

I heard about these furnaces, never actually worked on one. Read about them with times controlled explosions with flappers ect, then people started getting killed from them. Failed heat exchangers I believe...... I could be wrong, I know they were Lennox. Thats why they don't make them anymore I suppose, R&D on the public!
 
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Old 01-11-03, 03:45 PM
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info

My AC book says you will get 5 trials for ignition, this pulses 60-70 times per second, I don't even know if you could call that a pulse, how could you tell??? I think I'd start by changing the spark plug.
 
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Old 01-13-03, 02:40 PM
hvactech
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Thumbs down Pulse furnace

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!NOTE TO ALL!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!Please do not give answers that you are not sure of!!!!!

Mark7 if you tie the 2 wires to the purge blower together you will have a direct short in the 120v circuit in the furnace. DON'T DO THAT!!!!!!!!!!!!

The pulse furnace does not require the purge blower to operate in order for the furnace to fire.

The pressure switches are in a normally closed position so jumpering the switch will only bypass the only thing protecting the furnace from a pluged pipe.

In over 10 years and 1000s of pulse furnaces that I have worked on, I have only changed 2 spark plugs and 1 of those I had to change because I broke it. The spark plug and sensor are self cleaning.

If you have not had a qualified service tech service the furnace in the near past, mostlikely the trouble you have been having is that the air flapper is either dirty or torn. Both easily corrected by a Lennox dealer.

Your should also have the hea exchanger inspected if the unit was made before 1990. That is when Lennox had trouble with the exchangers.
 
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Old 01-14-03, 09:42 PM
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Thanks to all for advice.My unit seems to be working,got through the weekend ok,didnt have to do anything.Will order a new purge,just to be safe.The weather here is pretty cold.I figured that the purge had to run and make the pressure switch,thats why I thought I would jump out the switch if need be.Unit was gone over by an outfit that Lennox hired to check heat exchanger.
They left me a new flapper in case the one in there ever needed changing.It looks ok to me,clean and no tears.I like my pulse.This is the first trouble Ive ever had,and I think its a 1985 unit.Thanks again to all.
 
  #7  
Old 01-15-03, 06:57 PM
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Quality

No doubt,... Lennox is a top Quality built unit. I usually see it in the things the customer never see's like how the side panels are secured to the unit, easy acces, room, is the blower easily removed, can you get to the face of the coil easy, adjusters for the belt, although 90% are DD now. Does the unit have external taps for the gauges, or even better, a sectioned compartment in the case of package units... what does it have in line of safetys, does it have a fan cycle control...I worked on a New Lennox this summer with a bad board, they stood behind the product without a problem, but what I liked was a swinging gasketed door with two locking handles, instead of all the 5/16 screws you typically see, and half are stripped in ten years.
You have already got 17 years....good show. I'm replacing several Carriers now in that vintage, with rusted out heat exchangers. Good luck, stick with what works!
 
 

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