GE Gas Furnace problem - doesn't automatically kick in


  #1  
Old 03-29-09, 02:59 PM
L
Member
Thread Starter
Join Date: Mar 2009
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
GE Gas Furnace problem - doesn't automatically kick in

1. In which area you live and ambient temperatures you usually experience.
Southwest USA, current temps around 50 at night, 70 in the day
2. House style and construction details. single story frame
3. Make, model and age of equipment related to the problem.
GE Gas model (as best as can tell) BLU080E936A0 about 30 years old
4. Fuel type. Gas
5. Water temperature and pressures of boiler systems. NA
6. What type of zoning do you have with your boiler system. NA
7. Thermostat type. simple Honeywell CT31
7. Anything else that would be useful. No detail is to small. The more information you provide the easier it becomes for the professionals in this forum to determined the cause and correction to the problem.


Lightning strike within about a 1/4 mile, after that the previous digital thermostat started acting up, display going blank, etc. This has happened before and I simply replaced with the same type thermostat due to convenience and everything was fine.

This time I played around with the digital thermostat and could get the display going by cycling power for a period of time, but the furnace would light up and would not automatically kick the fan in, but turning the manual fan switch would cause hot air to blow and the furnace would apparently stay on until fan was manually switched off. If the manual fan switch is not turned on shortly after the furnace kicks in, the furnace will shut itself off.

Thought it might be a thermostat problem and had wanted to switch to a simpler thermostat less susceptible to power glitches anyway so bought the CT31 and installed it. Same problem with the system. Looked at the schematic for the system and noticed that there are fusible links in the system (susceptible to power glitches?)

Any pointers/suggestions?

lepton
 

Last edited by lepton; 03-29-09 at 03:19 PM.
  #2  
Old 03-29-09, 04:07 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
Fusable links

If you can find the links check them with an ohm meter. If the link is burned out the meter will show open a good link will have very little resistence.
 
  #3  
Old 03-29-09, 05:42 PM
L
Member
Thread Starter
Join Date: Mar 2009
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
ok

fusible links ohmed out ok

lepton
 

Last edited by lepton; 03-29-09 at 07:57 PM.
  #4  
Old 03-29-09, 05:53 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
Fan problem

Just re-read your original post. If the fan will not come on without setting the stat to "fan on" you most likely have a bad fan relay. This relay may be part of the furnace control circuit board if it has one. The fan may also be controled by a thermal switch. If you can get a good photo of the schematic you can post it on photobucket.com or similar site & provide a link here.
 
  #5  
Old 03-29-09, 08:25 PM
L
Member
Thread Starter
Join Date: Mar 2009
Location: USA
Posts: 3
Upvotes: 0
Received 0 Upvotes on 0 Posts
eureka

Originally Posted by Grady
Just re-read your original post. If the fan will not come on without setting the stat to "fan on" you most likely have a bad fan relay. This relay may be part of the furnace control circuit board if it has one. The fan may also be controled by a thermal switch. If you can get a good photo of the schematic you can post it on photobucket.com or similar site & provide a link here.

It has a thermal fan switch. That must be it, it's in a combined unit with a fusible link. Probably will be hard to find around here. Thanks for the pointers. I will try to get a photo of the schematic to post for others to be able to use later.

lepton
 
  #6  
Old 03-30-09, 03:37 AM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 12,682
Received 41 Upvotes on 39 Posts
Another Possibility

Usually there are different speeds for "heat" & "fan on". Maybe the heating speed of the fan motor is bad. You could check to see if you are getting power to the fan motor.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: