Venter switch problem.

[modesco666]

I dug further into my furnace ignition timing out and found that the venter pressure switch has a buildup of oxidization on the contact. I wiggled the wire and the igniter then lit. I decided to bypass it to get my hous warm again. Then I cleaned the electrical contact. Does this corrosion indicat a problem wth the switch?


BTW thanks Richard for your response. I would have probably tried a new ignition controller next $$$$$$!

[rabadger]

Turn the unit off do not run it. Change the switch. Install new one. When you took it apart you screwed it up. That switch is a safety device. It must prove draft before the unit can light. How do you know it's not the venter?, the flue? NEVER, NEVER, NEVER jump a safety device. That's a great way to cause not waking up in the morning.

[modesco666]

I only jumped it to see if it would ignite and it did. It seems not to ignite consistantly. I think my igniter is gone. ANy way to check it?

[rabadger]

I think my igniter is gone. ANy way to check it?

Nope. Several things have to happen in order for the flame to light. For some reason it is not always happening. You say first the stat, then the pressure switch, now the spark. You started at the beginning of the process jumped to the end and left everything in the middle out.

You need the tools to test for resistance, voltage, draft, amps, gas pressure, and temperature. Have it serviced.

[modesco666]

Thanks Richard for all your help. I definately have a defective ceramic ignitor and maybe the controller itself. I check all voltages to the unit and check the pressure switch and it was activating. I traced the wiring from the igniter to the controller and to the power supply. I noticed that the hot wire is wired throught the controller which I assume has a relay to active the igniter after 30 secs. I disconnected the connection at the controller and jumpered the wires with a piece of house wiring. I turned the system on and checked to see if the ignitor lit. It didn't. I then disconnected the igniter and connected my multimeter to the connectors and turned the system back on and there was 120v. So at least i know for sure that the ignitor doesnt work.

I'll post back when I figure it out or at least when my furnace guy comes next week. I did order an igniter from him and I'll pick it up tommorrow. I had also ordered an updated controller off ebay. I hope to get that by Friday. My controller is over 10 years old. M y furnace guy did say it might need to be replaced soon.


Sorry about the multiple threads.

Thanks, Chris

[rabadger]

Look at the clear plastic tubing connected to the pressure switch. If you have condensation in the tubes it can cause the type of erratic lock out you are talking about.

How old is the equipment, make, model? 80%, 90%.

Contact the factory tech service department for the correct glow bar check out steps.

[modesco666]

Thanks again Richard for your help. :D I checked the tubing and there was no condensation but the connector on the pressure switch semed to be a bit black so I cleaned it. I also installed a new igniter and now have heat. It did lockout once so I tapped the pressure switch and the igniter came on and worked again. Maybe I should also replace the pressure switch as a precaution. I'm also wondering how often the furnace should come on and how long for. My thermostat seems to let the temp drop 1 degree celcius and turn on the furnace it runs only about 3-5 mins and shuts off at the set temperature. Is this bad?


To answer your question my furnace is and Olsen Ultramax. Installed proabably in the early 90's maybe. It was converted from propane to natural gas in 94. I have no idea what the efficiancy is. I'm still trying to find that out. If it is 90 or more I can set my thermostat for high efficiancy. I also have a ritetemp thermostat that I can set the temp swing on. I might try and contact Olsen to se if they know what the rating is. My furnace serviceman says that it is a really good furnace.

[modesco666]

This might be a key that it is a 90% or higher. I have a power vent and plastic PVC pipes in and out of the combustion box. It is controlled by a white rogers 50e47-170 controller. I have purchased a new Honeywell controller S8910U1000. It seems to have more features to help troubleshooting the unit.

[modesco666]

I inquired online about the year and efficiency of the model and heres the reply.

"The serial number indicates that the furnace was manufactured as an L.P. Gas-fired furnace on November 2, 1992. The furnace has an A.F.U.E. rating of 92.7%."

It was converted to Nat gas in 94.

It might seem theres a little life in it yet.