[Fix'n it]

my furnace has been acting fine since my last thread on it.

but now, its acting up again.

i am getting a code 4, ignition failure. the HSI is working fine, and inducer is running.
when it does not fire up, i shut the furnace off, work the knob on top of the gas valve. return power, then furnace starts up and runs normally, kinda. it runs fine, but it does not fire as quickly as it did. just now, the HSI just started to turn off, was still glowing though, then the burners ignited. the HSI used to stay lit for several seconds after ignition.
after the furnace started running normally, i could here a slight buzzing from the gas valve. i took a handy hammer and gave it some slight taps and the buzzing went away. coincidence perhaps.

what should i do ?
thanx

 

[beenthere]

my furnace has been acting fine since my last thread on it.

but now, its acting up again.

i am getting a code 4, ignition failure. the HSI is working fine, and inducer is running.
when it does not fire up, i shut the furnace off, work the knob on top of the gas valve. return power, then furnace starts up and runs normally, kinda. it runs fine, but it does not fire as quickly as it did. just now, the HSI just started to turn off, was still glowing though, then the burners ignited. the HSI used to stay lit for several seconds after ignition.
after the furnace started running normally, i could here a slight buzzing from the gas valve. i took a handy hammer and gave it some slight taps and the buzzing went away. coincidence perhaps.

what should i do ?

Stop using a hammer of the gas valve. :devil3:

thanx

Pull burners and clean them. Could be that the gas valve is sticking, which would mean time for a new gas valve. Might want to check to see if the valve is getting 24 volts, or 18 volts when its energized. If only 18 volts, problem is with wires, wire connections, or board.

 

[Fix'n it]

its fixed. repluged the 2 terminals on the valve and cleaned the chassis ground(that did not look dirty at all)

 

[WhatRnsdownhill]

there is a product called" corrosion x" come in a 16 oz spray can, works great for electrical connections and is safe for use on them, it cuts through tarnish and rust and help prevents it on contact surfaces..along with loosening up anything thats rusted...it seems to eat away the rust....not magic in a can but works better than most of the rust busters out there..

 

[Fix'n it]

it did it again. i taped on the valve and it instantly clicked on. that was yesterday.
has been working fine since. now, valve hunting.

 

[ben's plumbing]

you should still check to see what voltage you have at valve when its acting up to see if the board is causing the issue, loose wires, or valve. without proper troubleshooting replace parts may not fix your problem:biggrin2:

 

[Fix'n it]

you should still check to see what voltage you have at valve when its acting up to see if the board is causing the issue, loose wires, or valve. without proper troubleshooting replace parts may not fix your problem:biggrin2:

ok, i will.

 

[Fix'n it]

ok. i am getting 18v @ the board and valve (back probing the terminals). and at the pressure switch = terminals to chassis ground.
the transformer says its 24v
i will check the board ground, if i can find it. in the past i have checked the board terminals = looked ok. and i then sprayed them with contact cleaner
i will check output of the transformer.

 

[Fix'n it]

transformer is 26v at the board terminals (disconnected).
boards ground is in a multi connecter and looks ok.

the next time it acts up i will check voltage.

 

[ben's plumbing]

see why its important to troubleshoot and not parts change...as b t said ..check wires , wire connectors, and board.. Iam sure you will find the issue..