Gas and Oil Home Heating Furnaces - Pulsing Thermostat
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puffer
07-20-07, 08:10 AM
I have an old (1988) Jade Controls electronic setback thermostat.
When turn it on for heat it produces a pulsating signal (24V to 4V across thermostat terminals) which I suspect is not what should happen. It is a two wire device so that the thermostat is in series with the gas valve solenoid. Have connected a bypass switch which enables me to bring the room temperature up to 70F then switch over to the thermostat for automatic control.
When on automatic there is still a bit of pulsing for a few seconds but it then settles down to 4V across thermostat (and hence about 20V for gas valve).
Do I need a new thermostat or is there something cheaper I can do.
P.
When turn it on for heat it produces a pulsating signal (24V to 4V across thermostat terminals) which I suspect is not what should happen. It is a two wire device so that the thermostat is in series with the gas valve solenoid. Have connected a bypass switch which enables me to bring the room temperature up to 70F then switch over to the thermostat for automatic control.
When on automatic there is still a bit of pulsing for a few seconds but it then settles down to 4V across thermostat (and hence about 20V for gas valve).
Do I need a new thermostat or is there something cheaper I can do.
P.
mbk3
07-20-07, 11:22 AM
Have seen that several times. Replace t'stat
adamplghtg
07-20-07, 08:07 PM
Have you tried changing the batteries yet?
puffer
07-22-07, 05:47 AM
Yes I did change batteries but thermostat operation is the same.
(the purpose of the batteries is just to remember settings and time during a power failure)
(the purpose of the batteries is just to remember settings and time during a power failure)
Jay11J
07-22-07, 06:33 AM
I agree, replace that t-stat with a new Honeywell T-stat.
adamplghtg
07-25-07, 06:19 AM
The purpose of the batteries in a electronic thermostat is to remember the settings AND to tell the furnace when to come on. Sometimes when the batteries are weak, it will send a weak or pulsing singal to the thermostat, which will make it very confused and act funny.
Like the other two said, change the thermostat.
Like the other two said, change the thermostat.