A 5 year old RiteTemp 8030 thermostat started mis-behaving the other
day. It would go into a heat cycle and keep on going until the house
is toasty warm. The only way to stop it is by disconnecting the power
to it (remove the control unit from the wall wiring(or turn off AC
power to the furnace). I bought a similar replacement unit at Home
Depot (newer, model 8030C) and all is working fine now. The question
is: I wonder if anyone here have a schematic for the 8030? I think
that there is probably a power device that turns on an internal relay
that is stuck in the "heat mode" when powered on. Setting the
thermostat switch to off or cool has no effect. This unit uses 2 AA
batteries for alternate power source, but replacing them with new ones
have no effect.

On Jan 3, 4:48*pm, cmdrdata wrote:
A 5 year old RiteTemp 8030 thermostat started mis-behaving the other
day. *It would go into a heat cycle and keep on going until the house
is toasty warm. The only way to stop it is by disconnecting the power
to it (remove the control unit from the wall wiring(or turn off AC
power to the furnace). I bought a similar replacement unit at Home
Depot (newer, model 8030C) and all is working fine now. *The question
is: I wonder if anyone here have a schematic for the 8030? I think
that there is probably a power device that turns on an internal relay
that is stuck in the "heat mode" *when powered on. Setting the
thermostat switch to off or cool has no effect. *This unit uses 2 AA
batteries for alternate power source, but replacing them with new ones
have no effect.

There may be a miniature relay in the unit that has a stuck contact.
The only way to fix it, very temporariiy, is to beat it on a very hard
surface in various orientations until the contact opens. But, it is
likely to fail again in a short time, so just toss it unless you can
find a replacement relay.

On Jan 3, 8:24 pm, "hr(bob) "
wrote:
On Jan 3, 4:48 pm, cmdrdata wrote:

A 5 year old RiteTemp 8030 thermostat started mis-behaving the other
day. It would go into a heat cycle and keep on going until the house
is toasty warm. The only way to stop it is by disconnecting the power
to it (remove the control unit from the wall wiring(or turn off AC
power to the furnace). I bought a similar replacement unit at Home
Depot (newer, model 8030C) and all is working fine now. The question
is: I wonder if anyone here have a schematic for the 8030? I think
that there is probably a power device that turns on an internal relay
that is stuck in the "heat mode" when powered on. Setting the
thermostat switch to off or cool has no effect. This unit uses 2 AA
batteries for alternate power source, but replacing them with new ones
have no effect.

There may be a miniature relay in the unit that has a stuck contact.
The only way to fix it, very temporariiy, is to beat it on a very hard
surface in various orientations until the contact opens. But, it is
likely to fail again in a short time, so just toss it unless you can
find a replacement relay.


I don't think it is the relay (brand name MASSUSE type 4E-2L-3). When
I measured/compared the DPDT contacts with the new one, it was in the
same state while power is off. Don't not easily done with power on.

On Jan 4, 8:28*am, cmdrdata wrote:
On Jan 3, 8:24 pm, "hr(bob) "
wrote:





On Jan 3, 4:48 pm, cmdrdata wrote:

A 5 year old RiteTemp 8030 thermostat started mis-behaving the other
day. *It would go into a heat cycle and keep on going until the house
is toasty warm. The only way to stop it is by disconnecting the power
to it (remove the control unit from the wall wiring(or turn off AC
power to the furnace). I bought a similar replacement unit at Home
Depot (newer, model 8030C) and all is working fine now. *The question
is: I wonder if anyone here have a schematic for the 8030? I think
that there is probably a power device that turns on an internal relay
that is stuck in the "heat mode" *when powered on. Setting the
thermostat switch to off or cool has no effect. *This unit uses 2 AA
batteries for alternate power source, but replacing them with new ones
have no effect.

There may be a miniature relay in the unit that has a stuck contact.
The only way to fix it, very temporariiy, is to beat it on a very hard
surface in various orientations until the contact opens. *But, it is
likely to fail again in a short time, so just toss it unless you can
find a replacement relay.

I don't think it is the relay (brand name MASSUSE type 4E-2L-3). When
I measured/compared the DPDT contacts with the new one, it was in the
same state while power is off. Don't not easily done with power on.- Hide quoted text -

- Show quoted text -

No other suggstions - sorry

On Jan 3, 5:48*pm, cmdrdata wrote:
A 5 year old RiteTemp 8030 thermostat started mis-behaving the other
day. *It would go into a heat cycle and keep on going until the house
is toasty warm. The only way to stop it is by disconnecting the power
to it (remove the control unit from the wall wiring(or turn off AC
power to the furnace). I bought a similar replacement unit at Home
Depot (newer, model 8030C) and all is working fine now. *The question
is: I wonder if anyone here have a schematic for the 8030? I think
that there is probably a power device that turns on an internal relay
that is stuck in the "heat mode" *when powered on. Setting the
thermostat switch to off or cool has no effect. *This unit uses 2 AA
batteries for alternate power source, but replacing them with new ones
have no effect.

Sadly, five years is a long time for some of the more recently made
stats. I would replace it and be done with it.

We are presently using a mid-line (now, top then) RobertShaw automatic
set-back (heat-only) thermostat that is 20 years old. It has "Made in
USA" on it - something that is a rarity now.

Peter Wieck
Wyncote, PA