Anyone else having problems........

mtfallsmikey

We lost 1 phase to both of my buildings 2 weeks ago, and caused my EMS to go beserk. The Building Control Unit clock would not syncronize with the workstation clock, lighting contols would not work, etc. When I got out of residential work 8 yrs. ago, I was seeing a lot of weird stuff happen with W/R programmable stats like the ones you describe.

Steve Ebels_3

Stat problems

I'm wondering if anyone else has experienced problems, wierd problems, with power stealing stats. What I'm refering to specifically is on F/A systems that use an integrated fan/burner control. We used several different types and a couple brands of these stats and have had numerous no heat calls which were remedied by replacing the stat.
I've found that the common symptom is erratic behavior of the furnace. They will go through the ignition cycle to varying degrees and then fail. Sometimes the inducer runs its normal length of time and the ignitor relay doesn't pull in. Sometimes the inducer wil just sit there and start/stop start/stop over and over. Like someone is sitting there making and breaking the stat connection.
In a couple of cases we replaced the board because that's what it acted like only to be called back in a couple weeks with the same complaint. Re-installing the old board and changing the stat is what cured those. Same with the other wierd stuff, change the stat to a battery or mechanical type and no mo problemo.

Am I mis-applying these thermostats? Are they not supposed to be used on certain types of appliances?

Darrell

stupid controls

> I'm wondering if anyone else has experienced

> problems, wierd problems, with power stealing

> stats. What I'm refering to specifically is on

> F/A systems that use an integrated fan/burner

> control. We used several different types and a

> couple brands of these stats and have had

> numerous no heat calls which were remedied by

> replacing the stat. I've found that the common

> symptom is erratic behavior of the furnace. They

> will go through the ignition cycle to varying

> degrees and then fail. Sometimes the inducer runs

> its normal length of time and the ignitor relay

> doesn't pull in. Sometimes the inducer wil just

> sit there and start/stop start/stop over and

> over. Like someone is sitting there making and

> breaking the stat connection. In a couple of

> cases we replaced the board because that's what

> it acted like only to be called back in a couple

> weeks with the same complaint. Re-installing the

> old board and changing the stat is what cured

> those. Same with the other wierd stuff, change

> the stat to a battery or mechanical type and no

> mo problemo.

>

> Am I mis-applying these

> thermostats? Are they not supposed to be used on

> certain types of appliances?

Darrell

stupid controls

I believe the technical term is the control got stupid! Seriously, when I go on a call with erratic symptoms, the first thing I do is check primary AND secondary polarity. Then I check for a good ground. Then I change the stats to simple mercury bulb stats with anticipators and almost every time the symptoms go away. I do not know why. It's almost like the t-stat is too good for the real world environment and demands of a home. And I find the same thing to be true whether it is F/A, BB, Radiant, Fan Coil, or whatever. I'm also not above wiring a tempstat temporarily and tucking it in behind the real t-stat to eliminate the owner second guessing me.

Empire_2

Micro processor based t-stats.

Often times the micro and the solid state circuit boards on the furnace interfere with the t-stat itself. Try this: Add isolation relay on your heat/ cool and fan circuits. it's a pain, but should at least answer you Q: as to why this happens.

Mike T.

Tony_23

Power stealing

I quit using them. It's either battery or 24 volt, now. I always run at least 5 wire to stats anyway, so it's not a problem having the common terminal connected.

Glenn Harrison_2

Hate to break it to ya...

but this has been a problem since the late '80s. Carrier for example mandated in the intallation manuals that either a battery operated t-stat or an isolation relay wired thru the "W" circuit must be used, because any voltage sensed at any terminals, but "W" especially, would cause erratic problems when using powerstealing thermostats. That's why I love the new Focus Pro's and Vision Pro's from Honeywell, either battery operated or hardwired ("R" and "C"). Hardware store thermostats are the biggest culprit, IMO.

Paul Fredricks_3

We have found that some of the manufacturers that are using fan boards have specifically said not to use a T89 stat. We found this when we ran into operating difficulties. Don't know if this is the same thing as you are experiencing or not.

BillW@honeywell

VisonPro, FocusPro

NONE of the above are power stealing, just battery or hard wire. None of them require a resistor for use with "green" zone valve or the R8184G oil primary. The ONLY power stealing stat still in our offering is the digital round T8775. You shouldn't have any compatibility issues with the Vison/FocusPro stats, and if you do, please let me know, or call 1-800-468-1502.

Dave Yates (GrandPAH)_1

No issues

here Bill & our customers love the big screen.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Empire_2

I think this Sucks!!!!!!!!!!!!!!!!

It would be real nice if people would answer in order so the conversation makes sense!!!!!!!!!!!!!!!!! I quit!!!

Mike T.

Notice I didn't post at the front??????????????????????????????????????????????????????????? of the line...........

Empire_2

Appology........:-(

Sorry Steve...;-) I know this does not make sense until you get to the BOTTOM.........;-)

Mike T. Boy,....am I in for a beating...;-)

Floyd

Huh?????

You get out of the wrong side of the bed this morning???

Floyd

Love the Vison pros....

Only issue that I have had was that with remote sensors for some reason the temp. is off by about 10 degrees... haven't figures it out, and no the sensor wasn't the averaging one.
It works fine, just ten degrees low. Has happen twice now....

Floyd

Empire_2

Floyd.......;-)

"I Do believe that I did get up on the wrong side today".........;-) Like I said, I am sorry.......;-(

Mike T. Sometimes the stress is overwhelming and I do not think before I react........

Floyd

I know the feelimg....

Hope you know it was just in jest....:-)

Floyd

rucomfy_2

Power stealing stats..

usually will cause issues with the micro-porocessor because of the current being consumed by the stat is being regarded at a call for heat until the relay pulls in.
Some suggestions:

1- Hard wired thermostats that use a dedicated common from the board (24V-C) at the terminal strip, normally pull at least 5-wire to the stat location

2- Battery powered thermostats that are completely independent of the board power supply

3- Isolation relay to act as an interface between the stat and the IFC board. A SPST relay at the terminal strip will work. IFC Board: 24V-R to one side of NO contact W-at board other side of NO contact. 24V Coil- one side to common other side to W from thermostat. Call for heat will energize relay coil and close dry contacts between R-W initiating call for heat. The IFC Board never "sees" the t-stat. An enclosed relay is preferred since it is quieter than a standard open relay.
This option may work best when the unit is already installed or pulling extra conductors is not feasible.

4. Some anticpators will not fuction properly with the low current draw of a micro-processor based IFC. Rheem advocated the use of a resistor between W-C to alleviate this condition. They also said it may help the solve the low current draw that causes erratic operation like the T8600 HW. Rheem Technical Publication Low Profile Gas Furnace #OLCSM-011-04 Rev PS02-98. The local Rheem Distributor may be able get you a copy or two, an excellant resource for this product.

Thanks to Uncle Wayne and Uncle Ted and many other generous teachers who have shared their knowledge.

"The only way to beat it... is to know it." I now own the the knowledge. Thanks Uncle Wayne. Hope this helps you.

Tony_23

FP 5000 feature

Just took delivery of about a month's worth of these.

Happy to find the new parameter # 28. Max setpoint. Excellent feature