Honeywell Digital T-stat

RayH

I replaced an old dial t-stat on a 2 zone oil burner with a Honeywell non-programmable digital t-stat. The customer has the heat set at 64 and it is about that temp in the home. The dial says 85. Dip switches are correct. I replaced the t-stat thinking it was defective and the same thing occurs. It reads 85 but is actually about 64 in the home. Any ideas anyone?

RayH

Honeywell T-stat issues

Steve Minnich

Do I have this right? You have two separate thermostats reading a room temp. of 85* when the actual temp is 64*?

Steve Minnich

If that's right, is there some sort of heat source, light, etc near the stat?

Paul48

If the only thing you had to do, was set the dip-switches, and you have the same problem with both t-stats.....what HAS to be the problem? Just sayin'

RayH

The 2nd floor is fine and not an issue. I replaced the 1st floor unit which is on an interior wall in the living room away from any lights. The boiler does have two zone valves that are working fine with resistors.

ratio

what is the model number of the stat?

Fred

Many of Honeywell T-Stats come with a clear/black thin film over the screen that says 85 degrees on it. It is a scratch protector that you need to peel off. Are you sure that isn't the case here?

Paul48

Call up Honeywell and see if they'll send you one that says 64*.

GW

Put the second floor stat on the 1st fl and see what happens.

sunlight33

Put it in a refrigerator and see if it says 64.

Fred

Guys, I really think it was the printed protective film over the display screen. It does look pretty much like the real display.

ratio

That certainly is the simplest explanation for what would otherwise be a real head-scratcher.

RayH

There is no film. This is a real issue that I will have to call Honeywell

ratio

Let us know what you find out. Many of us use & recommend Honeywell stats, something like this is important to know.

RayH

I have been having an issue with a Honeywell T8775a Digital T-stat. When I spoke Honeywell they told me to make sure they is no lamp near by, plug the hole where the wire comes thru the wall to make sure no heat is hitting the back. ( just an unheated basement below.) Upon doing a voltage test they suggested that adding an additional 24v transformer "might" help the situation. Now, I know that a 24v transformer will work 3 zone valves. With two zone valves and an existing 24v transformer their digital t-stat draws too much power to operate. After four trips to the customers home I finally put on a battery powered digital t-stat for them and all is good. I made NO money on this job and Honeywell will not compensate me for their power draining t-stat issues. They make other good products that I like and use. Guys, DO NOT use Honeywell T8775a Digital T-stats with zone valve! Install a cheap battery powered one and save yourself the headaches. Ray Hurilla Plumbing & Heating Co.

ChrisJ

RayH said:

I have been having an issue with a Honeywell T8775a Digital T-stat. When I spoke Honeywell they told me to make sure they is no lamp near by, plug the hole where the wire comes thru the wall to make sure no heat is hitting the back. ( just an unheated basement below.) Upon doing a voltage test they suggested that adding an additional 24v transformer "might" help the situation. Now, I know that a 24v transformer will work 3 zone valves. With two zone valves and an existing 24v transformer their digital t-stat draws too much power to operate. After four trips to the customers home I finally put on a battery powered digital t-stat for them and all is good. I made NO money on this job and Honeywell will not compensate me for their power draining t-stat issues. They make other good products that I like and use. Guys, DO NOT use Honeywell T8775a Digital T-stats with zone valve! Install a cheap battery powered one and save yourself the headaches. Ray Hurilla Plumbing & Heating Co.

I had considered using the T8775A on a recent project.
I assume this didn't have a common wire?

RayH

just red & white