Hello All,

I am looking for help installing an R7284U primary oil furnace control. The previous controller was a Phelon all in one ignitor control. I purchased the R7284U and a separate Beckett ignitor. I installed everything as read in this feed. My issue is once I energized it the furnace fired right up, however it never shut down once there was no longer a call for heat. I did wire the incoming hot and red limit together. My furnace is forced hot air I do not have an aquastat. There are only two wires running down to burner, a hot and a neutral. My thermostat is digital and only two wires red/white. They connected directly from the thermostat to the previous primary and I wired them the same way on the R7284U. The hot and neutral to the burner come out of a 4x4 junction box that has some sort of transformer and relay thing mounted to it. There is also a Honeywell fan limit switch mounted higher up on furnace. My question is what shuts the controller down once there isn't a call for heat? Something obviously isn't working right.

Please help I had to take it all back off and put old primary back on with a sticking relay cause it's too damn cold in Maine to not have a furnace. Thanks in adnance for any help.

 

The R7284 U & P should always have 120 VAC live to L1 hot and L2 ground. The R7284 cycle is started putting 120 V hot on the Red limit wire. It goes through multi step start up process unlike older controls which simply use L1 for on off control.

The fix for your problem is to connect the 120 V from thermostat to the Red /limit and see that L1 is always hot via the Safety Wall Switch.

You then get other R7284 U & P features with power always on. The display will show current status. Typically "Standby" when no call for heat. No display means no power! etc. You can also step through History.

Another feature is alarm contacts which close upon failure/lockout. I connected a small battery powered buzzer that sounds upon lockout. Instead of waking up to a cold house it gives immediate notice of burner failure and also power outages.

Then there is a feature called burner off delay or post purge. When the call for heat/limit ends it keeps the blower running for a short (selected) time to purge the furnace of exhaust fumes. If burner is in a occupied space that makes for a cleaner, healthier environment. A real benefit to people with respiratory issues.

 

I have a forced hot air oil furnace and updated to a r7284u primary. L1 and limit wired together. L2 wired to motor, ignitor neutral wire. Blue ignitor wire to blue spade, orange spade connected to black wire to motor. I have a digital 2 wire thermostat hooked to T-T terminals on new controller, thermostat wires do not come from a 24volt transformer they run directly from thermostat to controller. When emergency cutoff switch is turned on new controller turns on and fires furnace without issue. However when there is no longer a call for heat furnace doesn't turn off. The old primary was a Phelon primary which I believe had a limit built into it. What needs to be corrected so when there is no longer a call for heat the furnace will turn off??? Thanks for any help.


separated from... http://www.doityourself.com/forum/bo...84-wiring.html

 

Welcome to the forums.

You posted in two different threads in the boiler forum. It's hard to follow one one problem in multiple threads with multiple other problems.

So you're here now. I'll look into this for you and others will also stop by.

 

Thank you Doughess, the problem with your explanation is the two thermostat wires R/W come directly from the thermostat, there is no 120v involved. The thermostat is a Lux digital thermostat and is only operated by two AA batteries. This is my dilemma obviously the TT wires on the new control do not have a relay that switches 120v on to run burner when there is a call for heat or no call for heat. The current wiring powers the primary constantly and gives me all the fuctions of new controller the furnace just doesn't turn off once call for heat is satisfied.

 

https://www.google.com/search?q=hook...ev3W-YuN0qM%3A

This is an image of fan center on my furnace, there is also a fan limit switch. Out of this fan center only one black (hot) and white (neutral) wire run to burner. The thermostat is not wired to this fan center, nor was it with old primary. So I wired two thermostat wires directly to r7284u as it was on old primary. Hope this helps some.

 

Yes connecting thermostat to TT terminals on R7284 controller will work. It is easy to use a 24VAC relay to provide 120 VAC to red limit. My call for heat comes from a 24 v outdoor reset and I use a relay to activate controller to be code compliant. Actually most thermostat relays will handle 3 amps. The red limit only draws .150 amps.

 

So you are just saying use a 24v relay hooked directly to thermostat wires to supply 120v to limit switch? Then just use a jumper wire on T-T terminals on controller?

 

That 7284 control needs to be programmed for 'furnace' mode and configure the 't-t' option accordingly. I've had that happen to me when i didnt set the control properly, as it is now, internally 't-t' is jumped. I'd tell ya how to program the control but I would really prefer you read the instructions to get acquainted with that fine control....that way you'll know how to set pre and post purge setting as well.

 

hi guys -

Wellspd it seems there is an L7284 menu option to ignore the “TT terminals”. It looks like you may accidentally have that option turned ON. That is, you can turn ON an internal TT jumper and thus the T-T from a thermostat will be ignored and will default to always ON. That seems (to me anyway) like that’s what is happening in your case.

I could be wrong but maybe you can check that out.

I just saw the post from ctoilman ... don't know why there is such a big time difference. I thought I just checked for other posts a minute ago! You lose track when you get old LOL!!

 

There was a menu for thermostat. It said (t-t configured on) yes or no. I said yes assuming this meant i wanted to use a thermostat. If that is correct then my problem is still the same. What creates the function of turning heat on when thermostat calls for heat on the R7284u? Is there a relay which then energizes the limit wire which subsequently energizes the L1 hence starting the burner?

 

Wellspd –

My bad!! I think you are correct if you selected the “YES” option when you are using the thermostat for control. The information (which I guess you already have) is on page 7 of this manual:

https://customer.honeywell.com/resou...69-2467EFS.pdf

So I see what you are saying, it still doesn’t explain why it doesn’t turn OFF.

If you look at troubleshooting on page 10 “Burner does not stop ..” it also suggests checking for 24 VAC across the TT terminals on the control. If you don’t get 24VAC across TT when there is no call for heat then that would mean the contacts are stuck closed.

Is there any way the thermostat wires are shorted together somehow? I think that would do it.


I wonder if the Wiring Diagram on page 2 of this link describes your previous setup. Looks like it may:

http://www.butkus.org/information/sl...k-1_burner.pdf

 

I am wondering if my thermostat does not put out the correct voltage to function with the new controller. This is the link for it http://luxproducts.com/IMG/pdf/tx9600ts_manual_en.pdf My thermostat is only operated by two AA batteries. There is no transformer between it and the T-T connections. So the Red and White wires go straight from thermostat to T-T connections.

 

Wellspd –

I believe the 24 VAC comes from the R7284 itself. This is on the first page of the R7284 manual which indicates basically the thermostat is expected to do nothing more than make a connection between 2 wires (I highlighted in red) which I think most thermostats do. That’s why the statement says it will work also with plain old mechanical thermostats.



When you turn on power do you see the display on the R7284 go through the normal steps seen on page 6 of the manual, with the R7284 then stuck with "RUNNING" on the display?

Do you have the red wire connected to RH on the thermostat and the white wire connected to W1?

I can’t find it in your thermostat manual, but I’m sure there should be something on the display when the thermostat is calling for heat. Did you make sure that is not displayed when the system won’t stop running which would verify the thermostat is NOT calling for heat?

Just found it on page 21:

 

Yes when I put power to the controller it boots up then goes to standby for a moment and then fires burner. The thermostat does show the flashing flame when there is a call for heat. Once the call for heat is no longer the flame symbol on thermostat goes solid. When I had r7284u on and the temperature reached the set point you could hear the thermostat click, however the burner did not shut off. Thermostat wiring- white is set to W1. Red is set to RH which has a jumper to RC.

 

Here is a link to basically what I am replacing however rather than it being made by Carlin mine says Phelon so I am guessing they got bought out by Carlin. Patriot Supply - CARLIN Products

 

Since you are not using the EnviraCOM it doesn’t seem like you would need to do this as ctoilman suggests:

– but maybe it wouldn’t hurt and maybe ctoilman is correct and it has to be done whether or not you are using EnviraCOM.

Nothing seems to make sense here….unless (just groping here) is there some way L1 is connected to the motor and the igniter before it is connected to the R7284? In other words L1 might be connected to the R7284 but it is also connected to the motor and igniter directly – like maybe in a junction box?
 

 

I had selected "furnace" in the settings. L1 and Limit connected to black wire from fan center. All (white) neutrals to L2, connected to (white) from fan center. Orange motor spade from controller to motor Black. Blue controller spade to blue ignitor. No fuel valve. Cad sensor connected to cad terminals. I just don't get it, I know I had everything connected properly as I had researched it before starting. I am beginning to wonder if I just have a faulty controller. Because wired as above it should work.

 

Wellspd-

Well I’m sure no expert but I think I understand how you wired things up, including spade colors and everything, and how your previous setup works (I guess still your current setup since you dropped back).

I don’t see why the control doesn’t turn off the motor and igniter. It’s almost as if the internal TT jumper is ON - yet you have it OFF according to the manual. It can’t be something crazy with the thermostat since it is working with your old control.

Maybe it just is just a bad control. If you install it again I would check for the 24VAC across TT when there is no call for heat as they suggest.

I can see why you are mystified – seems pretty simple and it seems (to me anyway, LOL) you did everything right.

 

Put a volt meter on the red limit wire. Controller should start when it has 120 volts and TT is set on or shorted. If burner runs without 120 volts on red or when red is disconnected then controller is bad.

The function of Red is limit/start. TT function is to disable the controller when open for whatever reason. I use TT after a call for heat to keep burner off until electric stack damper open switch closes connecting TT.

If your thermostat or what ever is calling for heat uses semiconductors rather than relay contacts for 120 volts it may not shut off.

That is one quirk of R7284 red limit circuit, is must be zero volts to deactivate. Do not use a solid state relay to activate it. SSR's never completely shut off. I learned that the hard way trying to use a PID controller SSR output to switch red limit on and off. Had to use a relay to connect and remove 120 volts from red.

 

I don't recall what the menu setting is for 'T-T configured, on or off', but re-configure it the other way than what it is now and see how it works. Ya know, I can grab a 7284U off my service vehicle and check how it should be configured but that would be too easy . Reconfigure it and lemme know how ya make out.

 

Not lying LOL, I was going to suggest that myself when I saw these three different variations of description of that same T-T parameter. But I finally concluded that I guess there really wasn’t any contradiction at all. But still – it looks like Honeywell was having some trouble in that area, although maybe just in clarification:

From page 7 of https://customer.honeywell.com/resou...0s/69-2467.pdf
From page 7 of https://customer.honeywell.com/resou...69-2467EFS.pdf

This is from a training module:



IMHO they are about as awkward and clumsy as you can get when trying to describe this parameter. I think they should have just kept their mouth shut about an “internal jumper” – it seems to me it is totally unnecessary and only confuses the issue.

Maybe do something like this:

... but I guess they would say if you don't mention the "internal jumper" that is also confusing. Who knows LOL!

 

Maybe the more knowledgeable folks can figure this out but it seems to me that the R7284 manual sort of (LOL) implies that if you are using the T-T terminals to control the R8724, then you should NOT have LIMIT connected. That is, LIMIT should be OFF.

So either you use the T-T terminals to control the R8724 and have LIMIT disconnected, or you use LIMIT to control the R8724 and have the T-T terminals jumpered.

Maybe I’m reading it wrong but if you look at Troubleshooting and “Burner will not stop when call for heat ends”, it seems to imply that if the LIMIT contacts remain closed – the burner will just keep running. It doesn’t differentiate between the case where you are actually using the T-T terminals to control the burner and the case where you use the LIMIT to control the burner.

In other words, it seems to imply that if you have a steady power source connected to LIMIT, regardless of whether or not you are using the thermostat for control, the burner will never shut off – and that’s what is happening here, as Wellspd says :

From manual:

I guess there are other ways to read that section, but it seems to me without being real picky, you would have to assume LIMIT takes precedence.

link to manual

https://customer.honeywell.com/resou...0s/69-2467.pdf

diagrams on pages 4-5, Troubleshooting page 10

of https://customer.honeywell.com/resou...69-2467EFS.pdf

 

Until I could figure it out I put old primary back on and figured I had a faulty r7284 and sent it back for replacement. The new on arrives this week so I will try it without limit wire and just T-T connected. My question is how does the thermostat put out 24v if it only has 2 AA batteries and does not connect to any transformer?

 

Wellspd –

I’m no expert for sure, but I believe the 24VAC comes from the R7284 itself. The batteries in the thermostat just power a circuit(s) that is independent of the 24VAC circuit, that is, the batteries power the thermostat display and allows the thermostat to be programmed, etc.

The link below is not the R7284 but it is an example of an oil burner primary control and I think if you look at figure 2 you can see what I mean. The funny squiggly things down in the right hand corner of the block depicting the R8184G, represent a transformer which converts the 120VAC to 24VAC. You can see the thermostat and CAD cell connected to the 24VAC side. The thermostat and CAD cell just make connections based on “decisions” thus completing the circuit. They don’t need to supply power.



https://customer.honeywell.com/resou...0s/69-0429.pdf

I was hoping one of the HVAC guys might weigh in but it looks to me that for the R7284 as long as LIMIT is ON, the burner will run – because of what they say in that troubleshooting section. The way it is laid out in that troubleshooting section it doesn’t seem to be conditional, like it has anything to do with how you have the control set up for T-T. It sure seems like they are saying if your burner won’t shut off, make sure the LIMIT contacts are open.

To me that means you better keep LIMIT OFF if you want to use the thermostat to control the burner. But to me that would then mean the control would have to ignore LIMIT=OFF and would in fact turn the burner ON if the thermostat= HEAT ON, however, the control would NOT ignore LIMIT=ON and accordingly keep the burner OFF if thermostat=HEAT OFF, but instead would always turn burner ON if LIMIT=ON. Seems goofy to me, but to me that’s the implication of that troubleshooting section. An HVAC guy might see the sense of it right away.

I guess if your new control works then what I’m saying is wrong. But if you still have the same problem I don’t see how it would hurt to disconnect LIMIT and see what happens.

p.s. I forgot to say I believe your black wire coming to the burner is coming from some fan control/limit, so if that is what is connected to L1 on the control, it seems to me you would be OK in terms of shutting down the burner when the real limit requires that. But … an HVAC guy could confirm that.