Control 3 Taco SR501's with one Thermostat?

Ddentry

HI

I’m a homeowner (well, the bank owns the home!) but pretty handy with things around the house. Couldn’t find anything close enough in the archive…

I currently have three zones of radiant floor each controlled by three separate thermostats: I’d like to control all of them with a single thermostat. Each zone is controlled by a Taco SR501 switching relay. The single thermostats are cheap Honeywell two-wire, non-programable models.

I’m not sure why the original owner put these in three separate zones in the first place. It’s a large kitchen with each part on it’s own zone and the three t-stats in a line on the same wall. The wife wants them all on together...

I bought a RIBL3C 3 Relay enclosure thinking that I could wire the thermostat to that and then each Taco zone controller to the RIB. However, I’m confused by all of the wires from the RIB. Is the RIB the wrong product to do this?

Will I need to add a transformer for the RIB? Currently each zone controller has it’s own transformer inside but nothing to power the RIB.

Is there some better (not too expensive) option?

Advice? Thanks in advance…

-David

Solid_Fuel_Man

Are all 3 SR501s in the same location? You can use the dry contact output from one (master) to run the next and the dry contacts from that one to run the last. However, you may be able to run all the circulator on just one SR501. Look at the amp ratings. What model circulator?

The dry contact output would be wired to the thermostat input the the next SR501. Master, slave, slave.

Taylor

Ddentry

Thanks for the answer. Yep, all of the circulators (Taco 007-F5) and controllers are in the same location. See photos. It looks like someone (before me) tried to jumper from the top controller to the middle one (brown wire jumped from top to middle) but nothing is connected inside.







Which are the "dry contacts"? (I could go out and Google that if I wasn't too lazy!)

Thanks again

Paul48

Mounting position – Circulator must be mounted with the motor in a horizontal position. It may be mounted
vertically with the motor up, provided that the system pressure is at least 20 psi (138 kPa).

Ddentry

Thanks Paul. They've been like this for 10 years and it's out of the scope of this project to change anything now... I just want to control them all with one thermostat...

Paul48

The dry contacts are the ones marked "NC" and "NO" in the sr 501. I don't see how the one you have pictured is controlling the boiler.

Eric_32

You can move the circulator power wire for all 3 pumps to what ever box you want to control them. Run the 3 off one box. You won't be close to the max amps for the control.

pg 2:
http://s3.supplyhouse.com/product_files/Taco-SR-501-4-Brochure.pdf

1/3 hp max 6 Amps....

3- pumps at .71 amps totals 2.13 amps

terminals labeled 4 and 6 are dry contacts... meaning they will either close or open when the thermostat calls.... no power on them unless you add a jumper so one side gets power... Terminals 5 and 6 are suppose to go the aquastat relay on the boiler to turn on the burner that box in the picture will never do that. It can only rob heat when another zone is telling the boiler to run. It isn't wired correctly. The diagram is in the link I have above. ^^

Ddentry

In this case the "boiler" is a standard hot water heater which only supplies hot water to these three zone circulators for the floor heat. It's on all of the time after I light the pilot in the fall (not a very efficient setup)... None of these three has any connection to an aquastat on the hot water heater.

So it seems my options seem to be:
1) Move all of the power/neutral wires from two of the controllers to the one connected to the thermostat

2) Connect one thermostat to one controller. Jumper from that controller to the second and then from the second to the third. Does anyone have a wiring diagram for that configuration? That would be easier, I think, than moving the power lines. I'm still a little fuzzy on the dry connector setup.

Thanks for sticking with me!

-David

Ironman

Truthfully, one circulator could have handled all three manifolds provided none of the floor loops exceed 300'. I realize that would mean re-piping and you may not want to go that far.

The simplest thing that you could do as far as the pump wiring would be to only use one SR501 and then wire the 2nd pump to the first in the pump's junction box, and the third to the second in like manner. That way you're spliced at the pumps and not the SR501.


The "5-6-6" terminals are the second set of contacts in the SR501. The "C" and "NO" should be used to bring on your boiler.

There should be some kind of mixing valve to limit the water temp to the floor and protect the boiler from flue gas condensation. Do you have this? Can you post some more pics of the boiler and its near piping?

Ddentry

House was built in 1790 with a major renovation about 13 years ago, that’s when the radiant floor heat was added.

The picture below shows three water heaters. The one on the far right is hot water for the house. The one in the middle feeds the one radiant floor heat zone in two bathrooms upstairs (circulator and controller on the far right).



The water heater on the left feeds the three zones in one large room that I’m trying to control with one thermostat. I suspect either the previous owner wanted granular control over the floor heat (hence the three zones/controllers/thermostats so close to each other) or the contractor made it seem he needed that…



I’m sure that there are better ways to do do this but I’m trying to sell the house and just want to change the control at this point. Other. more pressing projects, call…

Ironman

Then, there's no "T T" connection for the boiler, since you don't have one. The water heaters work off of their thermostats (the dials) on the gas valves.

What an inefficient mess.

STEVEusaPA

And the venting is pretty suspect.

Techman

How far apart are the T'stats? Zoning is typically a more efficient system and more comfortable.

Ddentry

Two of them are within three feet of each other and the third is about 10 feet away. It's a large eat-in kitchen. One zone is the slate-floor eating area, the other is the wood floor cooking part and the third is an attached living room area.

I could see the benefit of the living area (which is slightly separate) being on its own zone, but not the other two...

Thanks for the reply.

Techman

Do these stats have "remote slab sensors"?

Ddentry

Nope. I've got Nest and Ecobee thermostats elsewhere but these are just plain-jane mechanical Honeywells.

Leon82

Can you not just use a length of tstat wire to connect the other 2 end contacts to the first relay?

When one thermostat closes it will tell the 3 of them to energize the pumps. Because they are wired to the one tstat.

Leon82

Like this. Both zones will run of either thermostat. You would run it from box 1 to box 2 then to 3. This is the easiest

Solid_Fuel_Man

No! You cannot do that with three individual relays. They each have their own transformer and connecting 3 of them in parallel will blow the fuses or worse.

Taylor