Adding honeywell ra889a to system with external transformer

animatt

Hello having slight issues with external transformer.

System was a 5 zone heating system connected to NG boiler.



There is an external transformer. 40va.



The boiler was fired off the end switches in the zone valves. The boiler calls the circulating pump.



External transformer is connected to zone valves( honeywell .32amp 24v) with a single wire to a yellow wire(all in parallel). The other yellow wire of the zone valves are connected to its respective thermostat. The returning wires from (2-wire digital) thermostats connect to external transformer in parallel as well.



Now I am upgrading system and it will have 6 zone valves to the one circulating pump.

It will have additional zone valves with its own circulator. These 2 zones will be for radiant floor heat that will be primarily be solar heated, but also will have the option to be run off boiler.



So what I am trying to do for the 6 zone valves that run baseboard heaters.



I will split the 6 zone valves between 2 external transformers. 4 to one of them and 2 to the other transformer.



The end switches in the zone valves will call boiler. But instead of having boiler turn on circulating pump, I want to do that with a relay. Specifically I have on hand 2 honeywell ra889a . Basically to the first question is how do I hook the Ra889a to the current circuits.



I see something about it in the manual but seems incomplete with my current knowledge. I could test some connections but rather not fry anything so I am here



So I would like to connect the ra889a to the current 24v circuits. Just not sure of what terminals I should use. R(t) W(t) and/or C and where to connect them in the system.



I have 2 circuits. each with its own external transformer. connected like stated above to zone valves, valves to thermostats, and stats back to relay.



So any help connecting the Ra889a into those 2 circuits would be very greatly appreciated.



Let me know if you need any other information.



matthew wright



added 2 files to hopefully explain it a bit better

animatt

honeywell Ra889a documentation

Just adding documentation for the honeywell Ra889a.

Zman

Sequence

I think you're all set with the wiring of the transformer to the t-stats.



If you take the end switches from the 2 zone valves off the boiler and connect them to R(T) and W(T), this will enable the pump relay. You have 120v power wired to COM and the pump wired to N.O.

When this happens the relay will close terminals X1 and X2. If you connect these to the boiler TT terminals you are all set.

Carl

animatt

New drawing of how I understand your post

Attaching a new drawing of how I am understanding your post.



Makes sense this way. Also do not need to worry about transformers being in phase with one another.



Please confirm If I have it alright

Zman

That will do

Yup that's it.

I would wire all the controls and transformers to the same 120v circuit. It might save someone a headache on modifications down the road.

Carl

animatt

Definately

I already have the circuit setup.



Not sure to code. But I have a main switch that controls everything.



This switch will control 6 outlets. Each transformer is wired up with a plug. So just plug in and it has juice.

2 transformers, 3 relays, and 1 boiler controller. I personally find this much easier myself.



Also each relay will control 2 outlets. This way the loads can just be plugged in.



I am going to make up a much nicer diagram and laminate it and hang it there as well.



Thanks for your help.



Will be posting an updated drawing of whole system tonight including the radiant floor controls.



Matthew

animatt

Full Layout

Attaching a Drawing of full layout. Also will describe what I am trying to do.



First of all the upper part of the drawing is just a cleaner version of before.



2 40va transformers. 1 transformer has 4 zone valves and the other has 2 zone valve.



Both these sections connect to the Ra889a via their end switches. The relay then calls the boiler and circulating pump for the baseboard heats.







The radiant in floor is a little more complex but not much. There are 2 radiant floor loops which draw power from the previous transformer that only had 2 zones connected to it. This will leave each transformer with 4 zone valves to power.



If one of these 2 zone valves call for heat it will start another circulator connected to the other Ra889a relay. These zone valve are also connected to the Relay by their end switches.



The 24v relay on this relay x1, and x2 terminals gets wired in series with a thermostat that measures tempature of solar thermal storage tank. The thermostat will be set in heating mode. So if it is set to 90 degrees as long as tank is warmer than 90 degrees the 3rd relay the ra832a will not activate, but if temps drop below preset temp the relay fires cause the boiler to run, as well as activating a 120volt 3 way valve. If 3 way valve opens water coming from radiant floors goes to boiler thus the need to fire it. If the valve is not open water goes to a submerged coil in the solar thermal tank where it picks up heat and comes back to feed either,or/both of the radiant floor loops. In reality this thermostat will be probably set at 80F to pull more heat out of the tank.



This entire system allows the baseboards to do all the heating, with solar providing supplemental heating. Currently thermal storage tank is very near completion(just missing a bit of hx work) but solar collectors are a bit in the future. So until solar is installed the radiant floor heat can still be run by the boiler. Also if solar does not provide the expected contribution the floors could still be heating in cloudy stretches of weather.



Thermal Tank depending on exactly where it is filled to will have atleast 1000 gallon capacity but possible as much as 1250 gallons. Tank is insulated to roughly R50 on all sides(6). The R50 was to make up for the fairly large surface area of the tank roughly 320sqft. Tank is inside a basement so not like it is in ambient winter air, but still at 50F basement temp and 100F water temp in tank I wanted to reduce heat loss. A bit less than 8000btus per day. Not so bad.



Anyway getting off track of the post. The idea is the check the wiring diagram.

also attached is document for Ra832a



Matthew

Zman

Looks good

I don't see any issues on the wiring side.

What program are you drawing with?

Carl

animatt

drawing program

First off let me say thank you very much. You were alot of help.



One last question comes to mind. Looking at the connections to the boiler. Does it matter which/how the x1,x2 and X terminals are hooked to the T of the boiler. To be more clear do I have to worry about the phase of the connection.



If I was using all Ra889a relay I would just keep both x1's to a t and both x2's to the other.

But since The ra832a is labeled only X rather than X1,X2 I am not sure.



Should the upper most X terminal in each relay be hooked together?

Right now I have it drawn the opposite. I just drew it without thinking. That seems to be the only spot where 2 different power sources are wired together.





Back to your question. I am sure there are easier programs out there but I used http://www.gimp.org/



I first started just editing the original scans. I was in a rush to get a solution. SO I was not worried about pretty. Family is getting together for christmas but more so for new years and would like to have the radiant floors working.



So program is http://www.gimp.org/

Yesterday I started editing the scan files again and well I just did not like the quality. I figured I would need to make a cleaner permanent version anyway. So I started from scratch. I tried to keep colors consistent in the diagram. Wiring end switches green, external transformer circuits in pink, Low voltage relays in red.



I am sure there are much better programs out there for quickly drawing system out. Basically I manually edited most things. Gimp is a very strong image editing program, but well my imagine is very simple. Idea was just to keep things clean.



Thanks again

MAtthew

Zman

Carol Fey

I used to seriously over think electrical circuits. I picked up a couple of Carol Fey books and it all started making sense. The thing she says that I repeat to myself when I get confused, is that everything in a simple electric circuit is either a power supply, a switch or a load. Your boiler TT is a power supply on one side. It is looking for a switch to connect it to the load on the other side. In other words it doesn't matter which way you connect it. The relay is just a switch.

Thanks for the link.

Carl

animatt

One last question

I was wondering if there was a way in the Ra889a to connect into the external transformer, thermostat, zone valve circuit.





I see the advantage of wiring like you said and I have drawn above, but was thinking if the valves did not have end switches how would I wire that.



Basically my original question. There turned out to be a better answer for my original question than what I was asking for, but still curious on how to wire it.



I am not sure how the r, W, and C terminal relate.



I drew something, but seems it would still use internal transformer as well. Not sure if there would be an issue If I wired things up like that.



Or maybe instead of connecting to the R terminal I used the C. I come back to the C terminal as the little manual states something about it. Basically trying to understand those terminal and how they work.

Zman

I don't think...

I don't think that will work. The t-stat is a single pole switch. What you are doing is running parallel loads and power supplies through a single pole switch.

I believe the "C" on the relay is intended for 3 wire-t stats  like some of the programmable ones out there.

Carl

Empire_2

Wiring diagram???

Animatt is that a program you use to draw up wiring diagrams?  I like the looks of it and I am wondering if it is available somewhere.  It make examples look clear and neat.  Let me know please.



Thanks, Merry Christmas



Mike T.

animatt

Not a diagram program

just a picture editing program. Takes a little bit of time. Surely more time than a dedicated program but www.gimp.com this program is fairly easy to use. A quick sketch on paper may make drawing it easier/ quicker.

Empire_2

Yea it figures...

Just my luck...lol  I use graph paper and a template with different size circles, squares, and little squiggly things...  Works OK.  I just thought there was a better way.  Hey it can be my new invention....



Peace;



Mike T.