Taco RMB

Joe Mattiello · August 2006

Reason for the offsets radiant supply and return connections are to allow direct conection to manifolds as shown in front page of literature. see attached.
You can use the pump contact on the RMB control panel to energize a pump dedicated to the RMB. Of course you can customize drawings to facilitate wiring for your own personal use. Incidentally the radiant visio stencils will be available soon. You can currently access the zonecontrol stencil. For your convenience I have attached a link.

http://www.taco-hvac.com/en/advanced_library.html

Bob Bona_4 · August 2006

RMB anyone?

So,I tangled with my first Taco RMB today. I think it may have won.

Major ingenuity with having injection mixing/controls in one package, and simplified piping connections..BUT-

What the heck were they thinking?

-and how, exactly, is one to attach the BX from the primary pump to the RMB, w/o having to breakout the 1/2" hole saw to create a knockout? And then, trim the green plastic jacket for clearance around said KO?

-once we have created a KO, how does one safely, and OEM approved-ly run the circ wires to the RMB's board? UL anyone?

- Did anyone realize that circ's have a neutral wire that needs a tap for on the RMB? A pigtail behind the board to the N spade connector just isn't cool, practical, servicable, or safe, IMO.

-and then, hopefully, all the high voltage will shoehorn into the tiny space provided behind the board w/o shorts, loose connections, and pinches. Geesh!

-On the low voltage side, same problem. No space for dressing wires behind the board, although there is a cut out in the RMB's left side for low volt wire entry.

-The fun will start when after all this is crammed together, and one of the pumps need service. It all will have to be taken apart. Not cool.

-I can think of a bunch of ways to mount this thing better than having to dissasemble the unit entirely just to get to the mounting holes. External tabs, people, external tabs!

-Again, the green cover holds every service action hostage with it blocking everything, and the need to disconnect everything just to get it off the pump bodies.

-Flat plate Xchangers usually have unions at the connections for service. Unions would be a good thing here at the four connections.

-The receptacle type plug for the RMB is a nice touch, but sort of pointless when all other connections are hardwired.

-On that subject, we are back to the tiny space provided to make the line cord connections to the board (see above)

That's all I can think of for now. I gotta tell you guys, make sure you allow enough time to deal with this stuff. I can appreciate the consolidation of a mixing station, but I may take a big raincheck next time! Back to the drawing board, Taco, and post haste!

Any comments/ further observations? I'm a big wuss?

kevin coppinger_4 · August 2006

I have not....

used one , but I have talked w/ one guy who had to service one....he was not impressed w/ the wiring...as w/ anything "new" it is some trial and error...I am sure Taco will listen.....kpc

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Ted_9 · August 2006

pump

the two I did were RMB-1 without the plate exchanger. Also I didnt connect the external pump to the /Rmb so I just pluged it in and then connected the low voltage. The circ was connected to an sr control.

Everything you said about dismantling the rmb is true though.

I still like the unit and will use it again.

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John White · August 2006

laundry list

Bob,
This is a great laundry list of observations. I will have Mark Chaffee get in touch with you, as we are only trying to make things easier for people, not more complicated. Remember, Taco's desire is to be "The easiest company to do business with," so these kinds of comments are really valuable, specially when addressed to Taco and our product managers.
We'll get back to you.
Anyone else???
Thanks,
Johnny White

Jeff Lawrence_24 · August 2006

Where else but the Wall?

Taco's good equipment and their Prez is the best.

Johnny, for once and for all, is it Ta-co or Tay-co? Does it make a differnce?

DanHolohan · August 2006

It's like this:

Ta-co is for eating. Tay-co is for heating. Simple!

Jed_2 · August 2006

Ditto

to Bob's list. One addition I would bring up, as pointed out to me by a Contractor; the offset location of the S/R taps on both sides of the block caused a little aggrevation in connection alignment with the systems. It's clear, based on the internal architechture of the block, the offsets are necessary, but he is a pecise guy, and that irritated him.

On another, unrelated note; the wiring diagrams on your website for the RMB, among others, are great, but not exhaustive, as you might agree. Could those PDF's somehow be made available as interactive stencil Masters for, say, Visio, as the visio stencil library allows? Sometimes the specific system control logic requires some minor modifications to those diagrams. Example: RMB11 shows 2 SR503-EXP's, with the primary circ powered from ZR off the mixed temp zones control relay.That's good, but I don't want the two controls integrated through the four low voltage interface terminals. No DHW priority required. The Hi-Temp zones are piped parallel to the boiler( as shown in RMB11), so I don't need the primary circ. unless RMB demand calls. I need to re-route boiler demand from RFH zones demand through the boiler contact on the RMB to the boiler demand circuit(XX). And provide boiler and zone demand only through the hi-temp system circuit. Obviously there will be some overlapping, with regard to the primary circ, but I want the primary circ to come on only when the RMB receives a demand, through ZR on the RFH control relay.

Anyway, to use RMB11 drawing, I would like to be able to modify it. Is that possible, or is there some legal restriction to this capability?

Jed

Weezbo · August 2006

You can call it tay co if you like in America:)

however you will likely starve in Mexico:)

i like taco mixing blocks and the X block and the 2,3,4 way I series and the ESP henceforth known only as EBV's

when you want to make the wiring tidy i think a half inch K.O. out the back behind the surface and connected to a box it the best way to go. it just looks neater than having a very ameturish black utility cord hanging from the side of the box...as the pump block can support an additional pump it can allow you to connect to a seperate pump ...the only minor technicality i see with that is a friend of mine installed one a couple years ago and plugged the wrong jack connector to the available connector for the extra pump and frazzed something and had to go play "stepnnFetch" after a new control. he has since put at least 6 more in service and likes them.

the good part about the cord Bob is that you can when on the run, put the block on manual, plug it in ,open the zones and "You Got Heat "

deal with the finer options of wiring the next day...

Jed_2 · August 2006

That's great, Joe

but, with the BTU flow capacity of the RMB, I would rarely spec it for a single manifold arrangement. It is usually applied in a multi-zone set up, hence; a S/R header arrangement, with multi-zone service to similar temp zones. Those S/R return pipes are not offset as a manifold is, so an offset creates a hassle. I have all the current stencils. Looking forward to the Radiant stencils. Taco products are great; I've just started stocking the i-valves. I will corner Bruce Marshall later this month on the pump contact option.

Thanks, Jed

Jed

Taco RMB

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