Re-Plumbing Boiler to add zones

Alan(CaliforniaRadiant)Forbes

Taco controller you get, make sure it has a "with priority zoning" option and leave that zone open for your future indirect.

Once you install the indirect, wire it to the Taco controller and make sure the switch inside is moved to the "priority" setting. Your boiler does not need to maintain temperature for an indirect; it will be a "cold start" system. You only need to maintain temperatures for your current tankless coil.

P.S. Now that you're zoning your system, it would be a good idea to pipe primary-secondary to make sure you get proper flow through the boiler.


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Paul Flansburg

Re-Plumb of boiler to add zones

Hi,

I am in the process of re-plumbing my boiler to add two more zones, acutally three. Currently I have a Weil Mclain WTGO-4 package boiler. I have already built the manafold and plumb the returns. Working on the connections to the radiators.

My questions are:
I believe that I want to use a Taco503 control for two of the three zones. The two zones will be used for heating. The third zone will be added later for an indirect water heater, agian added later. The tankless water heater is doing OK, but want to be ready when it goes.

Will the Taco503 controls work now and later?
Can I wire in the Taco503 to the current boiler so that the DOMESTIC HOT WATER still has priority over the heating?
Later, when I put in the indirect water heater how do wire this to maintain the temp of the boiler? Do I need to maintain a minimum/maximum temp. of the boiler? Is there a better more economical way to accomplish this?

I'm trying to be as clear as possible by writing. If there are WEB sites or books that can help me on this I would appreiciate some direction to them.

Best Regards and TIA,
Paul Flansburg

Paul Flansburg

Whichever

Thanks Alan,

But I don't understand what you mean by "Now that you're zoning your system, it would be a good idea to pipe primary-secondary to make sure you get proper flow through the boiler". Could you please explain?

Also, with a cold start boiler, I assume that the boiler will sit at 0 degree's until a thermostat or the indirec calls for hot water? What tells the circ's that the temp. is OK and to start pumping water?

TIA,
Paul

Unknown

Paul

Which model aquastat do you currently have ? To go one step further with the Weil Mclain once you install the indirect I would recommend an 8124 aquastat . You can integrate that with a multizone relay to keep the boiler at a minimum temp until there is a call for heat . I would advise against making the boiler cold start because the sections are put together with neoprene o rings , as well as the coil . From room temp to blazing hot thousands of times will put alot of stress on those joints . This is definitely not a frequent occurance , but every Weil we replace leaks at the O rings . Keeping the boiler a bit warm all the time will lessen that impact as well as keep the fire side of the boiler a bit cleaner than cold start . It'll also give you less of a recovery time to replenish the hot water with an indirect .

The Taco website has a downloadable file with a bunch of different ways to wire up your boiler and indirect . I would buy a multizone relay with built in priority and a few extra zones spots for any future additions .

Paul Flansburg

Ron

Thanks for the response Ron, I like the idea of keeping the boiler at temp. around 100 to 160 degree's. I am looking into using the Taco SR503 controller. It has two zones for heating and one priority zone for domestic hot water. The 503 will be used first for the two zones until I add the indirect.

I currently have a Honeywell Triple Aquastat type L8124A which came withthe package boiler for the hot water. This will eventually go away when I add the indirect.

I guess I need to understand the 8124. Don't mind a little reading and learning.

Another question, since I won't be going right away with the indirect, how do I setup the Taco503 ant the Honeywell so that the hot water has priority over the circ's?

TIA,
Paul

Unknown

Go with

the SR504 - that extra zone will be maybe 20 bucks more , but it'll pay for itself in spades if you decide to add a future zone - after the indirect .

I just checked the Taco website , but couldn't find the downloadable file . That's OK though , the relay itself comes with detailed instructions on how to wire it in with an 8124 aquastat . It'll work fine with either a coil or an indirect . With the coil , you'll want to keep the low setting on the 8124 high - I have a coil and mine is set at 170 . 190 is my high limit .

Paul Flansburg

Thanks Ron

Will have a look at the SR504. Not sure if I need the three zones since I have only an up stairs and the room downstairs that I'm almost done with. The SR503 has the two zones and the hot water, but will still check the price difference between the two.

Regards,
Paul

Alan(CaliforniaRadiant)Forbes

Ron, Jr.

Thanks for correcting me, Ron. That's good information to know re: Weil-McLain.

Alan

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Ron Schroeder

Paul,

If you are not doing a true cold start, make sure that the Low Limit is not too low. If you set it below 125, you will get condensation in the boiler.

Is your fuel oil?

The electronic replacement for the 8124 (7124, I think)is a good option. Some of them have an adjustable Hi Limit Differential. Using a wider differential will save you some fuel.

Dan's book "Pumping Away and other really cool piping options for hydronic systems" is a very good resourse for piping. I highly reccomend it.

Ron

J.C.A._3

Paul,

I like what Ron said about not letting this puppy go cold, and also what Ron said about keeping the temp. over 120°.
If you still have the wiring diagram for the 8124, it shows you how to wire the 120V feed to the SR503 through the ZC/ZR terminals, and maintain the low limit abiity.It will only be powered when the low limit is satisfied, and will only "liven up a calling zone" when the boiler is at or above low limit temps. Chris

Joe Mattiello

The SR503 will work for you

Good Morning Guy’s
The SR503 is a good candidate for your application now, and will do a nice job for you in the future. To facilitate the wiring for a future indirect water heater, put the two heat zones on 2, and 3 reserving zone 1 for the indirect. Because you have a tankless coil, you have a legitimate concern about prioritizing the coil. You can accomplish that by following the alternative wiring diagram on the instruction sheet for the SR503. Simply move the factory installed jumper from ZC/H terminals to H X1, and bring ZC, and ZR down to ZC/ZR on the L8124 ZC/ZR using 14 gauge wire minimum. This will prioritize the coil, by not sending 120 through ZC terminal on the 8124 until the minimum temperature setting is satisfied. This will also circumvent C1/C2 terminals reserving them for another zone should you have a circulator tied in there now. When you’re ready for the indirect, you can change over to the cold start boiler wiring diagram, and prioritize the domestic through the priority feature on the SR503. At that time you can decide to replace the L8124, with a L8148 and run as a cold start, but keep in mind cold start means dropping the boiler temperature down to ambient and not operating below the safety threshold for non condensing type boilers. Hopefully this helps you




Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com

Tony G

Thanks for the input

All,

This is great info. and I will be finishing off the job hopefully this weekend. Going to take advantage of the tax free weekend here in Mass.

What I plan on doing is, keeping a min temp. around 160F and using the SR503. Trying to find it cheaper that $86. Then, when ready for the indirect I'll finish that plumbing and most likely go with a 40gal Weil Mclain gold series unit. Not sure on the cost but the performance numbers look good.

Any other thoughts? Something that I missed.

TIA,
Paul

Liberal Lenny

SR503

why not try the expanable control it will give you the option of using the Taco boiler reset control (PC 700)outdoor reset, also you can use plug in cards for Post purge ( PC 600),Priority protection ( PC605). I would heed the advice of not making this boiler a cold start, in fact I may look into replacing the boiler all together. Good luck you have some good advice from some real sharp guys especially from my two favorite Joes, Joe from Taco and Joe from Buderus!

Paul Flansburg

Cold Start

Hi Lenny,

Well, first thing, the boiler will not be made into a "cold Start" I think I will keep around 160 - 170. As for the other modifications, boiler is only 6 yrs old, no new boiler here. Budget is another issue. With me doing the work I figure it's going to cost around $250.00. That's my budget.

And with the knowledge that I gain from doing the work...PRICELESS!!

Thanks to everyone who replied......I'll post when she's up and running.

Paul