Cast Iron to Pex Zone and Pump and Meter question

YeDIYer

Hello Everyone,



I'm new here and a DIY'er to start things off. My project this past winter was removing my old cast iron pipes and replacing them with Pex. This is a topic that is on this site quite a bit, but I couldn't find much information for the stage I'm at now. Keep in mind, I've been consulting plumbers along the way, and am at a crossroads. Here's my scenario. The house was built in 1916, one zone. I ran Pex to all the rads on the first floor, will be adding two in the basement, and ran pex to where the runs for the second floor go up (they'll remain iron in the walls). I created 3 supply manifolds to break the house up into 3 zones. The supply coming from the furnace is 1.5" so I used 1.25" manifold with 3/4" pex ports. The pump is a Bell & Gossett series 100 with 1.5" supply and return. Here is where my dilema is. I plan on getting a control board (likely an argo az3) and three zone valves. One plumber says to do 3 2 wire zone valves and use the one pump and that should be fine, while the other says use 3 3 wire zone valves with 3 pumps. There is a significant cost difference between the two scenarios. Any thoughts on what the better option would be? Also, I'm looking for in-line pex flow meters that will meter high enough for my application (that aren't $100 each as I will have 11 returns). Thanks in advance for your help.

Rich_49

DIYer

Is the piping done to each radiator as a homerun ?  If this is the case I would suggest one pump and 3 zone valves . I also suggest a variable speed Delta T pump . Sounds like you have generously sized manifolds and the piping to the rads is 3/4" so your head loss should be low , bing that these are radiators you can run a 30* Delta T and have really nice results , low head loss , low flow . Save your first cost money and save money every month and tell the pump fan to go away . 

If you use the Delta T pump you really can live without the flow meters also

Robert_H

another option

Is to drop the zone valves and use TRVs on on your radiators, if you have room to add them.  The TRVs with the variable speed pump work very nice together. I agree with Rich, with the low head loss of your system and depending on your load, you might be able to get by with one circulator like a TACO Bumble Bee. And with the TRVs you have eliminated the three electrical circuits for the zone valves.

I put a system like this in my house this year and could not be happier, it is simple and effective. I had my eye on using a Delta-T circ but because of how small my system is I could not use Bumble Bee. The B&G ecocirc Auto (Delta-P) was the only Variable that could go low enough for my low flow and head. 

YeDIYer

Pump reply

Rich, thank you for your response. Do you suggest then that I replace my current Bell & Gossett? Also, the main reason behind meters was so I could adjust the flow per rad, as yes, they are all homeruns.

YeDIYer

TRV's

Hello Robert, thanks for the information. I liked the idea of TRV's when I was planning this project. However, after talking with several local plumbers of different companies, they all talked me out of it. I live in a very variable and cold climate and supposedly (same answer from the majority of plumbers in the area) the TRV's have troubles with the high temperature swings and are actually less efficient than the zone valve setup? I don't know how much of that is true, but decided against it after several of the same answers. My system isn't very big at all (I don't think), I have two large rads on the first floor. I would they're around 18-20" wide and easily 6' long. On top of that, there are two very small rads in the kitchen on the first floor. The second floor has 5 rads, 3 of which are very close in size, 8-12" wide and about 3' long, but two small rads for the bathroom. I then planned on adding two extra rads to the exisitng one in the basement, totalling 12 rads. I guess this is where I need to do some more learning in terms of what I will need for a pump. I was thinking I could use my existing B&G, hook it up to the Argo control panel controlling 3 zone valves with flow meters and valves on the return manifold for fine tuning.

Robert_H

First off YeDIYer

 I am not a professional here. Just a home owner with a passion for this stuff. I  designed my system, with a lot of help, and I installed it. I keep a log book and record readings on my system every day to help me with fine tuning it.  It’s my baby, warts and all, So take what I say with the appropriate grains of salt.



I’m curious, Where do you live and What boiler do you have?



What your local plumbers are saying makes sense but so far I have not heard or read any remarks about TRV performance in variable environments. We have a had a pretty variable year here in CT and with ODR/ TRVs and a variable speed pump, I’m happy!  I'm curious so I'm going to dig on that a little.  Let’s see what the pros come back with.



I will say this about pump sizing, you need to know the flow requirements and the worst case head loss the pump will see. To determine flow you need to do a heat loss estimate on your house if you haven't done so.   



Simple app that a lot of people use.

http://www.slantfin.com/homeowners-page/ipadapp.html



Search this forum for “heat loss” and there are several other recommendations. But I will say this, I spent a month on my heat loss, building a spreadsheet with all the various construction components because none of the available programs covered all the Hodge podge construction methods in my house.  In the end my Heat Loss Calc was 42100. The simple applications were giving me something like 44000. Lesson learned, keep it simple!



Taco has several good basic hydronic courses available including heat loss calculations and circulator selection available at:

http://flopro.taco-hvac.com/flopro_u.html#



Also, Caleffi has some great learning resources at:

 http://www.caleffi.us/caleffi/en_US/Site/Technical_library/Idraulica_magazine/index.sdo



Good luck!

YeDIYer

TRV's s'more

Hello Robert,



My apologies if I came across arrogantly. Was not my intent. I live in Northern Mn where we're currently experiencing -20 on the thermometer, and something like -48 with wind. I don't doubt the TRV's work great, and I may re-visit the idea very shortly per a lot of suggestions on this site. I tend not to write something off until I've tried it, but was thinking it might be an expensive trial (If I end up having to go the originally planned route).



As for the pump sizing, thank you so so much for the information. I've been reading up a lot on pumps now and requirements, etc... but this app looks quite useful. I will also dig more into this site about heat loss.



Lastly, thanks for all of your help and responses. I've been a part of forums in the past where replies take months, so this is very helpful. I will look into both of those training and information sites as well. Thanks again



On another note, if I end up going the route of the variable speed pump, argo control panel, and 3 zone valves, do you know (or anyone) of a good meter or flow gauge I can put on my return manifold for fine tuning?

Robert_H

"My apologies if I came across arrogantly. "

You did not come across like that to me, at all.

Just a guy asking for help.

Rich_49

Caleffi

Probably has the easiest and best flow control I have ever used . They are in the Mid west .

   The plumbers in your area must not be trained very well or have a very small knowledge of anything that is not the norm . Radiators and TRVs will work just fine where you are . That being said you do not require them on your system . The zone valves and 1 bumble bee will work just fine , Does not matter where you are .  Run them at a 30-40 Degree Delta T and let them suck every bit of energy they can from the fluid .  

YeDIYer

Bumble Bee

Rich,



Thanks for your reply. So with the bumble bee, would I still need the Argo zone control board? Or, could I hook 3 zones directly to the pump?

Rich_49

Controls

are always a worthwhile investment . They keep things neat and organized , are not complicated and all in all inexpensive . Taco ZVC or the Argo you mention are fine .

YeDIYer

Controls

Thank you everyone for all of your help. After doing a bit more research into the TRV's vs pump + control board + zone valves, I think I'd be better off going the route of the zone valves ( I have 12 radiators total) and pump and board. Which, brings me to my next (and hopefully final) question. When setting this all up, I want to be able to fine tune the flow to my radiators. That being the case, is there a way to valve and monitor the return lines so that flow is even through out? I was thinking perhaps a pressure gauge before the valve and making sure its similar across the board, but does this necessarily mean flow is even? I have been looking into flow meters, but it seems the majority only go up to 8 gpm, is this enough?

Robert_H

Caleffi 132 series quick setter

I have one, it reads 2-8 gpm (3/4 in), well made and works great. If you put one on each zone that wouldn't be too costly. You shouldn't need to more than 8 GPM in you loops It depends on how the rads are piped in each zone. However, if you want to put one on each rad return, that could add up a bit.



http://www.caleffi.us/caleffi/en_US/Site/Products/Product_news/args/detail/~Details~News~news_detail_0000908/type/newshome/index.sdo

YeDIYer

Caleffi valve

Interesting! I wasn't really thinking per zone, but I'm now wondering if that will work. Could be a very good alternative. Currently, each radiator is home run to the manifold, hence the though of a valve per rad for balancing. If I put one of these on each manifold, will that potentially perform the same duty?

Robert_H

Not realy,

one on each manifold would only control the flow to that manifold and not allow you to balance the flow to each load which allows you to compensate for different pipe length (head loss).

with the large pipe size you have and low head loss in your distribution you may not have to worry too much about balancing. If It were me and I was on a tight budget I would try it without balancing valves you can always add them later. You might find that you don't need it at all or only on one zone say that has a rad or two on really different lengths.

YeDIYer

Heat Loss

Alright, here it is. Finally got the time to track down and figure it all out ( I think). My heat loss for 1436 sq. ft home is 265766. That sound correct possibly in the ball park? Decent windows up stairs, brick and stucco exterior, somewhat insulated walls. Which, bring me to my next question. I need to order a pump and zone valves. Was going to get a bumblebee (taco hec-2), but I'm not sure if I need one per zone (3 total) or one for all 3 zones? Also, I have 1 1/4" manifold with 3/4 pex hook-ups. What would be a good (thread in vs. sweat in) zone valve? Thanks in advance.

YeDIYer

Almost forgot

I also plan on adding an argo control board.

SWEI

265,766 BTUs per hour?

Are you sure you didn't insert an extra digit above?  If it were 26,576 I'd say you're probably close.

YeDIYer

yup -typo

My bad. 25,766 is it.

SWEI

18 BTUs per square foot

sounds about right to me.

YeDIYer

Pump / circ and zone valves update

Alright everyone, I'm 99% done with my manifolds and am looking into purchasing for the next phase. Here's what I'm thinking:



replace my current pump (Bell & Gosset series 100) with a Taco HEC-2 Bumble Bee seen here:

http://www.amazon.com/gp/product/B00D23LKH4/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=ALEI89KSU1BD6





Purchase 3 White Rodgers 3 wire zone valves (1 1/4" to match my manifold ) seen here:

http://www.amazon.com/gp/product/B0051PUX0Q/ref=ox_sc_act_title_4?ie=UTF8&psc=1&smid=A26GX4M4E8K5KR



And then purchase the Argo AZ-3 seen here:

http://www.globalindustrial.com/p/hvac/controls/zoning-controls/3-zone-relay-for-zone-valves-az-3



So, my question is, will this all work together? I see the zone valves are 24 VAC. And, will this one bumblebee be enough to replace the series 100 ? Thanks everyone in advance

Robert_H

Diagram

at this point people might be able to give you better feedback if you post a diagram of what you plan to do.

R

YeDIYer

diagram of plan

Hello All, here is the diagram of what I plan on doing. The manifolds are done, and the only reason I broke the return into two was to save some space. Thanks in advance for your help.

YeDIYer

another format for diagram

Here is a jpg in case the other one doesn't work.

Mark Eatherton

Sorry for being late to the discussion....

But your local contractors are wrong about TRVs. I live with them in 3 houses, and I can tell you that the comfort and efficiency are unmatched. A good system design will incorporate some sort of indoor feedback (thermostat) located in a worst case scenario zone, with NO TRVS on that "reference " radiator .



Their response is typical. If you don't understand the application of the technology, then trash it in favor of one you do understand...



If TRVs are SO bad, why are they the predominant means of control in the WORLD?



Look at Oventrop, Danfoss, Honeywell and more for quality products. Water treatment is critical regardless of WHAT is being used for control, and without it, ALL methods of control will have issues, including zone valves and TRVs.



ME

Robert_H

Do the math before you buy

Before you pull the trigger on the Bumble Bee make sure you know what it is going to do for you. I’m saying this because we are both small system owners with big easy flowing radiators (as in low head loss). Your smallest pipe is ¾” so you are even lower head than I am. The nice ECM, Variable Speed Pumps are designed to cover a wide range and we are at the low end of it.   Look at the bumble bee curve, there is an envelope for the Delta T mode, if you fall below that envelope you will just ride the low speed curve as if it was a fixed speed pump. You should calculate your system head and flow rate and plot it on the pump curve. (the links I provided earlier should help) When I did, I found that my system would only be in the Delta –T envelope on design day.  I would still be getting the benefit of a ECM circulator but I wanted to take advantage Delta pumping. I had already purchased the Bumble Bee and fortunately was able to return it once I showed the problem to the distributor.  The Taco rep even confirmed my conclusions.  I WAS disappointed that I couldn’t use a Delta T circulator but I am very satisfied with the B&G ecocirc Auto (Delta-P) that I chose.  



You should do the math and make an informed decision.

YeDIYer

Pump and calculations

Hello Robert,



Thank you for the reply, it is very good advice. I will do some math and get back to this thread. Perhaps I could get away with even keeping my current pump (although I don't think it's very efficient, which is one of the main reason for this conversion). Do you have thoughts on the zone valves and Argo AZ3?

Robert_H

No zone valves in my life so far

No experience, so I cant comment on the zone valves or controls. You existing pump seems like overkill to me me but your calculations should get you the truth on that.