Munchkin 140M with Taco circulator

akrug

I have Munchkin 140M R2 with a 925 Control Board. The way it was originally piped it appears to have Primary circulator Taco 0010-F3 without IFC on the return side. Currently, the indirect hot water tank is coming off the Secondary piping and using a Taco 007-F5. There are also 5 additional zones using Taco 00R-F6-1IFC pumps.

What I would like to do is repipe the indirect Super Stor hot water tank and potentially use the Vision 1 system with outdoor reset. According to the manuals it says to use Taco 0011 with IFC on the boiler supply side for the Super Stor, While the primary circulator pump should be a Taco 0010 with IFC piped on the return side.

Does anyone know if it would be possible to use the existing Taco 007-F5 without the IFC and pipe it directly off of the supply side of the boiler. Or is this pump too small or won't work because it is missing the IFC? It would be a short run of pipe. Most like a tee off the supply, then circulator, then a short run to a ninety into the Super Stor and then similar piping back out to the Return side on the boiler. Also, will the fact the Taco 0010 primary circulator pump on the boiler return not having an IFC cause problems? Just trying to use what I already have available.

Also, If I don't use the Vision 1 will this piping still work if the hot water tank calls for heating? So basically, repipe as I mentioned above and then have both the Primary 0010 circulator running on the return side of the boiler at the same time as the Taco 007 running on the supply side pushing into the hot water tank?

Thanks in advance for any insight anyone can provide!

Al

unclejohn

I always defer to the manual. Also some pictures would help me.

akrug

Here is a picture. I would move the hot water tank from the right side over to the left side of the boiler and keep it close. Then cap off the the supply and return pipes that the 5 secondary circulators are teed from (over to the side where the hot water tank circulator pump is currently). Hopefully the picture helps explain it.

akrug

I was also considering leaving the hot water tank in it's existing location, but it seems like it would complicate the piping, requiring me to either go behind or over the boiler to get to it. I figured I would keep it simple and short and move the tank to the left of the boiler. I just need to figure out if the circulators I have will suffice or am I forced to buy new ones.

unclejohn

If the pumps you have have caused no issues I think it would be fine.

akrug

I'm hoping that's the case, but I am changing the flow by moving the indirect hot water tank off the secondary piping to it's own separate piping. So I don't know if I need the bigger circulator to accomodate this. It will be a shorter run of pipe so maybe the bigger pump isn't necessary. Also neither the primary circulator nor the one that would be going directly to the Super Stor have "integrated flow check" valves. So I am wondering if this would cause issues.

unclejohn

What is the reason for the repipe? Why not just move the tank and reconnect the same way.

unclejohn

The primary pump has to run all the time. Come off the supply next to the PP or on the horizontal and tie the return behind the PP between the tee and the pipe hanger.

Alan (California Radiant) Forbes

From what I can tell, the Munchkin manual says to use a 0010 for the primary circulator and the pressure drop charts for the Superstor indicate a 0014. A Taco 0011 would be overkill.

The current 007 doesn't really move enough water through the heat Superstor exchanger. Recovery time must be slow and would be sped up with the correct circulator.

Those flow checks should always be included to prevent ghost flow.

Considering everything, why change the piping? Just add the Vision I control.

akrug

The Vision 1 piping in the manual seems to be different from what is attached above. It calls for the Super Stor to circulator to come directly off the supply pipe out of the boiler. When Vision 1 is being used and there is a call for hot water, Vision 1 will shut down the primary boiler circulator pump and only supply power to the Super Stor circulator to provide rapid hot water. So essentially the primary pump is removed from the system while hot water is called for. According to Vision 1 piping they say to use a 011 Taco for the hot water. I would prefer to us what I have, but not sure if it is just too weak.

HomerJSmith

The boiler is off the secondary circuit and the W/H is off the primary circuit as it is now configured. I'm going with the consensus, here, on what the primary and secondary are.

With the W/H on the primary circuit, it doesn't matter what size pump you use. It just affect the flow which affect recovery time of the hot water being produced. The way it is set up now the W/H is competing with the heating zones when they are calling for heat.

With your sys, you can't use Vision 1 as your W/H isn't on the secondary circuit (boiler). The reason that you need the proper size pump on the W/H circuit with Vision 1 is that the primary boiler pump turns off and stops putting water into the boiler and heating circuits and the W/H pump circuit turns on and pumps water thru the boiler and the W/H heat exchanger. Vision 1 works with a sensor for control and not a mechanical aquastat control as your present sys does.

You can still use the Vision1 reset function with your present setup, however, as the boiler water temperature drops as the outdoors gets warmer the heated water going to the W/H will also drop in temperature and the recovery time will be greater. If the programing in the Munchkin is set to a constant 180 deg to satisfy the W/H, why bother with an outdoor reset? With your present sys, the W/H is just another zone without priority or temperature adjustment.

To use Vision 1, pipe the W/H off the secondary with the correct size pump and follow the manuals instructions to a tee and program the Munchkin properly.

I can't see your Super Stor domestic hot water output very clearly, but I have never put a heat trap on one of my installations. If you are running your W/H at 125 degs, you are loosing a lot of capacity. Do you ever run out of hot water? I usually run my Vision 1 tanks with about 150 deg water with a tempering valve on the output. Caleffi make a great one.

Alan (California Radiant) Forbes

"The Vision 1 piping in the manual seems to be different from what is attached above. It calls for the Super Stor to circulator to come directly off the supply pipe out of the boiler. When Vision 1 is being used and there is a call for hot water, Vision 1 will shut down the primary boiler circulator pump and only supply power to the Super Stor circulator to provide rapid hot water. So essentially the primary pump is removed from the system while hot water is called for. According to Vision 1 piping they say to use a 011 Taco for the hot water. I would prefer to us what I have, but not sure if it is just too weak."

It all depends how you like to wire your pumps. I see that your circuit pumps are powered by your pump controller above the water heater and your primary pump is powered by the boiler. If you have both your circuit pumps and your primary pump wired through your pump control, you can have your primary pump come on when DHW calls. The Vision I will only be responsible for temperature control (DHW and outdoor reset).

Caleffi ZSR has a primary pump connection at the lower right.



And then position this jumper in the "on" position:



You would have to wire the water heater aquastat to both the pump control and the boiler.

So, it's either a bit more wiring or a bit more piping. Your choice.

clammy

If your going to add a vision one you should re pipe the boiler as suggested by htp piping diagrams and yes you will need checks valves on the pumps . I would suggest using the taco 011 or a grundfos 26-99 . I have a 80 piped as htp specs w checks on both supply and returns due to my heating system is low temp didn’t want any thermal migration from tank to system ( max heat temp 130 indirect at 135 and boiler set for tank maxes at 167 ) nothing worse then thermal migration from tank to system ends up cycling for tank due to it heat migrating from tank this is just my experiences w mid to low temp heating systems that are piped ps and using indirects . Hi temp goes to low .peace and good luck clammy

Zman

I don't think the 0010 is suitable for the boiler side. It is a high flow, low head circ in a medium flow high head application.
The 0011 is overkill.
I would suggest the 0014.

You should be able to do DHW priority and outdoor reset with your existing piping and some creative control work.

akrug

Thanks for all your feedback. One of the reasons I want to use the vision 1 is to have the boiler adjust the temperature going to the DHW when there is a call for hot water. Right now, I have to leave the boiler on at least 140 degrees all the time and the hot water tank aquastat at 120 degrees. I've realized over the past few months that I can get by heating the house with a lower temp boiler and would like to get the return into the condensing range of sub 130 degrees.

I redesigned and installed an entirely new HVAC duct system this past year and eliminated all the airleaks, and kinked flex duct, etc. It is now 90% hard pipe with very little flex unless it is a straight run. Airflow is probably double what it once was when the guys did the crappy job of installing it 10 years ago. I even had to turn down the speed on the blower motors on the air handlers. I then realized that the air temp coming out of registers in some places was north of 140 degrees and way too hot. That's when I started researching boiler temps and modcon boilers and realized there was a lot to be gained by lowering the boiler temp, but it works against the hot water tank. I guess that's how the installers originally got by with this system. They could design an install poorly laid ducts and then crank the temperature on the boiler up to 180 degrees and leave the fans blowing full speed. It could get by, but it was completely inefficient. My gas usage has come down significantly and I'd like to take it to the next level with the vision 1.

I'll review everyone's comments above and come up with a game plan. Thanks everyone!

Zman

Can you post a picture of your circulator controller as well as the control wiring on the munchy?

akrug

Is this what you are looking for? The wiring is a little messy at this juncture. I'm still cleaning things up and testing things out.

Zman

I think it could be done using existing piping and a DPDT relay.
Some of the guys that work on munchies regularly can hopefully assist.

akrug

I'm sure I could rewire it in someway to prioritize the DHW, but I'm not sure I would be able to get the boiler to automatically adjust it's temp to heat the hot water unless I use the boiler's control board. That's the dilemma I'm running into.

Alan (California Radiant) Forbes

With the addition of the Vision I control, you will be able to do that.

To be proactive, I would also upgrade from a 925 to a 926 motherboard.

Are there any Munchkin professionals in your area that can advise you or do the work?

akrug

Is there a big benefit to the 926 board? The boiler is now 12 years old. I don't want to go putting a ton of money into it if it's only going to be a small improvement. I know the boiler could last a lot longer, but being my luck it will probably crap out in a few years and require major repairs. Does anyone have any thoughts on life expectancy of this boiler?

HomerJSmith

The Munchkin will last as long as you care for it. Negligence breeds poor performance and a short life. I clean the HX between 3- 4 yrs. I do a combustion analysis at setup and at each cleaning. I make sure the water quality is up to par. My installations were correctly piped, which is why you need someone with hydronic training and why plumbers do fail to reach the mark. I am in awe, why some plumbers just can't follow the manufacturer's installation instructions. Go figure.

As to Vision 1, I stand by my previous post. Vision 1 is a big money saver and lightens the wear on the boiler.

Change the post purge to 100 sec.

Alan (California Radiant) Forbes

akrug said:

Is there a big benefit to the 926 board? The boiler is now 12 years old. I don't want to go putting a ton of money into it if it's only going to be a small improvement. I know the boiler could last a lot longer, but being my luck it will probably crap out in a few years and require major repairs. Does anyone have any thoughts on life expectancy of this boiler?

"The new 926 board has a much longer post purge. The 140 has a problem that after it shuts off, heat will rise from the HX and melt stuff in the flu blower. The new board runs a 90 second cool down so the HX cools enough so that won't happen. Upgrade both refractories while you're at it. It makes for a nice upgrade. The new board also raises the voltage to the flame sensor and makes the sparker a second flame sensor. Say goodbye to any F-09 problems." From Wayco Wayne 7/12/2009

I installed my Munchkin T50M in 2007 (radiant and DHW) and it started throwing out those F09 error messages last year. Replacing the board with the 926 version took care of the problem.

Has your boiler ever been cleaned and serviced? If not, then you may be on track about a soon mortality. I service just under 100 Munchkins and their lifespan is between 15 and 20 years. Keep in mind, ours is not a harsh environment and they don't have to work as hard as in colder climates.

akrug

I live in the Northeast outside of Boston, so we have our fair share of cold days. The boiler could probably use a servicing. I do most of my own repairs or at least I try to first before calling someone. So far I've been lucky and rarely have to get someone else involved. The boiler seems to be working fine right now but my experience tells me that with just about every appliance something eventually goes. I'm optimistic it is well made and will continue for much longer but you never know. Out of curiosity, what would have to break on a boiler like a Munchkin to basically say it is not worth fixing. Most of the time I end up swapping out control panels, blower motors, transformers, capacitors, etc on other equipment and am able to get it running again. Luckily with the Munchkin I've never had to do any repairs on it. I'm just curious at what stage would I have to junk a boiler like a Munchkin. Is it pretty serviceable and able to replace parts and keep it running. One concern I do have is the amount of hard water in my area. It seems to wreak havoc on a lot of other equipment around here. Also, does anyone know if running a Munchkin at a higher temp with hard water is better than running it at a lower condensing temp?

SuperTech

I'd always choose to run at the lowest possible temperature needed to heat the house. That's the goal, matching heat generated to the heat lost in the home.

If the heat exchanger fails I would consider replacing the Munchy

Rich_49

Zman said:

I don't think the 0010 is suitable for the boiler side. It is a high flow, low head circ in a medium flow high head application.
The 0011 is overkill.
I would suggest the 0014.

You should be able to do DHW priority and outdoor reset with your existing piping and some creative control work.

Zman

@Rich_49, do you how those circs fit the boilers curve?

Rich_49

Those circulator call outs are from HTP Zman . What is your question ?

Zman

@Rich_49
Sorry for the early morning typos.
I find that manufactures often suggest circs that don't match their recommended flow rates(I suspect that they make some compromises due to OEM pricing) . This appears to be one of those cases. I guess I am asking if you feel the recommended circs will provide the flow rates recommended in the manual?

akrug

I just picked up a taco 0011 IFC and a IFC replacement part for my existing 0010 that doesn't have the flow check installed. I'm hoping that I can just install the replacement part and create a 0010 IFC. I also picked up a 926 control board replacement for the 925 controller, but it's programmed for Munchkin 140M R1. I have a 140M R2. Does anyone know if I am able to reprogram it myself for an R2. Or will it work with my model as it is? I can return it if it won't work, but it was sitting on the shelf so I figured I'd grab it and figure it out when I got home.

akrug

I found a 926 for Revision 2 and returned the 926 for Revision 1. There isn't much information online that I could find, but it appears that the R1 can be reprogrammed for an R2, but you need to find the right person to do it.

I'm still not sure if it is worth the $350 ish price to move from a 925 R2 control board to the upgraded 926. It seems like there are some benefits, but I question if they are they worth the price tag.

Alan (California Radiant) Forbes

I buy all my Munchkin parts from Jupiter Sales:

https://www.jupiterheating.com/munchkin-boilers/7250P-731.html

You have to give them your model and serial numbers so they can program the new circuit board for you.

akrug

I was able to find the correct model at a plumbing supply place around here, which made it convenient. I installed the 926 board last night. Seems to be working well so far. I can't seem to find much information on the difference between the 925 and 926 boards online. I have read about the longer post purge cycle and the additional flame sensor capability. Are there any other improvements to the modulating capabilities or other efficiencies?

HomerJSmith

The circuit board is different, a better design. A 926 conversion requires a new display board that fits into the 925 display housing.

Most HTP wholesale distributors and contractors have the equipment to program the controller.

The 925 board ran hot, especially IC6. The 926 is vented and has better air flow.