Munchkin control strategy

bobbyg_17

if your familiar with controls....use the Taco SR506, but for the dhw zone, have the circulator contacts go to another relay which can have two sets of contacts.

This new relay would 1."enable" the zone circulator and 2. "enable" the dhw contacts for the vision 1.

The vision 1 dhw, you have the option of using the sensor or a aquastat. I think that would allow you to use the two temps.

Frank_63

Munchkin control strategy

I have a Munchkin 80M boiler, 925 controller, with P/S piping with a Taco 007 on the boiler loop. 3 zones with separate t-stats, and 3 separate Grundfos 3 spd circs, and an Amtrol indirect DHW with a Taco 007 circ. The current piping setup is not what HTP recommends for the Vision 1 system.

What are some option(s) for an add on control(s), to give DHW priority, individual control of each zone circ with t-stat which also starts the burner and boiler circ on any of the zone calls for heat or DHW. I would also like ODR. I was looking at zone controller/switching relays, either the Grundfos UPZC-4/6, or the Taco SR506, but this only gets me part of it. Can I run a higher temp for the DHW if it has priority over a lower temp heating zone, or what is a practical minimum temp to use and still maintain DHW?.

Not opposed to multiple controls to meet these goals if possible, but trying to keep compatibility, functionality and ease of use and install reasonable for this particular boiler.

Mike

Unknown

Vision 1.

Snap a picture and post.

How is it setup.

I would go with Taco zone control and Vision 1 and repipe the domestic hot water coil location and increase it to 1" with a larger circulator.

This will ensure you get priority and outdoor reset. It should cost less than most other options as well.

Good luck,
Joe

JAL Co. Plumbing & Heating
East Windsor, NJ

Unknown

Other Post.

I see your other post. Give me a call I sent you an e-mail with the information. I should be able to help.

tom_49

munchkin

Mike,

How about the Tekmar 260 (maybe a 270)w/ Sr506 for real simplicity. Will do ODR and DHW priority. Or you could re-pipe DHW and use vision 1.

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Frank_63

Munchkin control stategy

I will post some pics. I will see what it takes to re-pipe and possibly go with the Vision 1. The DHW is ¾” and set up as just another loop off the secondary. If I do re-pipe will the current Taco 007 for the DHW provide the required flow through the boiler, since the boiler circ is off, or should I increase to 1” even though the DHW is ¾? I will see if I can get the pressure drop through the DHW. The primary boiler loop is currently 1 ¼” with a TACO 007. One of the zone control switching relays will give me DHW priority, but will any of the add on ODRs give me 180 degree temps for the DHW if the running heating temp is say 95 or 120 because of the ODR. I know the Vision 1 will do that. Just seeing if something else will work with out re-piping or using a whole series of controls. I’m not without heat or hot water so I’ll do it right. Thanks for the help. Mike

Denny Reardon_3

munchkin

why not pipe the boiler as Munckin recomends Primary-Secondary. Take the inderect off the seconday circit (high Temp) and the heating zones off the primary circits (low temp).
The Vision control will allow this and is complete with an out door reset control. you'll still need a circulator relay but you wont need priority as its built into the vision one control.
I beleve the 925 control is an older control. You may have to add the vision one package. The newer boilers come with the vision contol built in.
If yo use the Thermister on the inderect you can crank up the hot water temp to say 165 and with a Anti Scald valve, adjust the domestic water output to around 120. with an 80,000 btu boiler it will give you the most hot water.

Ted G

I agree, why not re-pipe using a Vision 1 diagram.

Frank_63

Munchkin control strategy

Attached are some pictures. I have others or can get more if someone needs to see something. I looked at the recommended piping for the Vision 1. It specs a heat trap, is this needed to keep the heat from migrating up the pipe during the DHW cycle or is it to keep induced flows from occurring? I assume that during a heat cycle the flows in the boiler supply loop will take the path of least resistance and no flow will go through the DHW. Space is a little tight in my current setup. If needed I’ll have to repipe a heat trap and add a check valve to meet the Vision 1.
The original piping plan was per HTP but not the Vision 1. I have separate air and dirt separators. Using the Vision 1 piping plan no water is flowing through them except during the heating season, which depending on heating load is only a percentage of the total boiler run time. Is this an issue? The hope is that there are no leaks which require make up water, but isn’t part of the good design to constantly purge air and dirt from the system? Just trying to grasp all the concepts.

I know HTP is pretty adamant about their piping plan. Why wouldn’t the Vision 1 system work like I currently have it piped? On a DHW call for heat the heating zone circulators shut down if they were running, the DHW circ runs, and is this case the boiler circ also runs, the boiler output is say 160 degrees on whatever is needed for fast regeneration. In this case two circs running versus only one, as in the Vision 1. Everything is still P/S. Once the DHW call is satisfied, the heating zones resume running if the Tstat still calls for heat, at a water temp based on the ODR control to the boiler. If there is some residual water at a higher temp in the boiler or P/S piping system it will soon be tempered if it is lower. Is this even feasible, or can the Vision 1 system be wired this way, or am I seriously missing something? Thanks to all for the help. Mike

Denny Reardon_3

the way you have it piped will work. However if its piped the way with the vision 1 control you will get a 2 temp system.
on a call for heat the doestic pump will be off. the primary and seconday pumps will run as needed. This will be low temp based on the out door reset set up.

On a call for hot water the primary pumps will still run as needed however the seconday pump will shut off and the domestic pump will run on priority as the prority is built into the vision 1 control (high temp).
the vision one control also allows for post perging of the talk of resigual heat.
I set up all my inderects to produce the max hot water in the tank (165) and install an anti scald valve to temper the hot water out put to around 120 so the customer get the most hot water.
I'm not sure about the heat trap on the supply side of the heating. My guess is to prevent migration. The same as if it were use on the supply side of a domestic water heater.

What about this? HTP wants the heating circulators on the supply. And they want the inderect pump on the supply feeding into the inderect. all is good.
But they want the secondary pump on the return feeding into the boiler. proberbly due to the presure drops of the coils.
If we install circulators on the vertical return off the header feeding into the boiler (pointing down)and the pump has an internal float check. Will thr float check work?
What about the weight of the water forcing the check valve to leak by. it this a possibility?

Frank_63

Munchkin Control Strategy

Denny,

I guess I’m trying to see the advantage and if it will work if I don’t change the piping to the Vision 1 plan, but use the Vision 1 control to get me the other benefits, two temps, post purge and ODR. In the Vision 1 they take the DHW indirect pipe off right near the boiler and return it between the boiler circ pump and the boiler return inlet, nothing goes through the P/S. During a call for DHW they only have one pump running through the indirect and boiler. My current piping setup would have two pumps running and going through the P/S. . I want the Taco 007 on the boiler return side to run on any heating zone or DHW call for heat. This circ does not have any check valve in it or in the piping on the boiler loop, it wouldn’t need it.. I know that with the Vision 1 piping plan the check valve is needed to keep the flow going where it is suppose to. On a DHW call the indirect circ will have priority, the boiler ramps up the temp, and the heating circs are off. On call for heat the indirect circ is off and the heating circ(s) run along with the boiler circ at a temp based on the ODR. There must me some reason they want the piping different for the Vision 1 versus their specs for the non Vision 1, and not just because. Maybe just to reduce the number of running pumps or they are assuming we are using only the Super Stor indirect which is all 1” pipe. With the proper pump they can get all the required flow through the boiler and indirect. Maybe it’s something within the control. Maybe I’m just too thick to see it. Thanks MIke

Unknown

Missing.

I do not know of any priority zone control that will intigrate with the 925 control to give you two temp prority for your domestic.

With the vision sensor installed in the water heater well you will be able to control your DWH with the 925.

If you use an aquastat then you will only engage the DWH pump through your priority control and be stuck with what your system temp is set to.

If you use the Vision 1 with the pipe the way it is now your DWH pump will engage but your system pump will not. Then you will be pulling through your systm pump.

You might be able to wire the system pump to run for the DWH call but now you are talking more controls and a more complicated wire scheme.

Vision 1 with the DWH sup/ret changed would be the least expensive and easiest way to go IMO.

Good Luck,

Joe

Give me a call I think I can explain better on the phone.

Unknown

They have it piped that way...

They have it piped that way to get the hottest water from the boiler direct to the DWH. That, and as you point out you will only be runnig one pump vs the two.

I have not used the new Amtrol but they do claim less pressure drop. So there is a good chance your 3/4 and pump will be fine.

I don't know why they still show the non-vision way in the install book. I have had a few folks who had the Munchkin installed by others call me to install the vision kit. They were not happy to hear the pipe needed to be changed.

nm_2

i have installed numerous T80 munchkins and using Amtrol for indirect heater. 3/4" piping and the 007 taco work fine(providing you are not very far from boiler with the indirect)
I agree that the piping should be redone so that the DHW pump is coming off from the primary loop instead of the secondary loop.
If you install the vision 1 then the boiler is capable of 2 temp settings with the DHW as priority. Water temp to heat the indirect is factory set at 185 degrees and the heating temp is user programmable. The munchkin will stop the heating pump and start the DHW pump (also the Munchkin with vision 1 will run the indirect for a specified time) it is a programmable feature on the munchkin to allow the indirect to run for let's say 30 minutes and go back to heating mode for 30 minutes and then come back to satisfy the DHW demand.

clammy

Idea

How about you install a taco multi circ panel with prority and install your vision one ,tie your dhw pump wires to a 110 volt coil of a double pole relay .Then wire one set of of the contactor to your existing boiler pump,use the other set of contact to make your existing dhw pump which you have set to priority on your sr504 pump controller ,with out thinking to deeply or draw it out i believe you will be able to use the post pump run time also and keep both pumps running and of course you will have to replace your existing tank sensor or aquastat and install the htp dhw sensor in the existing well of your tank ,for a relay i would use a easy RIB relay they are double pole model with varying coil voltage ,peace and good luck clammy nice install to boot

Frank_63

Munchkin Control Strategy

Either way I will go with the Vision 1 system since it’s designed for this boiler and looks like the simplest way. At the start that is what I was trying to see if it was possible to use the Vision 1 and not change the piping plan. The indirect and heat loops would all go through the P/S. After reading the other posts and looking at what I would need to change it’s probably easiest to set it up as HTP recommends. The indirect loop is pulled right off close to the boiler with the hottest water, only one pump is running during the DHW heat call, and for the summer months a lot less 11/4” copper is heated in the mechanical room. It looks like all I have to do is put in a tee and a check valve in the boiler return side, and change some pipe directions, the indirect loop is short and easy to insulate. I still need the multi circ panel. I will see how it all works out. Thanks for all the help. Learning more every day. Mike