Tough one to figure out...

Harman

besides that how does it look? anything jump out at you?

hot_rod

And the extra sep, HX, etc.

I sell a bit of leftover stuff like that on Craigslist

Zman

The piping is a solid plan. I don't like that many circulators but some do and it sounds like they have been purchased and delivered.

On the controls, the I series valves will work just fine. Run your outdoor sensor and do a reset, great.

On the boilers, you want to stage them based on their ability to maintain temp rather than the amount of time they have been running.The right controls to do equal run time and auto rotate are not that expensive. Here is one for 2 single stage boilers. http://www.tekmarcontrols.com/products/hvac-systems/261.html

I think you are missing the design intent of radiant. The idea is to provide constant even heat. It is kind of the opposite of forced air. You want the radiant to run almost continuously during cold weather. I really don't think you will need the forced air heat. If the owner insists, use a 2 stage thermostat and activate the forced air if the room temp falls behind by 2 or 3 degrees. That will make things heat up quickly if they turn down the heat and give them a backup. You may need an isolation relay to make the furnace and boiler play nice on the same t-stat.

Harman

Will that tekmar 261 do dhw priority? I have done radiant, but mostly normally with a mod con, and when not a mod con a logitmatic control on a g115 or 215, I try to do the same equipment all the time, I have what imo gives me good reliability and longevity for a decent price and I still with it... Also when I do radiant systems I use mixing valves, zone valves, and thermal actuators... this system had to be $15K in materials...

Zman

To do DHW priority, you have to turn off all the heating circs. Might be easier to do that with a zone switching relay. This one with an expansion added on would do. https://www.supplyhouse.com/Taco-SR506-EXP-4-6-Zone-Switching-Relay-w-Priority?gclid=EAIaIQobChMIgrKT7Muf2gIVW57ACh0p-ALQEAYYAyABEgJsjfD_BwE

SuperJ

I agree with Hot Rod, sell the pumps and other unused stuff on the local classifieds (or post them here). Tell the HO it will offset your bill a bit (but don't make any promises on what they'll go for).
I bet they are worth enough combined to by one or two delta p pumps (assuming they are basically new).

Zman

Do I dare ask what model circ they purchased?
That may be your deciding factor.

Harman

the newer style bumble bees, viridian, but not the new viridians...

what delta p do you recomend, I have a few alpha 2s on the shelf at the shop...

Harman

I will buy the materials they need and throw the extra stuff on the shelf, I know Ill use the extra hydro separator, the fphx may sit around a while since I have only really used them on outdoor wood boilers and havent done one of them in a solid 3 years, the circs I wouldnt worry too much about I go through 007's I can throw them virdians on the truck and sell them at a discount to the customers who would be interested, but I would honestly rather not do that...

Harman

Ok, so I have a solid plan, I will have the manual j done this week, I am going to pipe it as the last picture shows, I will use pair switching relay with priority, a tekmar 261 for boiler staging, and I am going to switch to the grundfoss 15-55 (I believe thats the right number) alphas...

Unless there is a pump that will work better I am not aware of?

hot_rod

All the pump brands offer ∆P options, pick a color.

Grundfos probably has the longest track record, made in Fresno, Ca if that matters. They have a Alpha 1 and 2 available if you don't need all the features of the 2.

https://us.grundfos.com/alpha.html

Harman

I get them 15-55s for $150 each by the case from RE micheals when they have their spring and fall sales. I have never used taco delta p circs, just their t's the old bumble bees, and they did the job...


and thinking about the zone controls I will actually need a 5 and 4 zone to get 8 with priority, or a 4 and 3 with a master for the dhw... Ill figure the best cost and look at some of their wiring requirements...

SuperJ

Your plan sounds good, the home owner should be a happy customer.

Nothing wrong with the Alpha2 for most residential sized applications. For the Panel rads it will do best on AutoAdapt (Grundfos' special sauce Proportional Pressure Mode). Don't forget to install the checkvalve since you have a bunch of pumps and piping branches.

One other idea is to pipe your basement baseboard circuit off the panel rad delta P pump as well, (as long as you add a TRV/zone valve, and the temperatures are compatible). I like TRVs since they are a modulating pure mech control that can be placed away from the mech room without having to home run wires and such. If you have a lot of baseboard in series you might want to use a zone valve or set the TRV to a higher temp so it's more of a high limit than a modulating control. This will give you the outdoor reset function from the mixing valves and result in longer run times with even heat since the water won't be so hot.

hot_rod

In some areas there are rebate programs for upgrading to ECM technology, check into that.

Caleffi also has some relay boxes with unique features. With 3 relay outputs and priority status selection you can customize to many unique applications.

Harman

Does anyone have experience with the pc702, I may forgo the 261 and wire it as seen here on page 24, seems to be exactly what I need...

https://s3.amazonaws.com/s3.supplyhouse.com/manuals/1351151766524/85275_PROD_FILE.pdf

SuperJ

No experience with the PC702.

For the TRV'd panel rads and maybe your infloor, you might want to just jumper the thermostat input on your relay board. So the pump and mixing valves are continuously enabled unless there is a DHW call, or WWSD.

SuperJ

I think your pump is backwards for your DHW tank, I'm not sure about the way your indirect is piped. You may want it on closely spaced Tee's on the hot supply pipe if it's on the primary side of the separate. Or you may want it on the load side of the HS.

If you draw/return off the primary (into the supply and return pipes respectively) side of the separator (as drawn) maybe you don't need to stop the zone heating pumps since it will get first dibbs on the hot water (flow would bypass the separator thru the DHW tank)? The zone heating would just recirc thru the separator if there is no left over primary flow for them. Am I crazy? That being said I don't think a previously messed job is the place to experiment, it just needs to work properly for the HO.

I'm curious what the other guys think about the DHW piping in the drawing?

Zman

The PC 702 is a rebadged Tekmar. I would double check that it will rotate lead lag. If so, that would work.

Harman

yes super you are correct, my supply is actually backwards, I used ms paint for this and didnt bother to use red and blue lines, but I am thinking come off the supply side before the HS with a circ pumping into the tank and return it in the return line after both boilers... You think this would be better off with closely spaced tees, I normally dont do indirects that way, I normally do a normal loop from the supply and return...
Have I been doing that wrong, I havent had any trouble with them and been doing it that was for a long time, I can't remember why I never did them with closely spaced tees, and the only other way I ever did it was on the opposite side of the HS, but that was usually because of tank placement, if it was another 30 feet of pipping to get to the other side of the HS I would just pipe it on the load side...

Zman, it does look like it rotates lead lag, I think that 702 will do all I want it to, it costs a bit less, and it plugs directly into the zone controls from taco (I normally use argo, but for this job I will go taco except for the pumps)...

So the control actually looks like it will be a bit easier than I first expected, I will use the 2 stage thermostat to control the furnace aux/backup, I will use the 702 for the staging and the exp taco switching relays for the zoning, and that should get all the controlling done for around $1500 (including t stats) which is not bad at all IMO..

SuperJ

Something to consider with the indirect tank pipe is the location of the sensor for the 702. I would normally put the system sensor for your 702 on the load side supply pipe of the HS, but if your DHW loop is pulling off before that, the temperature reading won't be valid. In DHW priority mode the temperatures will be at their highest so you want good temperature feedback so the boilers don't start cycling on their own safeties.
As drawn you will have to put the sensor on the supply pipe between the boilers and the indirect take off.

hot_rod

I'd probably move the indirect connection after the hydro sep. Use the separation function and air removal better. Treat it as another "load" but on a priority function.

If you use TRVs on panel rads, just plug that ∆P circulator into a 120V outlet. Leave it powered 24/7 so exercise functions can be utilized.

SuperJ

hot rod said:

I'd probably move the indirect connection after the hydro sep. Use the separation function and air removal better. Treat it as another "load" but on a priority function.

If you use TRVs on panel rads, just plug that ∆P circulator into a 120V outlet. Leave it powered 24/7 so exercise functions can be utilized.

That's what I was thinking but wasn't confident enough to say it . To tweak Hot Rod's suggestion, you could get the DHW priority function to work by killing the demand signal to the mix valves during a DHW priority call and leaving the delta P running as HR suggested.

hot_rod

When you pipe multiple boilers into a hydro sep, this header pipes need to be sized for the combined flow of everything you connect. So if those two boilers need 7 gpm, size the headers for 14 gpm, 1-1/4" pipe. If you add or take off other connections size the headers according to the total possible gpm.

Harman

I was going to do the piping 1 1/4" and use 1" mixing valves and 3/4" for each zone.

You guys have me thinking about the indirect piping now ,you are correct the filtering and air elimination will not function directly to it, BUT it will be in the system obviously, what are the pros and cons of doing it each way, I would rather fix this now when it is a drawing...

Harman

and it that drawing I have the supply and returns from the boiler backwards, supply should be going to the top pipe and return to the bottom

Harman

so heres another quick drawing, this one I didnt add the baseboard loop, as I think I succeeded in talking them into more radiant panels in the basement and getting rid of the base board all together..

Zman

You are probably spitting hairs on the piping at this point.
As for the mixing valve and pipe sizing, Once you determine the design flow rate through the valve, select a valve with a Cv rating roughly equal to that flow rate. For piping, shoot for pipe size which gives you 4 ft/sec for general piping and reverse/return headers. 2 ft/sec is better for low loss headers. You can google charts to convert ft/sec to GPM.

HomerJSmith

"Problem is theres 3 cases of delta t circs there, what do I do with them," Put them on Ebay, buy them with your labor at a discount and stock them, or maybe your wholesale distributor will let you put up a sign offering them to other contractors.

Look, do the job right, 'hot rods' correct. 10 pumps? The HO were snookered and that's regrettable, but if they can afford to do it right, do it right.

You are constrained in that the heat emitters are already installed and your stuck with it. A design load calculation will only allow for a water temperature adjustment in the radiant sys and whether you can meet the load requirements.
Floor coverings are going to make a difference.

Dollars to donuts, you are going to have 2 different temperatures in the radiant sys, one for infloor and one for the panels.
I would scrap the circulators and go with 2 Taco I-series mixing valves with ODR and 2 sets of 3 port manifolds with possibly a ECM pump for the infloor and a ECM for the Panels. The Panel radiators are piped with PEX? The ECM pumps would eliminate any relays and give you better electricity to water efficiency.

The infloor manifold would have 3 thermal actuators for zoning to 3 thermostats. The panel radiator manifold would just have shut off valves. You are going to have to have balancing valves on the infloor circuits and panels to control the flow. So make sure the manifolds have them.

The Taco I-series goes before the pumps and the pumps goes before the manifolds.

You are going to need a controller with sensors to sequence the boilers, especially since another boiler may be added for sno melt and you have to give priority to the indirect W/H. You are going to need flow checks and I wonder about the return water from the indirect creating condensation in the boilers. but the hydro-separator may prevent that. The boiler operating temperature would be about 180 deg to satisfy the indirect and the baseboards.

Everything else is straight forward.

Harman

Zman said:

You are probably spitting hairs on the piping at this point.
As for the mixing valve and pipe sizing, Once you determine the design flow rate through the valve, select a valve with a Cv rating roughly equal to that flow rate. For piping, shoot for pipe size which gives you 4 ft/sec for general piping and reverse/return headers. 2 ft/sec is better for low loss headers. You can google charts to convert ft/sec to GPM.

I think you are right, how its plumbed in the picture will work well for the boiler room, and I I think this setup will work well, my only concern is cold returns from tank, BUT maybe moving the tanks piping to the other side of the HS will help this, what do you think?

Keep dhw before HS or install is on the system side like a heat zone?

SuperJ

Placement depends on the budget an level of rework you're able to undertake. After the HS is ideal, but there are ways of making it technically work before.

Upsides to leaving it as is:
-less rework for you
-less $$$ for HO
-maybe... built in DHW priority due to getting first dibbs on hot water pre HS. (But your relay box will do that anyways)
Downsides:
-Compromised system sensor placement (this is probably this biggest downside IMHO). Ideally you want the HS discharge temp to be maintained, but having the tank on the primary side forces you to control off your primary temp. So if secondary side flow exceeds primary flow, the supply will be diluted with return water reducing it's temperature. this reduction will be invisible to the boiler staging controller, and may hamper effective heating in high demand scenarios.
-Loss of multiple Hydraulic Seperator functions during DHW priority calls
-Non standard install may be questioned by others (you'll have to defend it saying it works to other contractors who may advise the HO it's installed "wrong".)

Things that are basically the same either way:
-pumping
-relay and controls setup (except for sensor placement).
-Boiler protection strategy

What I would do
Pipe it after the HS unless there are some major hurdles.

Boiler Protection Idea for indirect
Depending on which delta T pump you have, you can set it up with boiler protection turned on. It can slow down to keep the return temp up. This could work at least for the indirect circuit with the right sensor placement.

hot_rod

We often show it on the boiler side with mod cons, on the distribution side with conventional, really it works in either location.

Will you have two boilers run to cover a DHW priority call? if so, depending on the indirect HX capacity and how you pipe and pump it, that load with the 120K you have available should recover quickly. Hard to predict their DHW use patterns.

Zman

Personally, I would put it after the separator.
The way the heat exchangers are sized in most indirects, both boilers will fire for most of a DHW call. It will happen automatically as the boiler supply temp will drop and the controller will fire the lag boiler.

hot_rod

One of 3 conditions exists in a hydraulic separator.

If both flow rates match A & B side, 100% flow goes to the load.
If not you get blending either to the load, or return to the boiler. Ideally the hottest supply to the load, and the coolest to the boiler will be the best transfer on both sides.

The math to solve these equations is in Idronics 15. But don't make yourself crazy over this piece of the rehab

Harman

OK, so I met with them today (went there and gathered all my manual J data, not that I can change the tubing in their floor, but at least I will know the load, for BTU / GPM) and they madde a decision to get rid of the baseboard in the basement and go with more radiant panels, they also decided to go with heated towel racks in the 3 bathrooms, FUN... lol

I am going to redraw it with the indirect on the other side of the HS...

Harman

I am skeptical that the amount of buderus wall panels they have in some rooms are going to be enough btu's to keep the rooms warm...

They have a 12'x15' bedroom with 7.5' tall ceilings, you have to get on a design day 75 degree rise, and they have 2- 12"24" model 21's in there.... off the top of my head I am thinking that room is an 8000 btu load... no way them panels are making that kind of energy...

Zman

The way I usually do this is to put together a spread sheet with the BTU loss and the available square footage for each room. I then compare those numbers to the BTU output of the radiant panel (floor in your case) at different supply water temps. Usually you will find that one temp will work well for most of the in-floor heat.
Then take that design water temp and size your panel radiators to meet the needs of their spaces. The manufactures have published formulas or charts that will tell you how they will perform at the reduced water temps.

Zman

Those 2 radiators will put out 3,676 Btu/hrs with 180 degree supply water. At 140 degree supply water they produce 1.940 Btu/hrs.
3,676/180 sq ft =20.4 Btu/ft. If your heat loss calc for that space ends up around 20 Btu's, you will know that the radiators were sized for 180 degree water on your design day.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Buderus - 3-42436 - Application Guide.pdf

SuperJ

> @Harman said:
> I am skeptical that the amount of buderus wall panels they have in some rooms are going to be enough btu's to keep the rooms warm...
>
> They have a 12'x15' bedroom with 7.5' tall ceilings, you have to get on a design day 75 degree rise, and they have 2- 12"24" model 21's in there.... off the top of my head I am thinking that room is an 8000 btu load... no way them panels are making that kind of energy...

Since you’ve sold them on panel rads for the basement. You could upgrade the upstairs ones and move the existing ones to the lower load areas in the basement. Upgrade to model 22s for the same footprint if necessary.

Tinman

Lots of really good input. I second the idea of using the Taco PC-702. Its plug and play w Taco relays and I find them to be very reliable. I also use Taco"s i-Series mixing valves quite a bit. Don't overpump the system. Use zome valves with delta P pumps. Somewhat repetitive but that's how I'd attack it.

Zman

SuperJ said:

> @Harman said:

> I am skeptical that the amount of buderus wall panels they have in some rooms are going to be enough btu's to keep the rooms warm...

>

> They have a 12'x15' bedroom with 7.5' tall ceilings, you have to get on a design day 75 degree rise, and they have 2- 12"24" model 21's in there.... off the top of my head I am thinking that room is an 8000 btu load... no way them panels are making that kind of energy...



Since you’ve sold them on panel rads for the basement. You could upgrade the upstairs ones and move the existing ones to the lower load areas in the basement. Upgrade to model 22s for the same footprint if necessary.

@SuperJ Excellent idea...