piping diagram

Weezbo

and why not use a taco i series S (setpoint) to modulate the return ....? on the by pass...

Don Robertson

Piping

Does anyone have a simple boiler piping diagram for the following application? My customer is adding a zone of RFH.(11,500 btu/hr - quik trak). He has an existing non-condensing oil boiler with standard parallel piping.(I think there is 2 existing hi-temp zones) The RFH will be fed with a simple 3 way thermostatic mixing valve. (Or hopefully a motorized valve w/ reset if we can up sell him.) My customer would prefer to not have to re-pipe everything in primary/secondary. Is there a way we can create a p/s loop off the existing boiler manifold? Any help would be greatly appreciated.

Constantin

You could try a mixing block

Buderus, Taco, and others make them. They allow variable-speed injection and the application may be the right one for this project.

George Peteya_2

Radiant Add-on

Can you post a sketch of the existing near-boiler piping?

rb_6

Schematic

May not be exactly what you're working on but will get you going in the right direction. Keep the tees close together...less than 4 pipe diameters or closer.

Nron_13

nice drawing

> May not be exactly what you're working on but

> will get you going in the right direction. Keep

> the tees close together...less than 4 pipe

> diameters or closer.

Nron_13

nice drawing

> May not be exactly what you're working on but

> will get you going in the right direction. Keep

> the tees close together...less than 4 pipe

> diameters or closer.

Nron_13

nice drawing

Robert can you send me a copy when you have the time . here is a digram with the wirsbo/taco mixing block they work great and have the outdoor reset and supply return sensors built right into them from tekmar , 1 puump is the injection pump and the other is the system pump for your secondary side they work great and are sized up to 100MBH

J.C.A._3

Another option....

Taco i series 3-way. Use the close spaced tees for a seperate zone, and the valve head has all the re-set and end switch goodies built in. Just a thought. Chris

Jed_2

That would be a bit of overkill

> Buderus, Taco, and others make them. They allow

> variable-speed injection and the application may

> be the right one for this project.

Jed_2

That would be a bit of overkill

for this application, Constantin, WRT both price and equipment capacity. RB's nice drawing is great. Some might wonder about RWT with a non-condensing boiler. But, with such a low heat load for the additional zone, it probably won't affect the RWT that much. The Taco Radiant Mixing Block is way overkill for this. But, a Taco 2 or 3-way i-series valve, with an additional small circulator, could be emplyoyed for this, and provide OR and boiler protection. Maybe Joe Matiello would like to chime in on this. I would like to see his piping solution as well. I searched Taco's site for an appropriate piping application, and none jumped out. But, I'm sure there is one.

Jed

rb_6

Consider it

done.

Are you doing some work with DM?

RB

Constantin

Yup...

If the radiant load on the system is low enough not to cause a chronic low return water-temp condition, I agree that Roberts solution is a more cost effective one.

However, in the absence of some modeling via Siggy's HDS, I simply tend to be cautious... The first, rotten waterheater RFH source I have seen documented online with a simple TRV+circulator convinced me that even on the gas side condensing flue gases can do some bad things indeed.

So, while the 11kBTU/hr load may be insignificant in the scope of things, we simply don't know for sure until we understand what the total capacity of the system is, what the emitter temperatures are (inlet vs. outlet), etc. Hence, my preference for variable-speed mixing systems that are designed to protect the boiler, IIRC.

Don Robertson

Thanks

This is exactly what I'm looking for. Thanks for the responses guys. I like the idea of the i-series valve instead of the tmv.

Don Robertson

constantin

I don't know the entire system capacity yet but I agree with you. I think I would want some boiler return protection. At the very least I will encourage a boiler return by-pass. Thanks again for the input.

Don Robertson

Thanks

I think this is perfect for my application. Do you think I should have him pipe in a boiler by-pass as well?

Don Robertson

good idea

That is a good idea. I would think that would provide much better boiler protection than just a by pass w/ a set it and forget it mixing valve.

hr

If the new zone

has to operate when all others are off, that will change how you pipe it. As you know, the new zone will have to fire the boiler and possibly the boiler and/or a primary loop circ.

A rule of thumb is, if the radiant load is less than 1/4 the boiler output, extended condensation should not be an issue. Assuming, of course the boiler is sized for the current and additional load at design?

hot rod

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Don Robertson

piping

That's true. There will be no more primary loop if none of the zones call. Thanks for the tip about the condensation rule of thumb. I help a lot of customers w/ rfh design for a supply house and of all the applications, this one gives me the most trouble. The older version of Wirsbo's CDAM has a piping diagram w/ parallel piping and a mixing valve but I would rather do a primary/sec hybrid of some sort. I'm going to get more specifics on the job and get back to you guys. Does anyone have a hydronic design program? I tried visio but I didn't have all the stencils. I thought I saw a posting recently w/ a new program coming out.