boiler protection

Paul S_3

I need to provide boiler protection from flue gas condensation...boiler is cast iron atmospheric gas fired....system is 2 pipe hot water system....one zone ...cannot use buffer tank due to budget and really dont want to change piping to primary\secondary....i was looking at the Taco bumblebee has a setpoint mode which can be used for boiler protection from condensation.....good idea? I also looked into the Caleffi boiler protection valve, which is about same price as bumblebee, but in the valve literature it shows buffer tank or p/s pumping, can the valve be piped without p/s piping ?any recommendations Paul S

Weezbo

depends ...

do you need pumped injection, system set point controlled by pass ,boiler by pass ,



re mix on the return comes in many flavors ...



*~//: )

Paul S_3

bypass

What i have now is 2 pipe system...apt building for 12 families... i want to use constant circ with wwsd....and outdoor reset...no tstat....paul s....no injection pumping

Weezbo

ok so goin large..lol

well ,

maybe a one inch taco sweat two way ,

with set point control off the circ , pumping away ,

to the supply side of the constant circ ,

from the boiler circ to the return of the boiler ,



underneath that connection of the bypass ,

would be a paco temp gauge a few pipe diameters closer to the boiler to show you what is returning to the boiler ..



you could put the sensor above it ..... for the set point controller I series S one inch...

3/4" might be just as good , you'd have to do the math as they say ..









and do not forget drop the return (Of the set point by pass) off deep to the return ..



usually , a tToff after the boiler circ ,

across and down by 90 ,

to the valve,

with another drop by 90 ,

to behind the return,

down,

by 90 horizontal to a T into the return ,

short nipple,

connect sensor with some zip ties ,

on the lower side of that ,

on the boiler return ,

a T looking forward with a gauge screwed into it ...



looks sharp and always gives you options ..

Harvey Ramer

Weezbo

more info on the thread labled thermostat.

Paul S_3

is

This what you mean? Paul s

hot_rod

mix valve

is a simple non electric solution. No need to have a buffer or p/s. The pump needs to be sized for the flow required, and pressure drop presented.



The large 280 ThermoMix has a 14 cv, so 14 gpm with a 1 psi drop across the valve.



If you go this route remember the 18° differential. A 140° valve plus 18° = 158° to completely close off the bypass port.



On my wood boiler I ended up with the 115° sensor, so 133° close off.



The ThermoMix valves are typically used with wood or biomass boilers, so that is why you see a buffer piped in.



Nathan White up in Alaska uses them to protect oil fired boilers from extended cold returns.

Paul S_3

Bob

I ordered the 'boiler protection valve from caleffi...I will be using it in the setup to the right (right side drawing)...I believe it's the standard 140f cartridge...when you say 18f diff...you mean at or below 140f the valve is fully opened allowing all of the water from supply to return and at 158f the valve is fully closed allowing no water to bypass into return?....is this differential adjustable? And can this hurt a job of something isn't considered thanks Paul s

hot_rod

here is the info

it is very simple to change the temperature sensing element. Install the valve, give it a try, if you need a lower element I will get one to you.



What you may find is the boiler ramps up to near its high limit, say 180F before the bypass port closes off 100%. The lower temperature sensor allows lower temperature bypass, shut down.



When it is up and running measure the temperature at the return to the boiler, and the supply temperature. With a bare hand, carefully feel when the bypass is shut off. That pipe will cool down when it shuts 100%.



It may work fine, mine likes the lower temperature because the inducer fan on my wood gasification boiler started to rev down before I had full flow to the system.





http://www.caleffi.us/it_IT/Instruction_sheets/NA10292/NA10292.pdf

Paul S_3

BPV

How come in the Caleffi BPV literature it shows all piping schematics with the pump on return?You can see on the right drawing above that my pump is on supply ....thanks Paul S

hot_rod

usually

you pull flow through a mix valve not pump into. You only need one pump if it is a basic S&R piped system. Just as you would pipe a common cast iron, single temperature boiler



The boiler pump runs the mixer circuit and flows the system. That pump needs to be sized for the load, correct GPM required, to move the energy load.



When you cold start 100% of the flow from the boiler returns to the boiler. As the boiler warms the valve allows some flow to the system, increasing as the return warms. eventually the bypass closes 100% and all flow goes to the distribution.

Weezbo

ahere is an idea ,Paul

take the time to read this , it is explaing the concept in use on one of our most used methods of conveyance ...

.http://www.google.com/patents/US6712028



i have a reason for that , it speaks of the same things we are speaking about here with the parts arranged a little differently ,

i have another link ,



Take time to re read the idea of by pass in the firsst link and then in the second link pay some attention to discussion of pumps ..



this will widen your understanding of these various types of controlled by passes and what they do .



Weezbo.



..

..

http://en.wikipedia.org/wiki/Radiator_(engine_cooling)

Paul S_3

return

So in my situation I have to put pump on return to pull flow through?....thanks for help Paul S

Weezbo

the simplicity of the control,

that Hot Rod is talking about is a very beautiful thing , it is somewhat confusing if you have never seen one or installed one , the first time you install one you might even think it is broken or just must be a bad one from the factory ...: ))



here too is where gauges help folks out a bit ...



it is not going to seem like it is happening at first ,



you might think that the heat is "Stuck " in the boiler : )))



trust this one though be patient things will flow..



and make some huge difference in protecting your boiler and managing the heat distribution side .



These have been around a long time , when you first see the box in your hands you think this is one heavy chunk of iron , then when you hook it up you are like really anxious for it to "GO"

lol...



have fun with your new discovery..

Greenwood

Alternative Mixing Valves

Caleffi makes good equipment, but expensive.  We utilize ESBE VTCX511 mixing valves which offers the same protection while working with varying thermostats (130F, 140F, etc.).  We use the 140F thermostat for our wood boiler product offering complete return water protection for our customers.

Paul S_3

thanks

For all your help....and sorry for constantly repeating this but IM having trouble understanding this BPV with the setup I have already....I know that I should be pulling through the valve similar to a mixing valve in radiant heating? And of that's the case them I have to put the pump on the return.....to pull hot supply water into return...as of now I have the pump on the supply aside of boiler pumping away from expansion tank....can I keep the pump there with a tee in front of pump bull of tee bypassing water into BPV which is on the return and run of that tee in series with system supply....out do I have to put pump on return pulling water through valve? Thanks Paul s

hot_rod

either location

I spoke with the engineers that designed our valve the pump can in fact be on the supply. It' more about the circ, they like to see them in the cooler return fluid, as some wood boilers tend to overshoot temperatures under no power conditions.



Also to Greenwoods point, that is a fine brand he promotes, but a bit of an apples to orange comparisons, for starts one is iron bodied, the other brass, quality, support, etc.