homemade boiler protection valve

[cumminstinkerer]

has anyone out there built a boiler return protection, similar to a danfoss, using a 140 degree thermostat for a marine application GM small block? I have a machinist friend that will build the tee and flanges to make it all work for a case of beer and the thermostat will only cost me 25 bucks, I honestly cannot see any reason that a setup like that would not work just fine, plus I can have him install whatever size threaded fittings I need on it. I am open to criticism so fire away.

 

[Eureka]

I think it would work. That’s pretty much what the inventor of the thermostatic valve did.
I just forked over the $199 for the Caleffi 280.
It isn’t too complicated looking
.
But I’m not sure it’d be worth it since I don’t see much to improve on.

 

[maple1]

My LK810 has something internal that will allow convection flow through it from storage in the event the power goes out and the circ stops running.

 

[salecker]

Hi Happy holidays.
How are things going with your boiler?
What do you see as the advantage of the unit you are proposing ,and a near boiler protection pump?
Thanks Thomas

 

[cumminstinkerer]

@salecker whith the current near boiler circ and loop when the main circ fires it will drop return temps down too low, then main shuts off, near starts, repeat cycle a hundred times. I am thinking that if I put my proposed valve in at the base of the near boiler loop, keep the pump, I could then spread the on/off of the near boiler out, allowing it to continue to run even when the main is running with the thermostat throttling the incoming return from storage to get a more even return temp into the boiler. I have played around with a ball valve in the return before the bypass loop, using it to throttle return and it improves temp swings greatly, the only drawback this method is that as storage warms up you have to continually adjust the ball to keep increasing return flow, makes for a bit of a pain for others to run. My thought is that the thermostat would act much like the ball valve only be automatic, making it so that if I am gone my mom or my wife can run things much easier and even if I am around I don't have to go mess with the valve every hour or so to keep temps correct.

 

[salecker]

Thanks...
I need to find a way to get and capture the data from mine to see how it actually works.
When i built my system,it seemed to work very good.Not having anything to compare it too and being self employed i just ran with what i had.
I keep hoping to have the time to tweak some more performance out of it,but life keeps happening and i have no problems heating the house even though a month of -40 last winter so doing any tweaking keeps dropping to the bottom of the list.

 

[Woodman1]

I have an older design danfoss three way valve for boiler protection. I use a 160 degree automotive style thermostat in it. My boiler typically yields a 20-30 degree temperature rise through the boiler during full burn. It works out perfect to give me a steady 180-190 degree water as I am recharging storage while supplying heat to the house and hot water.

 

[maple1]

Personally I'm not sure I'd try this. Unless you have a design thought up that would let the acting part of the stat see the mixed water? I think it would have to, to constantly work right? Also thinking of (at least some) Danfoss users needing to use a throttling valve on the bypass loop. And allowing flow from storage bottom if the circ stops (power outage). Just sounds like some niggling design details to get right or it won't work right - i.e. not as simple as it might seem?

 

[Woodman1]

Yes. The sensing bulb of the thermostat has to be placed so it is in contact with the water from the bypass loop from the boiler. I have a ball valve (throttling valve) plumbed in the bypass loop. It’s set at about 1/3 closed. I never have to touch it. I think this is because my storage is close to the boiler, plumbed with 1.5” pipe. I assume that is why the system is balanced so easily and it don’t have to mess with the throttling valve.

 

[Jeff S]

I have no doubt that one could be fabricated to work but seeing this would be one of a kind unit I would definitely want it designed so you could easily change the thermostat in case of failure and have a spare on hand.

Mixing valves may seem expensive but the protection they offer is priceless. I paid 6K for the boiler I install 13 years ago, the couple hundred dollars invested in the mixing valve seems like a great investment then and now.

 

[cumminstinkerer]

one of the nice things about my idea is the thermostat is an off the shelf 140 degree small bloc chevy, any parts store has them, the rest is simply a little machine work that my buddy can do really easy, have a couple brews with him while he's at it, the end result will be very similar to many of the existing valves, the main difference will be mine will have removable flange with a gasket to replace the stat. I am figuring all told I will have about 30-40 bucks in the whole thing.

 

[Jeff S]

Being able to buy one at any auto store would certainly be a huge convenience. Most people don't realize that the engine in their car is also a mini boiler that is used to heat the people inside and the thermostat that's is being used is performing simulator functions as the one in for boiler protection. Fact is you can an I have drove cars without the thermostat but dont advise it for any legnth of time. Your engine may not last as long and your fuel efficiency will suffer because the engine is more efficient at certain temperatures and when the fluid gets too hot the thermostat will open and let it circulate thru the radiator and the fan will kick on when needed so it doesn't over heat. When temps hit its lower levels the thermostat closes and stops circulating to the radiator. In a perfect world your engine runs in very narrow temperature zone. Your boiler needs to operate in the preferably over 140 degree range but not boiling either.

 

[cumminstinkerer]

@Jeff S you are exactly right, except in the case of the engine the heat is wasted energy unlike our boilers, lol. I was glad to find the small block chevy one since they are so common. As for driving without a Tstat you are right, although certain models will actually overheat without one, Cummins B series 12 valves, Case tractors, John Deere, Cat and I am sure others those just come to mind, the thermostat in those actually blocks off a bypass passage when it opens and without them the engine is stuck in bypass, just like if you don't have a balance valve in the bypass loop on your boiler. I will get some pictures of the finished product when its done, I won't be able to get there until next week as of right now though.