Controls For Circulater ...

[weimedog]

So want to have a heat sensor on the stove with a control to have the circulator turn off if the stove temps drops below a certain temp, or conversely turn on if the temp gets up to a certain point. Most controls.....work the opposite ie. turn on a boiler when the temp drops to a point. So would be a temp sensor and control with the ability to turn on and off a 115v system, on if the measured temp goes above a certain point, off if the temp drop below. What do you suggest? 

[E Yoder]

A ranco temp control could be wired to do that. But there's the risk of freezing things or stratifying with no circulation.

[weimedog]

A ranco temp control could be wired to do that. But there's the risk of freezing things or stratifying with no circulation.

Wood stove with stainless tubing inside. And the stove is inside. Basically the current oil burning furnace is like a 30 gallon heat reservoir. And the idea was to add heat to the furnace with the wood stove in addition to the oil fired furnace and use the existing thermostats and circulators to pump heat around the house. Ended up just turning off the oil furnace as the wood stove made enough heat to take care of all but the coldest days...a complete success. The coil to the hot water heater on the other hand isn't because if we aren't around to feed that fire, the hot water heater adds heat to the system as the temps in that line tend to cool the water in that system. SO
Want a way to shut the curculators off when the wood stove drops below a certain temp for both the hot water system and the loop to the base board/oil furnace. Have a way to measure the temp of the stove at some location and if it drops below a certain number shut off the circulators so I'm not heating the house with the hot water heater. Conversely when the fire is started and the temps in the stove raise to a point where it's reasonable to turn on the circulators have that switch turn them on. The typical system for heating systems works exactly the opposite. Typical system has an external thermostat react to dropping temps to turn on the circulators vs. shutting them off. Hence the dilemma...

I guess another way to think of it is like a cooling system for the wood stove, when the wood stove gets beyond a certain temp, turn those circulators on to carry the heat away! And when the stove is cold, don't pump the cooling system and save on electricity.

So if a ranco system can be made to control the circulators to turn on when the fire gets hot......vs the other way around I'm interested!

[hedgerow]

Weimedog
That's nice thing about ranco temp controls they can be set up for heating or cooling. You can buy them several different voltage 24 volt or 110 volt or 220 volt. Pull up the install instructions on the net and you will see all the ways it can be set up.   I have several on my Garn boiler system. One to turn pumps on and off for my domestic hot water one runs my floor heat pumps in my shop and one that runs a air handler with a coil in it to turn it and the pumps that feed it on and off. 

[Hilltop366]

If i am reading this right you could add a low temp cutoff control to the stove to oil boiler circulator to turn the circulator off when there is a low fire.

Now the circulator will shut off when the stove temp is low so the oil burner can be left on for backup, the temp settings on the cut-off and boiler will have to be adjusted to get the right effect.

Other things that would be good to have in the system is a over heat (high temp) control To prevent boiling over in your oil boiler, (usually turns on the heat circulator to dump access heat or can add a different dump zone elsewhere) as well as a power failure safe guard in the form of a normally closed zone valve that is above the boiler and feeds a rad that is mounted in a way that will gravity feed.

I have the simple mechanical aquastats for my wood boiler, the ones I have seen are usually Honeywell or White-Rodgers. There are also surface mount hydronic temperature controls that may be easier to use in this application but I am not sure if it would be the right thing to use, probably would be best to ask a pro about that.

Search for low temp aquastat as well as surface mount hydronic temperature controls.

[E Yoder]

Taping the probe from a Ranco control on the pipe with metal tape and insulating around it has got me within a couple degrees. Close enough for anything I've needed. I'm assuming that would work for other controls also.

[weimedog]

Which model of these controls should I be looking for? To handle the amperage required to fire those circulators?

[Hilltop366]

Not sure of the amp draw of you circulators or how many. My circulator is less than 1 amp. The amp rating for the mechanical controls I have used are 7 to 10 amps @ 110 v.