Evaporative cooler thermostat control

[xxsponkyxx]

I have a Breezair Si evap cooler that has basically had the electronic water management and thermostat control system removed (due to a fault) and now operates basically via a standard wall switch. This switches the power to the fan and pump off/on.The cooler works great but i would like some control over temp.Seeing as there is no longer a thermostat to control the cooler...Is it possible to fit a thermostat in place of the wall switch to control temp?
I was given a Honeywell DT200 digital room thermostat that has an on/off function as well as temp setting and it is rated for 24-240v.
Is it as simple as fitting this in place of the wall switch or am i getting my hopes up.
Any help would be fantastic...cheers

[OBBob]

Hi there,

This is what is done for the basic central heaters, so it should be possible. You can by after market thermostats in hardwares ... but for one that also does air con you may need a more specialised place.

You would also need to know what that wall switch is doing, because normally the thermostat would just be a low voltage 'control' signal. It would just tell a bigger switch (or realy) somewhere else to turn on the fan and pump. If your switch is actually directly turing on the fan and pump, you will also need to add the relay ... otherwise it will most likely fry.

[xxsponkyxx]

Thanks OBBob,
My understanding of thermostat controls is basic.I understand that they are a switch but wasnt sure if i could just substitute it for the wall switch.The switch is connected to the mains supply that feeds the cooler and the fan and pump are directly connected to that,so no relayon the cooler itself..i was curious if it would work as the thermostat i have is rated at 240v.inside the controller there is a relay in the circuit board and this seems to connect to the 240v side of the in comming power supply..

[OBBob]

It's not really my area of expertise and a little hard to tell without seeing the whole set up. However 240V is a good start but it is the current rating that you would need to be aware of. Pumps etc. can draw a lot, especially on start up.

In theory it is possible but you might need a sparky to have a look for you??

[Barry_White]

I personally can't see the point of a thermostat control on an evaporative cooler. Once the air is cooled to the maximum of the water laden air it wont make much difference.

Very different to refrigerated air conditioning where you have a return air that is going back through the condenser and being further cooled.

With evaporative the air is sucked into the building and exhausted back out through the windows and doors into the atmosphere.

Just my take on it.

Footnote: I would think that you would need to operate the thermstat through a contactor to take the motor loads

[OBBob]

That's a good point but I was thinking he meant a thermostat to turn it on when it got too hot in side ... rather than turn it off when it got cool enough.

I too am a little surprised that the whole system is currently being run through a wall switch.

[Barry_White]

That's a good point but I was thinking he meant a thermostat to turn it on when it got too hot in side ... rather than turn it off when it got cool enough.

I too am a little surprised that the whole system is currently being run through a wall switch.

I would think that having it turn on when it got hot enough is pointless and not being controlled by a switch. When its hot enough turn it on when its cool enough turn it off.

If you had it turning on when it gets hot and you aren't home that's a waste of power and water and it would just pressurise the house because unless you live out in the bush where you might not lock up your house.

Even refrigerated systems have an on/off switch.

When I was installing them and mind you that was quite few years ago the only controls we had was a separate high and low fan switch and a pump switch so you could just have the fan running to circulate air without running the water pump.

[Skew ChiDAMN!!]

I gotta agree with Barry on this one, to my way of thinking it's not only pointless but is likely to bring out the worst design fault in swampies: condensation.

Unless you leave enough windows open (and, as Barry said, security issues there!) the odds are very good you'll come home one night to find a film of condensate over everything. A case of man-made dew. Not a good thing.

Much better to just turn it on when you need it and off when you don't. Unlike a refrigerative unit, a properly maintained swampy will drop the temp in a matter of minutes (provided it ain't muggy, of course!) even in the hottest of houses. A refrig, of course, needs to be turned on early lest it be overwhelmed...

[Border boy]

I recently did a diy install with a second hand swampy, the unit is about 10 years old but in pretty good knick. It didn't come with a users manual & none could be found on the net. It came with a wall controller that has basic operating instructions inside the cover. I was with you guys in thinking that the unit is either on or off, or by turning the pump off it behaves like a ducted fan. It has an auto setting that I was confused about.Subsequent use revealed that when the auto button is hit, the pump starts without the fan to wet the pads a short time later, the fan starts.. OK I thought, that was all. But there was more. It seems that the contol unit has a thermostat inside. Depending on the setting on the rotary speed control, the pump will turn off when the thermostat senses that a desired temp has been reached. If the temp gets cooler due to outside temp, the fan turns off. These control units are made by an Aussie company called Tekelek, http://www.tekelek.com.au they make them for all the major evap cooler manufacturers . I'm sure if you contacted them, they could give you the info you need.
Cheers.