The Thermostatically Controlled Cathouse Heating System!
Here is the resident tomcat that has adopted us (he mooches at other houses too!) the last few years.
Since we've spent a few hundred on several vet visits for him I guess this project isn't too expensive! heh
Here are the main components of the system! In the upper left is a Heat ONLY thermostat, $11 bucks.
To the right of that is a small electric heater, $12. It is a Holmes HFH110 which has overheat protection but does
NOT have tip-over shut off protection, which is what I wanted since I needed to mount this sideways on the cathouse!
The heater has 2 settings, low and high and is rated at 1500 watts. I am running it at the low setting, not sure what
the wattage is at that setting, I will have to check when I get a chance. Actually I would have liked a much lower power unit
that would have put out a lower level of heat.
The clear tupperware tub on the right will be to cover the heater and keep the rain off of it, $5.
In the middle is a 120v to 24v transformer, actually it's a doorbell transformer, $14, that has 3 different voltage settings
you can choose from, all of these parts came from Lowes by the way!
The electric box at the bottom is a plastic disconnect box, also about $11.
$11. heat only thermostat.
$12. small portable heater.
$14. 24v doorbell transformer.
$11. Water resistant Disconnect box.
$ 5. clear tupperware storage box without lid.
$00. Scavenged scrap thermostat wire.
$00. Scavenged 2 relays rated at 30 amps with 24v coils. (I think the heater is max out at 16 amps)
$00. Scavenged electrical cord with 3rd ground plug on it.
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$53. Total!
If you wanted the schematic then here it is, I've color coded the voltages different for 120v and 24v
...of course you don't have to use 2 relays like I did.
The power cord and the transformer both have green ground wires so I put them on the rectangle ground bar in the middle
Here is a shot of the top half of the dog house, er cat house, with the hole cut for the heater to blow through and
the heater cover is screwed to the back. I went back with a few bolts and nuts to hold it well though.
Here is a shot of the back with the heater cover. You can see I used a grease pencil to mark where the tupperware will fit.
Here I have cut a slot below the heater so that the heater, once it has the tupperware cover on it, can suck return air
from inside the cathouse and heat it up and put it back in again.
Here is a test fit of the tupperware over the heater and return air slot, I still have to cut the bottom to fit the lid.
Here it is raggedly cut with a scroll drill bit
Test fit after being cut, pretty good!
Ok, cover back of and screwing down the electric box holding the transformer, two relays and has the power cord that will
go to the wall going in it, the thermostat wire going in it and the power cord from the heater going in it
This is the electric box with the cover and disconnect removed. I've test fitted 2 relays rated at 30 amps in the bottom.
I had to move them up because I put them too close to the holes at the bottom where the wires go. If your wondering why I used
two relays it's because if one of them sticks closed for some reason the other will still open and the heater won't run constantly.
Here is the box all wired up.
From one of the 24v wires on the transformer I hooked a thermostat wire that goes to the termostat,
..we'll call it the red wire. The red wire ties to one of the two termials on the thermostat, then we tie the white
white on to the thermostat. Back in the box the white wire ties to a red wire under the orange nut cap and
goes to the first 24v coil on the right relay, there is a second red wire on the same spot on the relay that jumps
over to the top coil of the second relay.
The bottom coils on both relays have a jumper between them (the blue/purple looking wire) and it also ties back
to the 24v transformer on the other tap completing the 24 volt loop
I've tied all of the white, or neutral, 120v wires and put them under one of the big lugs at the top left
The black, or hot, coming from the power cord will go under a right lug up there with another wire tied to it that
goes to one of the main high voltage contacts on the first relay. There is a jumper from the second tap on the first relay going over
to the first HV tap on the second relay and the second hv tap on the seond relay gets the hot wire going to the heater!
Screwing on the cover
Mounting the thermostat inside the cathouse, it's coming together now!
Since it is a heat only thermostat I only need two wires!
T-Stat installed!
...and we're good to go! Yipee!
Here it is out on the porch and installed! You can see I have put duct tape over the seeams on the top of the
tupperware cover. The porch is covered but sometimes rain shoots in from the sides pretty good. The reason that I
used tape right now is I don't want to put caulk on there till it's warm out and he won't be using the thing and I
won't have to worry about him getting doped up on caulk fumes! hehe I'll have to duckt tape over the outlet until
I can get a drop cover for it.
Nice inside shot. We have a (I think) cedar chip filled pillow on the bottom and some old sheets in there too.
...with his light installed, I replaced the regular bulb with a florescent bulb that doesn't put out any heat since
he has a real heater now and doesn't need the light for heat. Strange cat won't go in there without a light though!
Well here you go, one bachelor cat pimping in style!! :)
**Afternote: I've gone back and drilled two quarter size holes in the bottom of the tupperware
tub (bottom meaning facing the ground). The reason being is that while it works great it is really putting
out air that is TOO HOT for the small space and could get the cat too hot or sick or run him out which is
counter productive. I didn't check the temp on the air coming out but put my hand in there close to the middle at
the bottom and it was uncomfortable. After drilling the two holes hurridly before going to work it seems better.
I might drill another one or two though, will have to check it again.
This is why I said I would have rather had a much lower wattage unit. They had a little 150watt thing (I think) at
Sharper Image store but they wanted like $40 for the thing and I would have had to disable the tilt-over shut
off mechanism and while I don't mind doing that I'm cheap! heh. Another option would be to shorten the heating
coil element but that's more work than it's worth I think. (well for lazy me anyways)
Anyway it seems to warm up slower and at a better temp now!
