Kat's 24250 250 Watt 4"x 5" Universal Hot Pad Heater

Xringer · 03-11-10, 09:22 PM

I was looking at fish tank heaters and saw 300 watt heaters were being
used to keep 100 gallon (uninsulated) tanks warm..

So, I stumbled across this interesting product. It's 250 watts (853 BTUh) $40.

It seems to be designed to be epoxied to the oil pan (on a flat part) of an engine or other item that you want to keep warm..

I have this 76 gallon boiler that has a nice flat spot on the top..

So, I'm thinking about sticking one of these gadgets on the old boiler and burning
up a bit more electricity each month, to run a little test.

The test goal would be to see if a mere 250 watts would be enough power
to reduce the amount of oil used for hot water (and heating too),
by increasing the time between oil-burner cycles.

The heater would be left on during daylight hours (6 hours total), using a timer to simulate PV wattage.

In the spring (or when I get the heat pump working), when the heat is shut off, and oil is only burned for hot water needs,
I should be able to judge how much PV wattage is needed for my PVHW project..

In case you haven't seen my crazy PVHW idea, here's the link..
http://ecorenovator.org/forum/solar-...eat-water.html

These postings are also related to my Solar Tracking posts at:
http://ecorenovator.org/forum/projec...r-project.html
Since the plan is to use the solar tracking mount loaded with some PV
to use as a power source for hot-water heating.

Comments please:

Cheers,
Rich

gasstingy · 03-12-10, 07:44 AM

Do you have access to the top of the water tank, or just the cabinet? If it's just the cabinet, I doubt you'd see much if any difference. Even on the tank itself, since heat rises, I think the results would be disappointing if you adhere the pad to the top. If you have access to the bottom of the storage tank, it might give measurable results.

Xringer · 03-12-10, 08:29 AM

The sheet metal lid will lift right off. Inside on the left, is a bolted on hatch.
Installed in the hatch cover is two 1/2" fittings for the copper domestic HW coil.

Last year, I noticed the red sheet metal cover was warm to the touch,
so I layered in some insulation under the lid. It's cold on top now.

My thinking is to apply the heating pad very close to the domestic coil.
Right on top if I can find the space. And then cover the pad well with
some good insulation /w a foil reflector surface facing the pad.

I do not want the pad down low on the boiler, where it will try to heat all 76 gallons.
But if it could keep the upper 20 or 30 gallons warmer, those would be nice.

Up at the top is where the coil is and where the Aquastat temperature sensor is located.
If it's warm enough around the Aquastat, the burner won't come on so much.

Hey, I found a picture!

That little round red thing just to the right of the oil burner is an Electric heating element. (I have three of those 2" holes).

The boiler is an OT series 35.
Woodboilers.com &raquo Discontinued Boiler Infor

Xringer · 03-12-10, 09:51 AM

The hot water coil hatch takes up all the flat space on the left side.
So, the right side will have to do. I think the water jacket is 2 or 3 inches
thick on the right side (above the solid fuel fire box), so it should work pretty well.

The air bleeder insures that water is in direct contact with that right surface.
But, looking at the cup shape of the hatch, makes me thing it might have
an air-pocket inside..

I wonder how well that 250 watt Kats pad would work with 108 VDC from two Kaneka 54V PV panels?? (110 watts each).

Kaneka Thin Film Solar Panel 110w

NiHaoMike · 03-12-10, 10:03 PM

It looks like the furnace can also burn wood. Couldn't you plant a lot of trees in your backyard?

Xringer · 03-12-10, 11:04 PM

It can burn wood and junk mail..

It also has the coal grate installed.
I always keep some firewood on hand. (I was just cutting some the other day).
Just in case we ever have a power outage that last too long..
But, I don't try to burn solid fuel as a rule. It's too messy and too much work.

Starting in a few minutes, (at midnight) my little power monitor
will start logging the daily electrical and oil use of the boiler.

In a week, I should have a mild-weather benchmark to compare
with heating days using the Kat's 250 Watt heater.
If we get some stable weather, without storms and over-cast, I should be
able to compare similar Degree-Days, with and without the E-Heating pad.

If I find that 250 watts (853 BTUh) makes a decent difference in
oil usage, I will likely go forward with my PV-HW plan.

If I can see no real oil savings, I'll double up. And install one more 250 watt heater,
(more insulation) and start testing again..

Xringer · 03-20-10, 02:24 PM

Here it is.. 250 watts of heat.. the cold resistance is 55.7 ohms.

I'll plug in the Kill-a-Watt once I get it installed..

Xringer · 03-20-10, 04:04 PM

It's showing 246 watts on the Kill-a-Watt meter.

Step 1, take it down to the bare metal.

Step 2, peel off the backing and stick it on the boiler.

Step 3, adding insulation over the pad was deleted pretty quickly, due to softening of the foam part of the insulation.

Xringer · 03-29-10, 07:28 PM

We are back on the Sanyo ASHP for home heating and I was able to run a quick test this afternoon.

On electrical power alone, no oil..

14:45 Boiler at 148F & probe at 110F
18:05 Boiler at 152F & probe at 126F

I guess the insulation works better at lower temperatures..

This 4 degree increase in temperature in 3.33 hours, means we might be
able to get a 6 to 8 degree gain on sunny days, with 250 watts of PV panels.

I don't fully understand what's up with the probe temp jumping up 16 deg,
but I think the 'pad' radiates a lot of heat into the top section of the boiler
where it's trapped. I'm starting to think I need a better heating element.
Maybe like those on regular electric hot water heaters..

03-11-10, 09:22 PM	#1
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Kat's 24250 250 Watt 4"x 5" Universal Hot Pad Heater I was looking at fish tank heaters and saw 300 watt heaters were being used to keep 100 gallon (uninsulated) tanks warm.. So, I stumbled across this interesting product. It's 250 watts (853 BTUh) $40. It seems to be designed to be epoxied to the oil pan (on a flat part) of an engine or other item that you want to keep warm.. I have this 76 gallon boiler that has a nice flat spot on the top.. So, I'm thinking about sticking one of these gadgets on the old boiler and burning up a bit more electricity each month, to run a little test. The test goal would be to see if a mere 250 watts would be enough power to reduce the amount of oil used for hot water (and heating too), by increasing the time between oil-burner cycles. The heater would be left on during daylight hours (6 hours total), using a timer to simulate PV wattage. In the spring (or when I get the heat pump working), when the heat is shut off, and oil is only burned for hot water needs, I should be able to judge how much PV wattage is needed for my PVHW project.. In case you haven't seen my crazy PVHW idea, here's the link.. http://ecorenovator.org/forum/solar-...eat-water.html These postings are also related to my Solar Tracking posts at: http://ecorenovator.org/forum/projec...r-project.html Since the plan is to use the solar tracking mount loaded with some PV to use as a power source for hot-water heating. Comments please: Cheers, Rich Last edited by Xringer; 03-12-10 at 08:00 PM..

03-12-10, 08:29 AM	#3
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	The sheet metal lid will lift right off. Inside on the left, is a bolted on hatch. Installed in the hatch cover is two 1/2" fittings for the copper domestic HW coil. Last year, I noticed the red sheet metal cover was warm to the touch, so I layered in some insulation under the lid. It's cold on top now. My thinking is to apply the heating pad very close to the domestic coil. Right on top if I can find the space. And then cover the pad well with some good insulation /w a foil reflector surface facing the pad. I do not want the pad down low on the boiler, where it will try to heat all 76 gallons. But if it could keep the upper 20 or 30 gallons warmer, those would be nice. Up at the top is where the coil is and where the Aquastat temperature sensor is located. If it's warm enough around the Aquastat, the burner won't come on so much. Hey, I found a picture! That little round red thing just to the right of the oil burner is an Electric heating element. (I have three of those 2" holes). The boiler is an OT series 35. Woodboilers.com &raquo Discontinued Boiler Infor Last edited by Xringer; 03-12-10 at 09:24 AM.. Reason: add-on

03-12-10, 09:51 AM	#4
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	The hatch The hot water coil hatch takes up all the flat space on the left side. So, the right side will have to do. I think the water jacket is 2 or 3 inches thick on the right side (above the solid fuel fire box), so it should work pretty well. The air bleeder insures that water is in direct contact with that right surface. But, looking at the cup shape of the hatch, makes me thing it might have an air-pocket inside.. I wonder how well that 250 watt Kats pad would work with 108 VDC from two Kaneka 54V PV panels?? (110 watts each). Kaneka Thin Film Solar Panel 110w

03-12-10, 10:03 PM	#5
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	It looks like the furnace can also burn wood. Couldn't you plant a lot of trees in your backyard? __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...

03-20-10, 04:04 PM	#8
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	It's showing 246 watts on the Kill-a-Watt meter. Step 1, take it down to the bare metal. Step 2, peel off the backing and stick it on the boiler. Step 3, adding insulation over the pad was deleted pretty quickly, due to softening of the foam part of the insulation. Last edited by Xringer; 03-21-10 at 08:02 PM.. Reason: mod made

03-12-10, 07:44 AM	#2
gasstingy Journeyman EcoRenovator Join Date: Feb 2010 Location: Arab, AL Posts: 491 Thanks: 109 Thanked 49 Times in 43 Posts	Do you have access to the top of the water tank, or just the cabinet? If it's just the cabinet, I doubt you'd see much if any difference. Even on the tank itself, since heat rises, I think the results would be disappointing if you adhere the pad to the top. If you have access to the bottom of the storage tank, it might give measurable results.

03-12-10, 11:04 PM	#6
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	It can burn wood and junk mail.. It also has the coal grate installed. I always keep some firewood on hand. (I was just cutting some the other day). Just in case we ever have a power outage that last too long.. But, I don't try to burn solid fuel as a rule. It's too messy and too much work. Starting in a few minutes, (at midnight) my little power monitor will start logging the daily electrical and oil use of the boiler. In a week, I should have a mild-weather benchmark to compare with heating days using the Kat's 250 Watt heater. If we get some stable weather, without storms and over-cast, I should be able to compare similar Degree-Days, with and without the E-Heating pad. If I find that 250 watts (853 BTUh) makes a decent difference in oil usage, I will likely go forward with my PV-HW plan. If I can see no real oil savings, I'll double up. And install one more 250 watt heater, (more insulation) and start testing again..

03-20-10, 02:24 PM	#7
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	Here it is.. 250 watts of heat.. the cold resistance is 55.7 ohms. I'll plug in the Kill-a-Watt once I get it installed..

03-29-10, 07:28 PM	#9
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	We are back on the Sanyo ASHP for home heating and I was able to run a quick test this afternoon. On electrical power alone, no oil.. 14:45 Boiler at 148F & probe at 110F 18:05 Boiler at 152F & probe at 126F I guess the insulation works better at lower temperatures.. This 4 degree increase in temperature in 3.33 hours, means we might be able to get a 6 to 8 degree gain on sunny days, with 250 watts of PV panels. I don't fully understand what's up with the probe temp jumping up 16 deg, but I think the 'pad' radiates a lot of heat into the top section of the boiler where it's trapped. I'm starting to think I need a better heating element. Maybe like those on regular electric hot water heaters..