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Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 5648
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have mulitple kwb heaters,which have thermos that go to 90

Customer Question

i have mulitple kwb king heaters,which have thermos that go to 90 degs. i need to get to 100 degs, for my yoga place. is there anyway to get them to go hotter.
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

Are the units controlled currently by a remote thermostat on wall?

Customer: replied 1 year ago.
no they are controled by a switch.
Customer: replied 1 year ago.
they are 240 volts 30 amp and have a thermo on unit which goes to 90 degs. they turn on and off by a switch on the wall.
Expert:  airheatman replied 1 year ago.

What I am asking is if the thermostat that controls them is mounted on wall with low voltage control wire ran between units and themostat? I understand the units operate on 230 volts, but there are 2 ways to control. One breaks the 230v through thermostat and other breaks 24v to control to activate heat. Do you have a model on existing thermostat?

Customer: replied 1 year ago.
kbp2006 3mp king electric
Customer: replied 1 year ago.
30 amp from box thru switch to unit.
Customer: replied 1 year ago.
thermo on unit. can i bypass unit to use wall thermo
Expert:  airheatman replied 1 year ago.

Sine the thermostat is in unit and max setting is 90 degrees, I suspect you may have limits built into the unit that will shut it down even if thermostat was bypassed.I am going to open this to other experts who may have more input on a solution for you.

I have opted out of the question to see if perhaps other experts may have more information and can assist.Please do not rate or reply as that will send question back to my desk.Please stand by to see if another expert can assist further.

Expert:  Phil replied 1 year ago.

Hello, I do not have a manual on those units, However it is almost certain that the high temperature limit safety cut out switches operate in the 150 to 180F range or a lot hotter. You will have that protection untouched no matter what we do to bypass the existing 90F thermostat that is built into the units.

If you want to have me draw up a wiring diagram so that you can control. so they shut off at 100F measured at the ceiling let me know and I will do that for you,

If do this so that temperature is measured 50 inches above the floor, then we risk having the ceiling units run closer to the high temperature safety cut off switch presets (those are not adjustable and should not be adjusted either)

Let me know what you think about that, we can go from there. If you wish to proceed on that basis, send me a photo of the heaters taken from about 20 feet away and from as far above the floor as possible so that I can see how far they are mounted from the ceiling and what the hangers look like... I will also need a well focused photo of the wiring diagram glued inside the electrical service panel on the heaters.

Customer: replied 1 year ago.
please. but i can not get you those pictures until first thing in the morning. how much more will it cost. how do i get it to u and when can u get back to me. thank you
Customer: replied 1 year ago.
give me about 30 min and i will get that stuff right to you.
Expert:  Phil replied 1 year ago.

Hello again,

I can quote you a price in the $50 range after I see the wiring diagram so that I can be sure if it can be done or not. If it can be done, in my book it will be quite safe enough because all of the safety controls will be left in tact, but the manufacturer who will have to comply with his insurance company would no doubt *not approve any changes to the controls at all, so it would be at your risk.

It will take me about 2 hours to locate the components needed and create a drawing for you.

I can wait up tonight for the diagram, but might have to do the drawing in the morning.

Customer: replied 1 year ago.
one picture
Expert:  Phil replied 1 year ago.

Thanks, I need a photo of the wiring diagram glued to one of the heaters (if the heaters are all identical)

it will be glued to the inside of the electrical service panel of the heater... possibly on the back side of the unit... the photo needs to be taken from straight on, well lit, close up, and very well focused.

We can go from there.

Expert:  Phil replied 1 year ago.

I will also call the factory tomorrow morning and see what I can get.

Expert:  Phil replied 1 year ago.

There is another issue, a big one, I notice that the room has no ceiling and that the roof is in the 20 to 25' range above the floor.

In order to get 100F on the floor, you will find that the air near the roof will end up getting hotter than 140F or so... that will cause the light fixtures to over heat, and also increase your electric bill by 300 to 500%... in short it will not be viable to provide a 100F room unless it has an 8 or 9 foot ceiling, the lower the better,

We need to discuss that.

Expert:  Phil replied 1 year ago.

There is another issue, a big one, I notice that the room has no ceiling and that the roof is in the 20 to 25' range above the floor.

In order to get 100F on the floor, you will find that the air near the roof will end up getting hotter than 140F or so... that will cause the light fixtures to over heat, and also increase your electric bill by 300 to 500%... in short it will not be viable to provide a 100F room unless it has an 8 or 9 foot ceiling, the lower the better,

We need to discuss that.

Customer: replied 1 year ago.
all heaters have a fan right above them that blows down and goes on and off with heater. i didnt have an 8 ft ladder to get to the heater so it will have to be tomorrow for the wireing diagram vBulletin sorry.
Expert:  Phil replied 1 year ago.

Hello again, I will take an extensive look at that, however even with fans, the hottest air will float to the roof... so the roof will still get to 140F or warmer.

A battery of ceiling fans mounted about 20 Inches below the roof will mitigate the problem down to perhaps 120F at the roof. At the very least you will need some high mounted fans.

Beyond that, roof insulation is an issue if the roof is not insulated very well you will most likely need many more heaters in the winter... in the summer a hot roof will actually help heat the building.

What most people do not realize is how the electric company charges for power, You end up paying more than the base rate, 10 cents per KW or whatever... there are *demand charges* and tiered pricing charges.... the utility company figures if they have to stand by to produce whatever your 15 minute peak usage is, that they have the right to charge you a 40 or 50% surcharge (there is legislation on that). Its a much bigger issue in total than you might realize, I can spend a few hours filling you in those details... the end result will be a decision your part most likely will be to make a special room with an 8 foot ceiling for the 100F exercises.... that is how it will likely shake out after you understand the scope of the situation.

Meantime tell me how many square feet in the building, what percentage is used for the 100F exercises, and what the winter outside air conditions are.... and what hours per day the 100F conditions are needed.

Beyond this 100F situation is *humidification... in summary its like this, if you heat 20F winter air to 100F the resulting humidity will be well under 5 or 10% (35% or higher is healthy) it will take very significant humidification take the entire building up to 35%.... these cost drop exponentially if you limit the 100F exercises to single room with an 8 foot ceiling.

Other options: Overhead gas fired infra red radiant heaters, these heat people, the furniture and the floor without having to heat the air so much...I am not so sure that this sort of heat will be viable for your application, but I am mentioning it so that we do not forget to consider it.

Here again in summary: Heat rises forcably.. it is displaced by cooler air at floor level, this is a serious consideration in the typical 70F heating design, it becomes a huge problem if you want to heat to 100F at floor level with a 20'+ roof over head.

Let me know about all of the above mentioned details please, we can go from there.

Customer: replied 1 year ago.
okay i will answer in the way they were asked. we have 9 high mounted fans. roof is 12 ft high and very well insulated. he is very aware of electric bill, going to be insane. we are in flagstaff az. class will be in afternoon. most likely 12 to 6 pm. roof is 12ft, fans at 11ft heaters at 10ft. we have a kronos humitifer, bigg enough to keep the hole room to at least 80 per humity.
Customer: replied 1 year ago.
i know it would be crazy to try and keep room to 100. heaters currently put out 90 which keeps room at around 80 deg if we could get the heaters to atleast 100, 105 even better. should put the room to 90, 95 perferbly. thank you for all your help.
Expert:  Phil replied 1 year ago.

Thanks,

http://screencast.com/t/p9AbIQ2c5

At 9 each 5,700 btu heaters you have 52,000 btu's of heating, that is what goes into the average small 1,200 square foot home in order to heat it to 72F on a zero degree F day..... those are going to be a long shot at getting the room to 90F in cold weather, but will easily do it on days when it is over 60F outside.... to get over 80 or 90F in cold weather you need more heating capacity.

Tell me please if you have natural gas in the area, it will not be a bad idea to supplement with one of those... let me know about all that, we can go from there.

Customer: replied 1 year ago.
no gas. should we add more, or some portableables for the floor. next yoga shop he is going with enerjoy. just not an option with grand opening in a week. maybe retro at later date. its around 1000 sq ft
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** stay with the existing heaters if the space is only 1,000 sq ft... you can add another few heaters later if required.

I need the wire size that is pulled to each heater in order to determine the maximum heat setting I can use... you can read me the numbers stamped into the end of each breaker (at the main breaker panel, hopefully 30) if its only 20 we will have to run the heaters at less than their full capacity.

Expert:  Phil replied 1 year ago.

Hello again, here are a list of the issues.

You will need 30 amp breakers and size 10 copper awg wire to allow the heaters to operate at their peak output.. you will need the peak output to achieve the 90F-100F range... there is a good chance you have that wiring but I need to verify it.

100 deg F wall thermostats rated at 30 amps are not on the market that I can find so far.. many others have been looking for them as well.. if I can find those we will have a solution. (limited see note on use in Yoga Studio's below)

If I cannot find a wall thermostat King Electric staff suggested bypassing the existing thermostat and turning them on and off at the breaker panel... they also said that in a yoga studio with its several ON OFF cycles a day..... that shortens the life of their heaters which were not intended for use that way.

I cannot say that I like that idea very much at all, because if you forget to turn the heaters off they will heat up the building to 150 to 180F or so until they go off on their internal high temperature safety cut out switches. That would be quick, cheap and easy however.

A proper solution if I cannot find 30 amp rated thermostats, would be a Honeywell zone control system with a 30 amp rated relay for each heater, all that mounted in a big box next to the existing electric panel, and controlled by a single 24 volt wall thermostat in the studio. (cost will be in the several thousand dollar range, I can design that for you if you like).

Let me know what you think, we can go from there.