Abnormal high bill

[kwired]

he said something at time about some button on the water heater that had been jimmied so it would not trip... so the house sale would go through probably.. we were young.. new family.. struggling... and I never did get into electric water heater theory... know a lot more about solar water heaters and gas water heaters than electric..lol

They are pretty simple:



Incoming power first goes through a double pole "high limit" which must be manually reset if it's temperature is exceeded. This typically only happens if you get a stuck control thermostat that won't OPEN the circuit to an element when setpoint is reached. When that double pole high limit opens it removes all voltage from everything below it.

After the high limit one leg of the 240 volts goes to a SPDT thermostatically controlled switch located near the upper element. When below set point it closes circuit to the upper element - this to allow it to put heat into the upper portion of the tank - which is where hot water is drawn from, if you heated with the lower element when the tank is full of cool water, it will have to heat more water before the upper portion of the tank is hot, plus incoming cold water enters at the bottom of the tank.

Once the upper thermostat reaches setpoint, it switches - opening the circuit to the upper element and closing circuit to the lower thermostat and element. Lower element never gets a complete circuit as long as upper thermostat is calling for heat - as mentioned we want heat in the top of the tank first where hot water is drawn from. Heat from the lower element will migrate upward and further heat the upper portion of the tank, and because of this the lower element does the majority of the heating unless you have high enough demand that upper portion of tank drops below upper setpoint.

General rule of thumb before even taking any readings, if water is hot but doesn't last as long as it should, either lower element or lower thermostat isn't working, or possibly upper thermostat won't transfer to the lower unit. If voltage is present but no hot water at all, upper element, upper thermostat, or high limit is most likely involved because it must heat the upper portion of tank before it will heat the lower portion, and anything that prevents upper element from functioning will mean no hot water even if lower element and thermostat are in good condition. If upper fails while water is hot, it will continue to be maintained by lower as long as upper portion of tank never drops below setpoint of the upper thermostat, once that happens it will be waiting for high enough temp before transferring back to lower element.

 

[K8MHZ]

They are pretty simple:

View attachment 21343

Incoming power first goes through a double pole "high limit" which must be manually reset if it's temperature is exceeded. This typically only happens if you get a stuck control thermostat that won't OPEN the circuit to an element when setpoint is reached. When that double pole high limit opens it removes all voltage from everything below it.

After the high limit one leg of the 240 volts goes to a SPDT thermostatically controlled switch located near the upper element. When below set point it closes circuit to the upper element - this to allow it to put heat into the upper portion of the tank - which is where hot water is drawn from, if you heated with the lower element when the tank is full of cool water, it will have to heat more water before the upper portion of the tank is hot, plus incoming cold water enters at the bottom of the tank.

Once the upper thermostat reaches setpoint, it switches - opening the circuit to the upper element and closing circuit to the lower thermostat and element. Lower element never gets a complete circuit as long as upper thermostat is calling for heat - as mentioned we want heat in the top of the tank first where hot water is drawn from. Heat from the lower element will migrate upward and further heat the upper portion of the tank, and because of this the lower element does the majority of the heating unless you have high enough demand that upper portion of tank drops below upper setpoint.

General rule of thumb before even taking any readings, if water is hot but doesn't last as long as it should, either lower element or lower thermostat isn't working, or possibly upper thermostat won't transfer to the lower unit. If voltage is present but no hot water at all, upper element, upper thermostat, or high limit is most likely involved because it must heat the upper portion of tank before it will heat the lower portion, and anything that prevents upper element from functioning will mean no hot water even if lower element and thermostat are in good condition. If upper fails while water is hot, it will continue to be maintained by lower as long as upper portion of tank never drops below setpoint of the upper thermostat, once that happens it will be waiting for high enough temp before transferring back to lower element.

Thanks for this. I don't work on these but every once in while and end up having to relearn this simple system.

 

[readydave8]

Frozen condenser is really bad, frozen evaporator is more common though

I suspect that's what I meant, will be more careful in future, thanks!

 

[readydave8]

You would think they notice AC not working correctly with the unit that won't start long before they notice increase in electric bill. Unless maybe it takes several tries and eventually does start, but it would have to be an awful lot of unsuccessful tries I would thing to notice on the billing.

Yes, the house I saw this on recently was one I had listed for sale so uninhabited, found out when I got the light bill

It had something to do with frozen coils so evidently evaporator coils? Compressor would start and build up pressure that couldn't go anywhere so kick off on high limit? Bottom line is A/C guy fixed for $80, so I presume was nothing seriously wrong.

 

[kwired]

Yes, the house I saw this on recently was one I had listed for sale so uninhabited, found out when I got the light bill

It had something to do with frozen coils so evidently evaporator coils? Compressor would start and build up pressure that couldn't go anywhere so kick off on high limit? Bottom line is A/C guy fixed for $80, so I presume was nothing seriously wrong.

Fix could have been as simple as cleaning/replacing filter. Little to no air over coil - leads to what condensation does occur to be able to freeze on the cold coil. If it gets to the point refrigerant isn't soaking up any heat it won't evaporate (or at least not like it should). Should liquid eventually make it all the way to compressor - not good, probably stalling the compressor because liquid won't compress.

 

[growler]

I have a customer who is complaining of an abnormally High electric bill is there any type of issues that would cause this or could it only be caused by high usage.

I'm going out tomorrow to investigate the house has gas heat and hot water and window units as far as the kw usage I'm not sure I would have to see the Bill.

With the gas water heater you can eliminate it as a cause after you make sure it is gas ( I find there are many people that really don't know).

An electric water heater doesn't have to be bad to increase the energy consumption. A leak in the system can cause a lot of problems. A small leak anywhere can waste many gallons of heated water and that cost.

You can probably check on-line with the billing and check recent power usage. Here if you go paperless billing they do keep records.

 

[kwired]

An electric water heater doesn't have to be bad to increase the energy consumption. A leak in the system can cause a lot of problems. A small leak anywhere can waste many gallons of heated water and that cost.

Right, leakage of hot water in the system is more likely to raise energy bill than malfunctioning water heater, thermostat that is stuck closed the biggest exception, but when that happens there is usually other noticeable indications of a problem, hotter than usual water, T&P valve releasing water, high limit is reached and then shuts of water heater altogether.

 

[ggunn]

It had something to do with frozen coils so evidently evaporator coils? Compressor would start and build up pressure that couldn't go anywhere so kick off on high limit?

No, a frozen evaporator coil doesn't block the refrigerant lines, it blocks the air flow over the coil. It causes the compressor to run all the time because the air temp in the building never hits the thermostat set point. It also can load down the air handler fan motor and make it draw more current, possibly to the point where it burns out. The fix may be as simple as improving the condensation drain from the evaporator coil or cleaning the coil to improve air flow.

 

[growler]

Right, leakage of hot water in the system is more likely to raise energy bill than malfunctioning water heater, thermostat that is stuck closed the biggest exception, but when that happens there is usually other noticeable indications of a problem, hotter than usual water, T&P valve releasing water, high limit is reached and then shuts of water heater altogether.

I often find people that don't make the connection between a leaking faucet and a higher utility bill.

When I explain that they have to pay to heat that water no matter where it goes they start to see.

I check my water meter a couple times a year to see if there is water leaking even in places I would not normally see.

 

[ptonsparky]

I rent my shop. The water usage got fairly high even the cost is pretty low.

I mentioned to the LL that my leak was somewhere around 4000 gallons per month and wondered if he could look into it before usage became excessive. He laughed at the excessive.

The village charges for 1000 gal. Often we don’t come close. The village has a chart explaining what one drop per. Minute can do.

 

[drcampbell]

Fix could have been as simple as cleaning/replacing filter. Little to no air over coil ... Should liquid eventually make it all the way to compressor - not good, probably stalling the compressor because liquid won't compress.

A clogged condensate (water) drain can also cause this. The portion of the evaporator coil that's submerged doesn't get any airflow.

Refrigerant doesn't suddenly go from vapor to liquid; it goes through phases -- first small droplets, then large, then a mix of vapor & liquid, then liquid with bubbles, then liquid. When a little bit of liquid refrigerant gets to the compressor, it's called "compressor slugging" and it'll still run. It'll sound like a Diesel engine and it's on the road to ruin, but it won't stop.

 

[ATSman]

Time of Use (TOU)

Time of Use (TOU)

I may have missed it but I'm surprised no one has mentioned TOU metering. I remember out here during the advent of smart meters (9 yrs ago?) people were complaining about how high their utility bills had gotten since the new meters were installed. It took quite a learning curve before we all got used to using the washer/dryer, ironing clothes, vacuuming rugs, etc during off peak hours. And limiting any high energy activity between 12PM and 6PM during the week. Weekends were all off peak ( only 2 tiers.) Now the utility co has revamped their rate schedule with so many different tiers and rates (even weekends) that it takes an Einstein to figure out when to use what and when.
Another thought that comes to mind is a faulty thermostat on the defrost element of a refer. This would probably show up as the refer not cooling the food and was wondering if anyone has experienced this?

 

[Andy1845c]

A neighbour once called me over and asked me what he should do. Something underground was shorting out, and I have to this day, never seen a meter spin so fast. It was before I was in the trade and I never heard what exactly happened, but man it made a horrid sound.

I have also heard of well casing getting a hole in it so the pump never shuts off. Home owner won't usually notice anything for a long time since there is still normal water pressure.

 

[ptonsparky]

A neighbour once called me over and asked me what he should do. Something underground was shorting out, and I have to this day, never seen a meter spin so fast. It was before I was in the trade and I never heard what exactly happened, but man it made a horrid sound.

I have also heard of well casing getting a hole in it so the pump never shuts off. Home owner won't usually notice anything for a long time since there is still normal water pressure.

I found a well leaking like that. Customer complained of higher bill. She had history to verify it. I figured out what the additional load would be, clamped a meter on the wiring until I found the 6 amps.

 

[MAC702]

The most common one I see is the air conditioner being low on Freon. This causes it to run far longer (or continuously), and it's often the biggest load in a residence.

 

[kwired]

A clogged condensate (water) drain can also cause this. The portion of the evaporator coil that's submerged doesn't get any airflow.

Refrigerant doesn't suddenly go from vapor to liquid; it goes through phases -- first small droplets, then large, then a mix of vapor & liquid, then liquid with bubbles, then liquid. When a little bit of liquid refrigerant gets to the compressor, it's called "compressor slugging" and it'll still run. It'll sound like a Diesel engine and it's on the road to ruin, but it won't stop.

Usually on air conditioning there is a condensate catch pan only a few inches deep, if drain is plugged it overflows and makes a big mess instead of submerging a large portion of the coil in the water. What you said may be more common on some commercial refrigeration type equipment - like maybe supermarket display cases.