Lukewarm 'Hot' water ??

["Hi-Viz" Bill]

A couple weeks ago, while at the AL Heartland Rally, the 'Hot' water wasn't!! Without investigating further at the time, I figured the element was bad. We were due to be home in Michigan in a week / 10 days, so I just switched over to gas, all was well, I'd replace the element at home. So, today I remove the element out of the heater and it looks, not new but ok ( it's 3 yrs old ). When I checked it with my ohm meter, I get +- 11 ohms of resistance. I thought I would get a much higher reading, maybe 75 ohms or higher!!

Question: Should I replace the element with a new one?? Or, is the 11 ohm reading about normal, and I have other issues that I need to figure out?? TIA !!

 

[danemayer]

Usually, luke warm water is caused by hot and cold mixing somewhere - outside shower, possibly a check valve problem on the hot out from the water heater, or water heater bypass set incorrectly.

But if it worked ok on propane, it's probably something in the electrical circuit.

Assuming this is a Suburban water heater, where the thermostats for propane and electric are separate, it might be the thermostat on the electric side.

I believe the normal resistance on a Suburban electric element is 14.5 - 17 ohms. So at 11 ohms, maybe it would produce lukewarm water.

If you want to test it, you could put it back together and give it an hour to heat the water. If still lukewarm, check for 120V AC with 1 meter lead on the heating element, and the other lead on a known good ground. Test both of the terminals on the element, again with the other lead on a known good ground.

If after an hour, you have lukewarm water and the voltage is 120V at the heating element, that would tell you the thermostat is still calling for heat, as it should. The element is the problem. If voltage is 0V at the heating element, the thermostat is shutting off at too low a temperature.

If you see values other than 0 or 120V, you could have a problem with the secondary power switch; a black rocker switch in the lower left corner of the water heater. If the switch is causing reduced power to the thermostat and element, you might get lukewarm water.

 

[For20hunter]

We had the same thing happen on our Bighorn and it was the outside shower valves that were on allowing the water to mix. As soon as we turned the valves to the off position we had hot water again.

Rod

 

["Hi-Viz" Bill]

We had the same thing happen on our Bighorn and it was the outside shower valves that were on allowing the water to mix. As soon as we turned the valves to the off position we had hot water again.

Rod

Thanks, Rod !! I know of that issue .. Even tho we don't use the outside faucets, it's the first thing I checked !!

 

[SLO]

Dan is right on the ohms. I don’t usually see 17 ohms but 14.5 is normal. Often see 12 plus ohms though. Elements are cheap though, not hard to replace.


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[cookie]

I wouldn't rely on ohming the heater element.
About six years ago I had the same issue and when I checked the resistance it was good.
I checked all electrical circuits involved and all was good. Scratched my head and went to the store for a new heater element.
That replacement element has been heating water for the past 6 years.
For a $10 element I would just change it out and hope for the best.

Peace
Dave

 

[carl.swoyer]

A couple weeks ago, while at the AL Heartland Rally, the 'Hot' water wasn't!! Without investigating further at the time, I figured the element was bad. We were due to be home in Michigan in a week / 10 days, so I just switched over to gas, all was well, I'd replace the element at home. So, today I remove the element out of the heater and it looks, not new but ok ( it's 3 yrs old ). When I checked it with my ohm meter, I get +- 11 ohms of resistance. I thought I would get a much higher reading, maybe 75 ohms or higher!!

Question: Should I replace the element with a new one?? Or, is the 11 ohm reading about normal, and I have other issues that I need to figure out?? TIA !!

I was wondering if you had checked for 120 volts ac at the element and possibly a bad thermostat on the unit. Other than that I carry a spare and would suggest swapping out the the element.
When I swapp out my heating element I remove the calcium by soaking it in distilled vinegar until clean.

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["Hi-Viz" Bill]

Usually, luke warm water is caused by hot and cold mixing somewhere - outside shower, possibly a check valve problem on the hot out from the water heater, or water heater bypass set incorrectly.

But if it worked ok on propane, it's probably something in the electrical circuit.

Assuming this is a Suburban water heater, where the thermostats for propane and electric are separate, it might be the thermostat on the electric side.

I believe the normal resistance on a Suburban electric element is 14.5 - 17 ohms. So at 11 ohms, maybe it would produce lukewarm water.

If you want to test it, you could put it back together and give it an hour to heat the water. If still lukewarm, check for 120V AC with 1 meter lead on the heating element, and the other lead on a known good ground. Test both of the terminals on the element, again with the other lead on a known good ground.

If after an hour, you have lukewarm water and the voltage is 120V at the heating element, that would tell you the thermostat is still calling for heat, as it should. The element is the problem. If voltage is 0V at the heating element, the thermostat is shutting off at too low a temperature.

If you see values other than 0 or 120V, you could have a problem with the secondary power switch; a black rocker switch in the lower left corner of the water heater. If the switch is causing reduced power to the thermostat and element, you might get lukewarm water.

Hey Dan !! I did put it back together .. After about 1-1/2 hrs, still had lukewarm water !! So, then I tested the voltage on the element terminals .. one terminal had 115.2 V to ground .. the other terminal had 1.0 V to ground !! .. I'm assuming the element is bad, even though the resistance ( 11.0 ohms) 'seems' to be in an acceptable range. Would you concur?? Thanks

Bill C.

 

[cookie]

Hey Dan !! I did put it back together .. After about 1-1/2 hrs, still had lukewarm water !! So, then I tested the voltage on the element terminals .. one terminal had 115.2 V to ground .. the other terminal had 1.0 V to ground !! .. I'm assuming the element is bad, even though the resistance ( 11.0 ohms) 'seems' to be in an acceptable range. Would you concur?? Thanks

Bill C.

Bill, see post #6 of this thread....stop messing with it and get a new element.

Peace
Dave

 

[danemayer]

I'm thinking new element.

 

[CDN]

The element might be opening up as it heats. This would cause luke warm water. Replace it, I carry a spare now since a dealer fried one on me prior to delivery.

 

[SNOKING]

Usually, luke warm water is caused by hot and cold mixing somewhere - outside shower, possibly a check valve problem on the hot out from the water heater, or water heater bypass set incorrectly.

But if it worked ok on propane, it's probably something in the electrical circuit.

Assuming this is a Suburban water heater, where the thermostats for propane and electric are separate, it might be the thermostat on the electric side.

I believe the normal resistance on a Suburban electric element is 14.5 - 17 ohms. So at 11 ohms, maybe it would produce lukewarm water.

If you want to test it, you could put it back together and give it an hour to heat the water. If still lukewarm, check for 120V AC with 1 meter lead on the heating element, and the other lead on a known good ground. Test both of the terminals on the element, again with the other lead on a known good ground.

If after an hour, you have lukewarm water and the voltage is 120V at the heating element, that would tell you the thermostat is still calling for heat, as it should. The element is the problem. If voltage is 0V at the heating element, the thermostat is shutting off at too low a temperature.

If you see values other than 0 or 120V, you could have a problem with the secondary power switch; a black rocker switch in the lower left corner of the water heater. If the switch is causing reduced power to the thermostat and element, you might get lukewarm water.

Dan, a lower resistance would draw more amps and "should" heat the water quicker. 14 ohms would draw around 8.6 amps and 11 ohms would draw around 10.9 amps. Olms law. E=IR or in this cause I=E/R
E is Volts
I is Amps
R is Resistance

I agree, it is time to install a new element. Chris

Chris

 

[Fox]

In 1970 I was first taught V=IR, and we were mostly using electron tubes.
Later on (in 1990) I was told E=IR, and semiconductors were being integraded in large scale.

Now its all just a pleasant memory.

 

[SNOKING]

In 1970 I was first taught V=IR, and we were mostly using electron tubes.
Later on (in 1990) I was told E=IR, and semiconductors were being integraded in large scale.

Now its all just a pleasant memory.

I was ahead of you. USCG Electronics A school for 6 months in 1965, right out of boot camp. Chris

 

[Fox]

I will blame cheap whiskey for my throwing this discussion off track - care to join me?

For an estimated $10 I'd just throw a new element at it, then pour another drink and wait.

 

[wdk450]

Just a hint for anyone testing water temperatures. Test temperature at the source, the water heater, before it can get diluted by bypass valves and the outside shower. CAREFULLY (wear heavy rubber gloves?) lift the valve lever on the overpressure valve on the water heater to get a direct heated water sample. It will probably spray hot water all over the place while it is open, so again, be careful!

 

[Aprilc19]

We are only getting lukewarm water with electric & LP gas . Any suggestions on what to do? I'm tired of taking almost cold showers!

 

[danemayer]

We are only getting lukewarm water with electric & LP gas . Any suggestions on what to do? I'm tired of taking almost cold showers!

Hi Aprilc19,

The two common causes of lukewarm water are 1) the knobs on the outside shower are ON, allowing hot and cold water to mix and 2) if you have a 3 valve water heater bypass, the crossover could be open.