Only ever owned Coachman Royales. Never had to deal with an electric water heater before in a GMC. I'm getting a massive education on GM installed interiors. Bob Dunahugh
Will my OHM meter reading till me if the heating element is OK in the electric water heater?
- Thread starter Bob Dunahugh
- Start date
> Yes, but you have to know what you are looking for.
>
> Why are you trying to meter it?
My quick in my head calculation says it should be around 8 ohms. Measure right across the element. There is a thermo-switch mounted on the end up
against the tank. It should be 0 ohms unless the tank is very hot. When hot, the switch will open.
If you are checking for a short to ground tripping a GFI that will be more difficult because that short is usually shorted through the water in the
tank. Iyt is easier to just disconnect BOTH hot and neutral and see it the GFI quits tripping.
If the element is bad, buy a 4000 watt 240 volt replacement at Home Depot.
When that one is run at 120 volts, it will draw 1000 watts and should last forever running at 1/2 voltage.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
>
> Why are you trying to meter it?
My quick in my head calculation says it should be around 8 ohms. Measure right across the element. There is a thermo-switch mounted on the end up
against the tank. It should be 0 ohms unless the tank is very hot. When hot, the switch will open.
If you are checking for a short to ground tripping a GFI that will be more difficult because that short is usually shorted through the water in the
tank. Iyt is easier to just disconnect BOTH hot and neutral and see it the GFI quits tripping.
If the element is bad, buy a 4000 watt 240 volt replacement at Home Depot.
When that one is run at 120 volts, it will draw 1000 watts and should last forever running at 1/2 voltage.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
Followed you till the last 2 sentences. Wouldn't you want a 2KW 240V to get 1KW at 120V?
Yes checking for leakage to ground (compromised element) may be hard with the low Voltage of the Ohm setting itself.
--
John Lebetski
Woodstock, IL
77 Eleganza II
Yes checking for leakage to ground (compromised element) may be hard with the low Voltage of the Ohm setting itself.
--
John Lebetski
Woodstock, IL
77 Eleganza II
John,
It would seem logical that 1/2 the voltage would be 1/2 the power, but check ohm's law: P=E squared / R. So power goes up by the voltage squared
divided by resistance. Hence a 240V 4Kw element consumes only 1kw at 120V.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
It would seem logical that 1/2 the voltage would be 1/2 the power, but check ohm's law: P=E squared / R. So power goes up by the voltage squared
divided by resistance. Hence a 240V 4Kw element consumes only 1kw at 120V.
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
Thanks Bruce.
I made the same calculation mistake one time and the power consumption did not work out. Since it was a simple calculation I did it in my head.
After it did not work, Emery Stora pointed the error in my ways and it made sense.
You definitely want a 4000 watt 240 volt element which will consume 1000 watts at 120 VAC.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
I made the same calculation mistake one time and the power consumption did not work out. Since it was a simple calculation I did it in my head.
After it did not work, Emery Stora pointed the error in my ways and it made sense.
You definitely want a 4000 watt 240 volt element which will consume 1000 watts at 120 VAC.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
This GMC was sold to the sec owner in 1985 with 104,000 miles on the clock. This sec owner painted it. And keep it inside. Then took the ENTIOR interior out to refresh EVERYTHING. So it hasn't had any water in it for 33 years. Going to pressure test it with air tonight. If OK. Put water in it to test the water heater. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Friday, August 17, 2018 7:57 PM
To: gmclist
Subject: Will my OHM meter reading till me if the heating element is OK in the electric water heater?
Only ever owned Coachman Royales. Never had to deal with an electric water heater before in a GMC. I'm getting a massive education on GM installed interiors. Bob Dunahugh
________________________________
From: Bob Dunahugh
Sent: Friday, August 17, 2018 7:57 PM
To: gmclist
Subject: Will my OHM meter reading till me if the heating element is OK in the electric water heater?
Only ever owned Coachman Royales. Never had to deal with an electric water heater before in a GMC. I'm getting a massive education on GM installed interiors. Bob Dunahugh
Bob,
With an electric water heater, it is wise to add a timer to shut it OFF. Replace the water heater ON/OFF switch with a wind-up timer similar to those
used on bathroom vent fans. This will make sure the water heater element is OFF except when you have expressly turned it ON.
The big killer to the electric heater element is forgetting to turn OFF the water heater switch and the water level goes down in the heater. Without
the water "load" on the element it overheats and burns out in seconds.
Our regiment is we turn the timer ON to 30-45 minutes when we wake up for showering and washing breakfast dishes. We also turn it ON as we start
making meals or before we intend to take a shower. It only takes 10-15 minutes to have hot water.
JWID
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
With an electric water heater, it is wise to add a timer to shut it OFF. Replace the water heater ON/OFF switch with a wind-up timer similar to those
used on bathroom vent fans. This will make sure the water heater element is OFF except when you have expressly turned it ON.
The big killer to the electric heater element is forgetting to turn OFF the water heater switch and the water level goes down in the heater. Without
the water "load" on the element it overheats and burns out in seconds.
Our regiment is we turn the timer ON to 30-45 minutes when we wake up for showering and washing breakfast dishes. We also turn it ON as we start
making meals or before we intend to take a shower. It only takes 10-15 minutes to have hot water.
JWID
--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
