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10-21-2016, 06:46 AM
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#1
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Senior Member
Join Date: Feb 2014
Location: MD
Posts: 3,856
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Hot water heater pulling high amps
Just wanted to see if anyone has experienced this and what the fix was. My brother in law is camping with his 2014 Jayco 264bh. Three times the 30amp breaker tripped at the pedestal with just the ac and water heater on. Mentioned it to a campground worker who advised maintenance would come out. The assumption was it was the pedestal. Thought to look and PI EMS was showing 28-30 amps being pulled with just the ac and water heater on. So now we realized it wasn't the pedestal. BIL turned off the water heater and just the ac was pulling 6-7 amps. Turn water heater back on and back 28-30 amps being pulled.
Why is water heater pulling so much? Could a bad heating element cause this? If not what could be? This camper has never had an issue since being bought new in early 2014 and I know this isn't normal. Thanks for any help.
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2017 JayFlight 28BHBE
2014 JayFlight Swift 264BH (Sold)
2007 GMC 2500 Sierra Classic Crew Cab LBZ Duramax / 6spd Allison
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10-21-2016, 07:01 AM
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#2
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Senior Member
Join Date: Apr 2016
Location: SW Washington
Posts: 1,024
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Low Voltage at the pedestal.
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2009 F350 CC LB 4WD
2017 Jayco 355MBQS
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10-21-2016, 07:05 AM
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#3
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Senior Member
Join Date: May 2015
Location: Campbell Hall
Posts: 2,835
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First, you test procedure is flawed. The A/C should have been switched off when checking the water heater's load. The A/C compressor could be cycling, throwing your load testing off.
If the water heater was drawing too much power from a faulty heating element, the RV's own 15A breaker for that circuit would trip, unless it's faulty as well, then you'd have a burned-up RV.
Get behind the water heater and check it's rating. If it is 1500 watts or better, then 12-14 amp draw would be normal.
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TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!
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10-21-2016, 07:41 AM
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#4
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Senior Member
Join Date: Feb 2014
Location: MD
Posts: 3,856
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Hot water heater pulling high amps
Rusty, low voltage at pedestal will cause something like this? Mike will have him try again with just the hot water heater. Didn't think about the water heaters own breaker.
Thanks for the help. Luckily we've never really had an issue with our Jayco's.
__________________
2017 JayFlight 28BHBE
2014 JayFlight Swift 264BH (Sold)
2007 GMC 2500 Sierra Classic Crew Cab LBZ Duramax / 6spd Allison
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10-21-2016, 08:19 AM
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#5
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Senior Member
Join Date: Aug 2011
Location: Missouri City, The Republic of Texas
Posts: 5,063
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Quote:
Originally Posted by Rustysocket
Low Voltage at the pedestal.
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I think the PI EMS would shut the power off. "That's what it does."
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Cheers,
T_
2013 F-350 CC SB 2WD 6.7PS
2013 Eagle Premier 351 RLTS
-SOLD- 2012 X23B
-SOLD- 2003 Ford Expedition 5.4, Bilstein shocks
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10-21-2016, 08:41 AM
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#6
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Senior Member
Join Date: Aug 2015
Location: Albany, OR
Posts: 692
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Quote:
Originally Posted by SouthCo
Rusty, low voltage at pedestal will cause something like this? Mike will have him try again with just the hot water heater. Didn't think about the water heaters own breaker.
Thanks for the help. Luckily we've never really had an issue with our Jayco's.
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10-12 amps would not be unusual for a water heater on electric. If I remember correctly they are about 1500 watts. In your case, you are saying it is drawing 20amps, which seems high, but without knowing the model/wattage, it is hard to say.
Regarding voltage. Low (within reason) voltage would not normally cause a water heater to draw more current, it would simply cause it not to heat as well on electricity. Now something like a 120VAC motor, yes, low voltage will cause higher than normal current draw.
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2015 Jayco 27RLS
2015 Ford F250 6.7PSD
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10-21-2016, 09:30 AM
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#7
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Senior Member
Join Date: Apr 2016
Location: SW Washington
Posts: 1,024
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Quote:
Originally Posted by SouthCo
Rusty, low voltage at pedestal will cause something like this? Mike will have him try again with just the hot water heater. Didn't think about the water heaters own breaker.
Thanks for the help. Luckily we've never really had an issue with our Jayco's.
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I dont' know, I meant to punctuate that as a question rather than as a statement. Sorry if I caused any confusion.
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2009 F350 CC LB 4WD
2017 Jayco 355MBQS
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10-21-2016, 09:44 AM
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#8
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Senior Member
Join Date: Aug 2015
Location: Ottawa, ON
Posts: 1,954
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Quote:
Originally Posted by SouthCo
Rusty, low voltage at pedestal will cause something like this? Mike will have him try again with just the hot water heater. Didn't think about the water heaters own breaker.
Thanks for the help. Luckily we've never really had an issue with our Jayco's.
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No, low voltage over a resistive load will cause the current (and power) to decrease. In this case a 1500W element puts out 1500W at full power and draws about 12.5 amps. If the voltage across the given resistance drops, the current and power also drop. If the voltage were say to go down to 100V it would only draw about 10.5 amps and would only put out about 1000w of heat (Joules 1st law and Ohm's law). It is the resistance of the element that remains constant, not the power output. OTOH Inductive type loads like motors will draw more current as the voltage drops. Note that above numbers are simplified a bit using straight DC Ohm's law and does not take into account the characteristic of changing resistance with heat which relatively insignificant in Joule heating.
If the current is rising across the element, it is because the element is "burning out" and its resistance is dropping.
ETA: Oops, wrote that and then got distracted before posting, I see that DanNJanice said basically the same thing.
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2011 Jayco X19H (purchased 2015)
2008 Jayco 1007 PUP (purchased new, traded for the X19)
2018 Nissan Titan Midnight Ed.
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10-21-2016, 11:26 AM
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#9
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Senior Member
Join Date: Feb 2014
Location: MD
Posts: 3,856
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Hot water heater pulling high amps
Quote:
Originally Posted by RedHorse1
I think the PI EMS would shut the power off. "That's what it does."
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The actual pedestal breaker tripped so not sure if ems cutoff prior to that, simultaneously or not at all. My brother in law is going to plug in to the 50amp pedestal plug with a dogbone this evening and see what it does.
I really appreciate all the info and help from everybody.
__________________
2017 JayFlight 28BHBE
2014 JayFlight Swift 264BH (Sold)
2007 GMC 2500 Sierra Classic Crew Cab LBZ Duramax / 6spd Allison
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10-21-2016, 12:55 PM
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#10
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Senior Member
Join Date: May 2015
Location: Campbell Hall
Posts: 2,835
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Left field suggestion:
Run the water heater on propane. Only A/C and microwave as large loads.
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TT 2015 19RD "TheJayco"
TV 2003 F-350 "Montblanc" - Housebroken chore truck
Sitting in The Cheap Seats.
And proud of it!
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10-21-2016, 08:03 PM
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#11
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Senior Member
Join Date: Feb 2014
Location: MD
Posts: 3,856
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Hot water heater pulling high amps
They don't ever use the microwave like us. Always cook everything outside. And he did use propane for hot water last night. Today my BIL ran just the ac and it stayed around 8amps but it's cool outside. He ran just the hot water heater and it stayed around 11amps. So thinking it may be the ped after all. Told him to use the 30amp to 50amp dogbone and run both like yesterday evening but he never did. I'm keep telling him to join this forum. I appreciate all the help and knowledge you all provide. Thank you everyone. If we find out it's not the ped, I will update this.
__________________
2017 JayFlight 28BHBE
2014 JayFlight Swift 264BH (Sold)
2007 GMC 2500 Sierra Classic Crew Cab LBZ Duramax / 6spd Allison
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10-22-2016, 05:55 AM
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#12
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Junior Member
Join Date: Aug 2015
Location: Poconos
Posts: 22
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Volts divided by watts = amps. Watts are constant. If volts fluctuate so will the amps. The lower the volts, the higher the amps will be. Plug in & turn on the load (a/c, w/h) & then meter volts. Under load your volts can drop causing your amps to go high. If the wire providing power to the pedestal is not sized properly there will be voltage drop issues under load. Ex 1500 watt water heater divided by adequate 120 volt, will pull 12.5 amps but a 1500 watt heater with inadequate 105 low volts will pull 14.2 amps. Also low voltage is very hard & damaging to motors, like your a/c. Remember volts can meter good without load being applied, make sure you meter volts with the load on. Operating range 110 - 120v. On 240v systems it's 220v - 240v. It's not uncommon to see 5-6volts higher then 120v or 240v, pending the loads on the system. It should never be lower then the 110 - 220,v problems will surface.
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10-22-2016, 06:05 AM
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#13
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Junior Member
Join Date: Aug 2015
Location: Poconos
Posts: 22
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Be careful using the dog bone & plugging into a 50a. It could overload the amp rating of you fuse panel. The panel could become warm or even hot. The main breaker in the camper should protect it, but heat could still build up in the panel. Heat is not good on electrical systems.
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10-22-2016, 09:14 AM
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#14
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Senior Member
Join Date: Jun 2016
Location: Orlando
Posts: 281
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In a resistive circuit, wattage is not constant, resistance is.
I = V/R
A = W/V
120V at 1500W = 12.5A resolves to 9.6 ohms for the element
100V/9.6 ohms = 10.4A
90V/9.6 ohms = 9.4A
Edit - saw similar had already been posted - twice!
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11-21-2016, 07:00 PM
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#15
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Senior Member
Join Date: Apr 2016
Location: Fortuna Foothills
Posts: 1,862
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Before anybody does anything, what is the voltage at the pedestal??? That is where all troubleshooting (and advice) starts without this one fact everything is pure speculation and conjecture.
Vicr
IBEW Local 46
Seattle, WA
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