My 2002 Monaco Windsor is parked at home in 0 degree weather. I turned the heat pump on 40 degrees to keep it thawed. I just went out to check and I found no power. I've got 50 amps going to the m/h and it's working. I opened my panel and the breakers are on (yes, I checked by throwing them off then back on). I've got a Xantrex RS2000 Sine Wave Inverter/Charger and when looking at the control panel it showed a FAULT --- "Contacts Welded". What does that mean and how do I fix it? Does that have anything to do with the heat pumps?I know a heat pump doesn't work very well below a certain temperature but I wouldn't think it would cause them to not have any power at all.I do have power at the thermostat and am able to cycle through the settings. OH, I nearly forgot, the batteries are at 13.2 volts and some outlets running from the inverter are powered with 120 volts so it's not a low battery issue.Thanks for any help.

Sounds like transfer switch / relay contacts are stuck/welded together, this could be the TS inside the Xantrex,That switches between shore power or inverter powerCould it be there was a power outage recently during the night, or a fluctuation brown out, heat pump is basically A/C in reverse, bringing in heat and blowing cold air outside, I don't know how your coach is wired, but switching power feeding running compressors is not good for the switch contacts, it could have happened automatically if shore power was interrupted, main TS for the RV, would have dropped out , and the Xantrex switch to inverter mode, then switch back to charge mode when shore power returned, fluctuations would cause more problems than than complete shore power outage, fluctuations would cause low and high voltage swings and current surges which could arc and pit contacts, you need to find and replaced the welded contacts, before more damage is done to the RV electrical system, contact a mobile RV tech to come look at your RV wiring

At Zero degrees heat pumps should shut down (in fact long about freezing they should shut down) I doubt the heat pumps run through a 2000 watt inverter as they would shut it down due to overload.Contact Xantrex to find if the inverter is still under warranty and cost of repair. There is also a Xantrex repair guy in Quartzite AZ but I have lost his contact info.

Do you have power at the 120v outlets in the RV? - If not, that would support the idea it's in the transfer switch. - If yes, it's likely not the transfer switch.

The manual shows an external TS for shore/gen, then the charger/inverter then the CB panel. This suggests that any charger/inverter internal TS contact problem could effect all AC power including the heat pumps.A number of different problems with the heat pumps or elsewhere could cause a contact issue. A power outage problem cause contact arcing as the power goes off and on. Including the inverter switching on/off to supply AC power to the panel. While my chager/inverter is not a whole house type unit I never leave the inverter on which allows automatic AC switching. I also turn off all loads before connecting/disconnecting AC shore power. Both of these significantly reduce relay contact arcing.

Heat pumps don't work at 0F and I would not leave them on at 0F. In fact I have 2 dedicated 20A circuits for ceramic heaters. The water area includes both a DC heater and AquaHot register. This leaves the fresh water tank which is only protected by the AquaHot. Therefore in really cold weather I'd use the electric heaters and Aquahot or winterize.

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dougrainer
Nomad
Feb 17, 2021
Bay Heater Instructions. This heater may have a Temp switch located ON the Heater, instead of the hidden behind the water Bay panel auto Tstat. Doug

The heater is controlled using two switches, one on the heater itself and a
remote “SYSTEMS HEAT’ switch located in an inside overhead compartment
next to entrance door. Both switches must be in ON position for the heater to
operate. Either switch in the OFF position will turn the heater off.
rgatijnet1
Explorer III
Feb 17, 2021
Welded contacts is sometimes the result of rapid cycling of the electrical contactor. The 15 power outages certainly could have contributed to this situation. Contact damage can also occur with voltage that has gotten too low to properly hold the two contacts tight.
dougrainer
Nomad
Feb 17, 2021
Tinstar wrote:
dougrainer wrote:
PastorCharlie wrote:
Why would a 2,000 watt inverter be wired into a heat pump circuit?

Its not. He just has 2 problems. Doug

Doug, That's what I was wondering. I couldn't imagine them being fed from the inverter but I didn't know. Does the a/c/heat-pump wire straight into the 120-volt circuit panel and it is not controlled by the inverter. I don't have aqua-hot. I have ran extension cords and am using small space heaters to keep water from freezing.

Sunday morning, I had about 15 power outages that were only out for about 3 to 5 seconds which may have caused the problems. Have you ever seen "welded contacts" as a fault?

NO Aqua Hot? VERY unusual. I cannot remember when any of the hi line Monacos from 20 years ago did NOT have the optional Aqua hot. So same scenario, when the Ambient temp drops below 36/38 degrees the furnaces will automatically start and run, as long as the LP is turned ON. Your model should also have the 12 volt water bay heater that is turned on by a tstat switch mounted in the water bay inner wall, when the temp in the bay goes below 34 degrees. BUT, you MUST have that Heater switch turned ON. the switch is on the inside by the monitor panel display board. Now, to your question. NO OEM will ever run a roof AC or HP thru the Inverter/charger. Monaco did not. So, any loss of 120 power to the roof HP's is not caused by the Inverter/Charger. You DO have a Intellitec Energy Management System(EMS) that the roof HP's 120 power does go thru. THIS system can kill 120 power to the roof HP's if it is malfunctioning, but the Inverter will not cause such a problem. Your EMS wall display will show the status of the Power to the roof HP's. Doug
Tinstar
Explorer
Feb 17, 2021
dougrainer wrote:
PastorCharlie wrote:
Why would a 2,000 watt inverter be wired into a heat pump circuit?

Its not. He just has 2 problems. Doug

Doug, That's what I was wondering. I couldn't imagine them being fed from the inverter but I didn't know. Does the a/c/heat-pump wire straight into the 120-volt circuit panel and it is not controlled by the inverter. I don't have aqua-hot. I have ran extension cords and am using small space heaters to keep water from freezing.

Sunday morning, I had about 15 power outages that were only out for about 3 to 5 seconds which may have caused the problems. Have you ever seen "welded contacts" as a fault?
pianotuna
Nomad III
Feb 17, 2021
At 25 f (-3.88c) heat pumps become less efficient than resistance heating.

They work well down to 40 f (10 c)
naturist
Nomad
Feb 17, 2021
CA Traveler wrote:
Heat pumps don't work at 0F and I would not leave them on at 0F. In fact I have 2 dedicated 20A circuits for ceramic heaters. The water area includes both a DC heater and AquaHot register. This leaves the fresh water tank which is only protected by the AquaHot.

Therefore in really cold weather I'd use the electric heaters and Aquahot or winterize.

X2. Heat pumps are more or less useless below freezing, and actually lose function starting around 40 degrees F.
dougrainer
Nomad
Feb 16, 2021
You did not state IF you have the Aqua Hot system activated and ON. Heat Pumps are completely separate from the furnace/water heater system(Aqua Hot). IF you did not have the Aqua Hot activated and you are NOT inside storage, you may have a burst Aqua Hot reservoir if the Propylene is not at the correct antifreeze concentration. On your HP system, IF the Aqua Hot was activated, then the Aqua Hot furnace system would have come on once the ambient temp dropped below 36/38 degrees. Doug
dougrainer
Nomad
Feb 16, 2021
PastorCharlie wrote:
Why would a 2,000 watt inverter be wired into a heat pump circuit?

Its not. He just has 2 problems. Doug
PastorCharlie
Explorer
Feb 16, 2021
Why would a 2,000 watt inverter be wired into a heat pump circuit?
down_home
Explorer II
Feb 16, 2021
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