Solenoid that operates the HWH slideout is getting warm/hot. Is this normal?

[Jim]

I'm supposed to pull out of here tomorrow and I like to do a short test run prior to leaving. So after my test run up the road, I noticed one of the solenoid's that operates my HWH pump is still getting hot. It's not so hot that I can't touch it, but it's pretty warm none-the-less. The other is cold. I don't know if this is normal or not. I never noticed it before, and if I hadn't recently been trouble shooting my slideout problem the other day, I would not have thought to check it today.

Does anyone know if this is normal or not? I called HWH but they're backed up so I don't expect a call back from them until tomorrow.

 

[Kevin D Pem]

Solenoid valve, or relay!?

 

[Jim]

Solenoid valve, or relay!?

Solenoid

 

[RKins]

Are you having trouble closing the FWS? How long does it take to close the FWS? I think if the solenoid is left active more than a minute or two they will "warm to the touch" and if left active a long time they can burn up the windings. Example is if you have a lazy jack that takes a long time to retract.

 

[Jim]

Are you having trouble closing the FWS? How long does it take to close the FWS? I think if the solenoid is left active more than a minute or two they will "warm to the touch" and if left active a long time they can burn up the windings. Example is if you have a lazy jack that takes a long time to retract.

No, the slides are working fine. The concern, and it may be a normal condition, is that one of the two solenoids is getting between warm/hot to the touch, even when I'm not in the process of opening/closing any of the slides.

For instance, the ACC switch must be in the 'on' position for the generator tray to extend or close. But just leaving the key turned to the ACC position will cause the solenoid to get warm/hot over a period of 15-30 minutes. So taking that a bit further, I drove the coach for 30 minutes and the solenoid was warm/hot to the touch. But only one of them, the other remained ambient temp.

It doesn't seem to get so hot that you can't put your hand on it, but my fear is that over an extended period of driving, the temp will continue to increase and the solenoid will burn up, or worse, start a fire.

 

[GTS225]

As an electrical maintenance tech, (retired), I saw this phenomenon quite often. You see, a solenoid, and/or relay, is actually a coil of small gauge wire wrapped around a steel or iron core. The act of energizing that relay/solenoid causes current to flow through the wire, with the heat that naturally is involved, and the longer it's activated, the warmer it gets. Now, there IS a limit, but I suspect you haven't gotten near that yet. If you can't touch it, then it's too hot.
There's also the possibility (slim) that this particular solenoid isn't rated for "continuous" use, and could burn out the coil if it's left on too long. My suggestion is that you find a spare to carry with you, which isn't such a bad idea for many of the electrical relays in such a complex rolling earthquake.

Roger

 

[Jim]

As an electrical maintenance tech, (retired), I saw this phenomenon quite often. You see, a solenoid, and/or relay, is actually a coil of small gauge wire wrapped around a steel or iron core. The act of energizing that relay/solenoid causes current to flow through the wire, with the heat that naturally is involved, and the longer it's activated, the warmer it gets. Now, there IS a limit, but I suspect you haven't gotten near that yet. If you can't touch it, then it's too hot.
There's also the possibility (slim) that this particular solenoid isn't rated for "continuous" use, and could burn out the coil if it's left on too long. My suggestion is that you find a spare to carry with you, which isn't such a bad idea for many of the electrical relays in such a complex rolling earthquake.

Roger

Thanks Roger. I replaced both of the solenoids so I have the old as spares. And yes, before I repaired the damaged ground, the solenoid was getting so hot that it was uncomfortable to tough it. Since the repaired ground, it's nowhere near that now. Again, thank you!

 

[Kevin D Pem]

My guess is it is 100% duty cycle. It is common coils ca obtain, and run at 60 degrees above ambient.

That said, I would look for a faulty limit switch. Is the pump running? A faulty switch may be causing the pump to continuously run as well.

 

[Rd1]

For instance, the ACC switch must be in the 'on' position for the generator tray to extend or close. But just leaving the key turned to the ACC position will cause the solenoid to get warm/hot over a period of 15-30 minutes. So taking that a bit further, I drove the coach for 30 minutes and the solenoid was warm/hot to the touch. But only one of them, the other remained ambient temp.

Where newmar installs the HWH pump, is not very suitable. The pump, wires, etc are all exposed to dirt, moisure, etc.. I always wondered if there was a practical way to 'box' it up.

While driving or ACC ON, If you are not running the FWS, or the lev.jacks, or the entry steps, or the gen.bay, the hwh pump is dormant. There should be no heat in the solenoid, unless it had an issue.

OTH, you may want to inspect the fues for the HWH pump, just to make sure that was not the cause. Those have a nasty habbit of burning up due to exposure to moisture (see pic). Also may want to inspect the ground wire. This is a common failure in 'older' units.

It is a 40a fuse.

 

[Jim]

Where newmar installs the HWH pump, is not very suitable. The pump, wires, etc are all exposed to dirt, moisure, etc.. I always wondered if there was a practical way to 'box' it up.

While driving or ACC ON, If you are not running the FWS, or the lev.jacks, or the entry steps, or the gen.bay, the hwh pump is dormant. There should be no heat in the solenoid, unless it had an issue.

OTH, you may want to inspect the fues for the HWH pump, just to make sure that was not the cause. Those have a nasty habbit of burning up due to exposure to moisture (see pic). Also may want to inspect the ground wire. This is a common failure in 'older' units.

It is a 40a fuse.

Yep, all fuses are fine and I removed the grounds, wire brushed them and re-connected them. Solenoid still gets "warm". That being said, I just finished a 5-hour leg, checked the solenoid and found it to be cool to the touch. So heck, who knows what's up? I'm going to ignore it for a while and see what happens.

 

[RKins]

Do you make sure the HWH system is "Off" when not in use, like when driving or when you have the key in ACC but not using the HWH? Leaving the control panel on may keep the one solenoid on, but I would think it shouldn't. Which HWH system do you have? 725?

 

[RKins]

Solenoid

I was also kind of wondering if you are actually talking about the hydraulic solenoids that screw into a distribution header of the system and not the relays that controls power to the HWH system. There are two HD relays that control power to the system. The hydraulic solenoids are round and maybe 6-7 inches long. The relays are square and mine are attached to the round pump motor.
These are solenoids - left 1/4 of pic - mine still have the "T-handles" on them - newer ones I understand might not. But they are cylindrical.

These are the control relays, strapped to the round pump motor.

 

[Jim]

Pictures 2 & 3 are the solenoids that I'm talking about. If I understand your post, you're saying that these are not solenoids, they are control relays?

 

[BGMAC]

Jim, a solenoid is a device that mechanically moves something and relay basically a device that uses a lower current to control higher current.
Anyway, there are contacts inside for the high current side that may be corroded or burnt from use reducing the contact surface causing resistance thus heat. I’d replace them.

 

[Jim]

Jim, a solenoid is a device that mechanically moves something and relay basically a device that uses a lower current to control higher current.
Anyway, there are contacts inside for the high current side that may be corroded or burnt from use reducing the contact surface causing resistance thus heat. I’d replace them.

Thanks for the explanation, @BGMAC . After a brief conversation with HWH yesterday, this seems to be acceptable. I have pretty much put this on the "I'm not going to worry about it" list.

 

[Kevin D Pem]

Thanks for the explanation, @BGMAC . After a brief conversation with HWH yesterday, this seems to be acceptable. I have pretty much put this on the "I'm not going to worry about it" list.

Yes relays! They are made in different duty cycles. It is all about the coil. If you need to ever replace one just spec out 100%duty cycle for the least heat.

 

[RKins]

@Jim Yes, those are relays. My concern is why are they warm/hot when the system should be off. They should only get hot when current is flowing through them.
Do you have a pic of the HWH control panel you have?