Installing a new Transfer Switch in a 2015 37 FS

[rgolding]

We have owned our Seneca 37FS since October, 2015. We have over 75k miles and over 1500 hours on the generator. Though we have a residence, we are in the Seneca about 9 months a year.

During this 4 plus years experience, I have had to replace the Transfer Switch, twice. The first time was during warranty and though inconvienient, I learned a lot. That time the Shore power wouldn't kick in and we lived on the generator for about a week. New part was sent to our location and I was talked through the exchange.

Earlier this past Summer, the generator started not wanting to come on line. I was suspecting the same problem and ordered a replacement Transfer Switch.

Lived without the generator on our drive to Florida in early November. Shore Power worked when we would get to a campground. That is, until we made the final move to the place we would spend the Winter months. Plugged in and now the shore power would not kick in. Called the great techs at Motor Homes 2 Go and they ordered the new switch for me and also told me how I could just wire around the switch until it arrived.

Fast forward to yesterday, when we had a rare cool day in Florida and it was time to replace the Transfer Switch. With the addition of 3 Male 50 amp range plugs and wire pigtails and 3 50 amp female plugs. The new transfer Switch is now in place, working great and totally removable from the system.

I now carry a spare transfer switch, just like a spare water pump, but now if the sucker acts up again, I'll just unplug it from the system and have the shore power or generator available to use with a manual plug in from one to the other.

Keep it simple - they never had trouble with the power windows on a Model T.

[JimD]

What model transfer switch is failing? Is there any other brand available that may have a better track record?

[rgolding]

The unit is a Progressive Dynamics, Inc., Model - PD52DCS. I don't really have a lot of experience with transfer switches, as far as reliability. I've talked to other owners, that have had different Manufacturers and they have had problems or know someone that has had a problem, also. Nothing really chronic, but if you play this game long enough, you will see all the cards in the deck.

One thing I've been told by technicians is to not have shore power plugged in and then start the Generator. Best to have everything neutral and then either plug in shore power or turn generator on. That is what we have done since the first time we experienced a problem back in October of 2016. However, to me, those instructions always contradicted the use of the generator starting and coming online when 110 volt power goes off.

[SloPoke]

Originally Posted by rgolding

One thing I've been told by technicians is to not have shore power plugged in and then start the Generator. Best to have everything neutral and then either plug in shore power or turn generator on.

Coming from a background in electrical engineering... and having taken my Transfer switch apart twice now... I have a personal opinion that some might argue with.

First... the contacts on a commercial 5HP motor contactor that powers a similar load are WAY MORE HEAVY DUTY than the contacts of the small relay (they are not contactor grade) relays that are part of the PD(Progressive Dynamics)transfer switch. Motor contactors are designed to open/close circuits that have a full load. The PD relay contacts are not anywhere near that.

After tearing my Transfer switch apart - (note - it is not the first one in our Seneca) and troubleshooting a problem like Rick describes - I established a strict and rigid procedure that insured that there would be NO LOAD on the contacts of the transfer switch when they were opening or closing the relay contacts of the transfer switch. Since that time... we have not had a problem, but feel that the transfer switch is not designed / capable of switching power when there is any "moderate to heavy" load that is left on in the motorhome.

That means...we turn everything off in the Seneca when we switch to / from Generator power AND everything is off when we plug the Seneca into shore power - where the transfer switch has to engage the shore relay when shore power is connected. In winter, we can have up to 6 portable electric heaters connected to the Seneca... (6 X 1500W can be 9000W of load on the transfer switch relay) that can burn the contacts on these undersized contacts. Yes - both of the transfer switch relays are open, when the shore power is connected... only then does the shore side relay engage, close those contacts and provide power to the motorhome.

Switching power is much different than contacts that are already made... I just don't think that the Transfer switch is built for switching between shore and generator power when the applicances and heaters are left in the on position. So far - this has worked.

[JimD]

I am a little confused. Why would an electrical appliance be already turned on before power is available? I mean anything with a serious draw such as an AC. You couldn't turn the microwave on before power is on. For the electrically challenged, think about when you plug in a power cord when the item is already turned on. See the cord contacts spark.

Oh wait, I just remembered. We replaced the transfer switch in my son's toy hauler because it was chattering. His big 5K genny had blown up and he tried plugging into a small inverter unit while camping at Stagecoach. The little generator kept conking out and he didn't know why. When he finally connected to his home 50 amp service one of his AC units turned on. Kids, what can you say.

As an electronic tech I totally agree that energizing a relay when a large current draw will be taking place is hard on the contacts. The transfer switch is basically a glorified relay. You would have hoped that they were designed to handle 30 or 50 amp service.

I also would have questioned why one would fire up the genny when shore power is available but I do it frequently. While dry camping I often have my little inverter generator feeding the shore power line and when the need arises to use the AC or microwave, I will fire up the 4K unit without shutting down the little one. I then fire up the high power appliance for the period required, turn it off, let the 4K cool some and then shut it off. The little unit then is back online without my help. The only constant load while transferring is the converter.

[SloPoke]

Originally Posted by JimD

I am a little confused. Why would an electrical appliance be already turned on before power is available?

So think of it this way.. fireplace heater 1500W, Four electric space heaters @ 1500W. Leave your heat pump set to heat??? add it all up - over 7,500W and not including converter and anything else that is connected. It is 20F outside and you go to the grocery store to get some supplies.... and while you are gone - the power goes out twice while you are gone.

7500W / 120v = 62A of load. divide that in half across both lines and you have 31A of load on that teeny-tiny-contact of the transfer switch. It is going to arc and carbon those contacts with each and every open/close of that relay.

Eventually, that inexpensive, marginally sized relay is going to carbon the contacts and fail.

Who remembers carrying a point file with them in their 60's era car? the points in the Distributors had the same issue... carboned up and failed.

[Florida Ranger]

This is the best advice that anybody has put on the forum in a long time. I all ready do this when hooking up power to coach... Thanks very much..

[javamon]

Originally Posted by SloPoke

...Who remembers carrying a point file with them in their 60's era car? the points in the Distributors had the same issue... carboned up and failed.

Thanks to all for the good info.

[javamon]

Originally Posted by rgolding

Fast forward to yesterday, when we had a rare cool day in Florida and it was time to replace the Transfer Switch. With the addition of 3 Male 50 amp range plugs and wire pigtails and 3 50 amp female plugs. The new transfer Switch is now in place, working great and totally removable from the system.

I now carry a spare transfer switch, just like a spare water pump, but now if the sucker acts up again, I'll just unplug it from the system and have the shore power or generator available to use with a manual plug in from one to the other.

Keep it simple - they never had trouble with the power windows on a Model T.

Would be great if you or anyone who is familiar with this could detail how you wire your transfer switch to be able to take it out of the loop. Would be very valuable info to many. Thanks!

[hammer55]

good explanation there, glad someone took the time to write it out

Originally Posted by SloPoke

So think of it this way.. fireplace heater 1500W, Four electric space heaters @ 1500W. Leave your heat pump set to heat??? add it all up - over 7,500W and not including converter and anything else that is connected. It is 20F outside and you go to the grocery store to get some supplies.... and while you are gone - the power goes out twice while you are gone.

7500W / 120v = 62A of load. divide that in half across both lines and you have 31A of load on that teeny-tiny-contact of the transfer switch. It is going to arc and carbon those contacts with each and every open/close of that relay.

Eventually, that inexpensive, marginally sized relay is going to carbon the contacts and fail.

Who remembers carrying a point file with them in their 60's era car? the points in the Distributors had the same issue... carboned up and failed.

[RetiredOne]

Originally Posted by SloPoke

In winter, we can have up to 6 portable electric heaters connected to the Seneca... (6 X 1500W can be 9000W of load on the transfer switch relay)

A bit of a thread drift... but does anyone else see an issue here? That a $150K rig requires 6 portable heaters to provide heat? The engineers that design these expensive rigs can't design an onboard system to heat it, without having to use multiple external devices not part of the original rig....

[RVermont]

I think the designers engineer these for the majority of people who use their units during the may-September seasons. They will tell you they are not designed for four season usage. The on board heater works great for most situations , all be it loudly. but if you are on a site with electricity included vs paying for propane most of us will install heaters and use the electric that we are paying for in our camping fees.

I think the real question should be why they don't make a cold weather option available for those of us that would like to use it year round.

[CatheyMartin]

We believe that our transfer switch has gone bad (power to the microwave with the generator on but none with shore power). Can you tell me where it is located in the 2015 37FS? And can you tell by looking at it if it has gone bad [burned contacts, etc) or do we just replace it and see if the new one works? Thanks for any help.

[Grumpy]

Originally Posted by CatheyMartin

We believe that our transfer switch has gone bad (power to the microwave with the generator on but none with shore power). Can you tell me where it is located in the 2015 37FS? And can you tell by looking at it if it has gone bad [burned contacts, etc) or do we just replace it and see if the new one works? Thanks for any help.

Do you have power to everything else when on shore power, TV a/c etc?

[CatheyMartin]

No, the refrigerator and various other plugs don't work on shore power but do on generator.

[Grumpy]

That does sound like the transfer switch. Not sure where it is located, but you should here it click shortly after starting geny, so that would help lead you to it. You can also check the connections simply by removing the cover. Make sure the geny isn't running or plugged in.

[CatheyMartin]

Rgolding,
Can you tell me where you found the transfer switch? I know it is under the bed but is it in same area as the breakers and converter or in the area at the head of the bed?
Thanks for your help.

[Grumpy]

Originally Posted by CatheyMartin

Rgolding,
Can you tell me where you found the transfer switch? I know it is under the bed but is it in same area as the breakers and converter or in the area at the head of the bed?
Thanks for your help.

His post is from 2019. Hopefully someone else will jump in.

[pconroy]

I don't have that model but I bet the picture of the ATS in mine will be very close to yours. Its the black, square box at the top with the white label. Big gray conduit going in on the left. Orange/white wires going in on bottom.

[pconroy]

Originally Posted by CatheyMartin

And can you tell by looking at it if it has gone bad [burned contacts, etc)

Oh yeah...........


I replaced that white plastic bus bar with another one that I happened to have. [ They're available on Amazon. ] Had I not had one, I would have used Wago style connectors. I've read that PD has gone to Wago connectors in newer installs.

Oh yeah, I now have a dedicated smoke alarm inside this area.