Finally upgraded to a Truma Comfort Plus model

Rustynuts

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Our 2018.5 Seneca came with a Truma water heater which I had upgraded to the comfort model and it has been great. They also have a Comfort Plus model that has an automatic circulation system to keep the water in the lines at 108 degrees but is only available as in OEM installation. Truma is very protective of their parts and will not sell this one part unless it’s needed to repair an existing unit and having the appropriate serial number but after years of trying to get my hands on the one single part needed to convert mine to a Comfort Plus, I was able to get a freeze damaged unit off Facebook Marketplace cheap. I had installed a manully triggered circulation system to save water so I just extended the return line back to the water heater compartment, installed the part in the Truma for the return line and I now have a true instant hot water heater with 108 degree water at every faucet when opened. There will be some increase in propane use but I timed it and the Truma fires for 2-3 seconds every 30 minutes to maintain the temperature so probably wont notice the difference. The Truma Comfort Plus is probably the ultimate RV water heater system IMO. Here are some pics, wasn’t a hard upgrade other than acquiring the single part. Green arrow pointing to the old Truma Comfort part and the Red arrow pointing to the new Truma Comfort Plus part which adds a connection for a return line for the recirculation pump.
 

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Sounds like you will be very happy with the new setup. What about winterization on the new system?
 
I never winterize pretty mild all year on the Oregon coast, it’s 60 and sunny today and it’s always inside. On the Truma it’s just like before just close the bypass that I installed because Jayco ignored the Truma Instructions and then just open the main drain on the Truma, they are so simple. All 3 lines, the supply, hot and the circulation line all have low point drains.
 
I took the Truma tech certification class and the instructor explained winterizing the unit this way.

"Open the yellow filter release and remove filter. Any Questions?"

Probably the best designed and functioning rv water heater available.
 
Did you have to run another line back from your furthest faucet? Trying to understand what else needs to be done to complete the system. It also looks like you can order a new unit with the serial number off an old unit. https://hydronicheatingwarehouse.co...vwyohJs7_pILmYwREkNdG3oORiB8X78EvoEH3PHG8VeDr

Yes, the kitchen faucet was the furthest away and I had already plumbed a manually triggered timed relay recirculating system from the kitchen back to the fresh water tank that worked good, but you had to trigger it with an air switch at the kitchen faucet and then wait 30 seconds while hot water from the water heater circulated up to the kitchen faucet and back to the fresh tank. Doing the Truma upgrade, I just removed the line dumping into the fresh tank (through a vent line) and ran pex from there back to the water heater. They also recommend where it connects to the back of the water heater to have and shutoff/bypass valve and a low point drain for winterizing. I have tried it out a few times and within 1-2 minutes of turning on the Truma to the Comfort setting, the water at the kitchen is 108 degrees. I came back a couple times after waiting an hour between and each time had 108 degree water instantly……happy wife, happy life :p:p

Sending you a private message

Here is a post on the original water circulation system that I put in and removed when I upgraded the Truma.

https://www.jaycoowners.com/forums/f64/seneca-modifications-39395-6.html#post816185

Here are a couple pics that show the return line plumbed into the WH compartment and the 3 connections on the back of the water heater and the basic plumbing layout from Truma.
 

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Sorry, this is going to sound dumb but I just want to make sure I'm clear as far as the unit itself goes the only difference between the comfort and the comfort plus is that pipe, theres no electrical stuff that has to be changed out? So if I were to create my own pipe assembly to replicate what you show in the pic then I could convert to the plus model (aside from adding the appropriate water lines in the rv)?
 
If you already upgraded from the Basic to the Comfort model, then yes, this one part is all you need. Before I got my hands on the part, I didn’t know if there was anything special about and there is one important thing, it has a restrictor disc in the top of the tee, it’s a copper disc with a .03125” hole in it to direct the water flow from the recirculation line and I am guessing the hole is so no air can get trapped in the lines. The copper lines are standard 3/8” tubing. The pic showing the docs down in there is looking from the bottom, it looks kinda funny as I have a led light shining in the end of the inlet to light it up.
 

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Ha, thanks, that makes it a bit harder, I feel less confident brazing a disc in as well but I'll think about it.
 
Ha, thanks, that makes it a bit harder, I feel less confident brazing a disc in as well but I'll think about it.
If you look at the pic, it looks like the tee is slightly crimped around the upper section where the disc goes. You would just fit the disc in the tee and insert the pipe and solder.
 
Ah good observation, so the disc may be sort of just floating there squished between tee and the upper section. I guess that makes sense, especially since it already has a hole in it.
 
Ah good observation, so the disc may be sort of just floating there squished between tee and the upper section. I guess that makes sense, especially since it already has a hole in it.
With a good solder job, that disc would also be soldered in place. The hard part would be the brass fitting with the 1/2NPT that attaches into the back panel with screws. I’m sure with a few copper fittings and come copper or brass flat stock, you could make something up. If you could by chance get ahold of another of the Comfort pieces, you could take two and make one of the Comfort Plus pieces with them. The back housing of the water heater would be your jig to hold everything in place while it is soldered as the knockout is already there.
 

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Disc is there to limit flow. Its a circuit setter. You could accomplish the same thing with a valve like this;

If you have room in the header.
Not the same thing. According to a post I read when somebody asked Truma about it, the disc with the small hole is to divert the flow of the hot water out though the hot water line and back through the recirculation line to the pump. The hole in the disc is to prevent an air pocket and help purge air in the recirculation system. The Truma Comfort recirculates the water in the unit itself, converting to a Comfort Plus adds the complete recirculation line in the whole hot water line run. This small hole is to help air purge out of the system when first started or after it’s been drained for winterization. When I first started mine after the conversion, I was getting an error of the pump timing out and it was because of the air in the line. I was able to get most of it out by cracking the low point drain on the recirculation line and the system took care of the rest. This drawing shows the water flow in the Comfort and Comfort Plus versions.
 

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It is a typical recirculation line. We normally install a valve before the re-circ enters the heater with a hose bib upstream of that in order to bleed the air. Close the valve and open the hose bib; all the air is pushed out of the line. Recirc pumps have no draw/suction, they are paddle wheel pumps. So if an air pocket hits the pump it stops moving water. You do not need full flow in order to keep the water hot in the piping, just a trickle. So, the disk/flow control is there to allow just enough water into the heater to allow it to fire (.4 GPM according to the website) if the water cools off. There is also a sensor to shut the pump down once the loop reaches temp.
The way this system is set up, position of the check valve, you could place two valves in line under your Kitchen sink with a hose bib between them. Isolate either of the valve and open the bib to remove the trapped air in that section of line.
20250204_153646.jpg
 
Yep, like the instructions show.
 

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I have a 2022 37M that I had Truma put in the Comfort system a few months after taking delivery because I hated the stock system so much. I have also acquired the needed copper piece to make it a plus and have had it laying around for close to 3 years not knowing how to make it work. After reading through this thread (please correct me if I am wrong) is all I need to do is run a pex line from my kitchen sink back to the brass recirculation attachment point and all will be good. Is there something I am missing or something else that needs to be done? TIA
 
Yep that’s it, install the new part in the Truma, the control board and all sensors are the same. I had originally made a recirculation system that dumped into the fresh tank, so all I had to do is redirect that line back to the water heater. On the plumbing to the sink, I just removed the 90 on the hot line up to the faucet with a tee and ran that line back to the water heater. Do note in this pic, this is from the previous recirculation setup and I had installed a check valve in the return line, you DO NOT want a check valve in the line when running to the Truma. I also insulated all the hot water lines in the return line just to help keep it warmer longer. Have used the coach twice now and the Truma Comfort Plus is amazing now and my wife is very happy, and we all know how important that is :giggle: I also installed a Thermostatic shower valve and it’s a lot nicer only having one know to adjust once you get the temp set.
 

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Thank you, now i just have to figure out where the lines are run so I can just run the return line along side them.
 

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