RV News RVBusiness 2021 Top 10 RVs of the Year, plus 56 additional debuts and must-see units → ×

Thread Tools Search this Thread Display Modes
Old 06-07-2017, 04:56 PM   #1
3 Rivet Member
Colfax , California
Join Date: Mar 2016
Posts: 204
Max incoming psi for Truma Combi water heater

I'm wondering how many folks have read up on the Truma Combi disclaimer regarding incoming city water pressure.

Despite the reality of domestic water supplies in the US frequently exceeding 50-60 psi and that most aftermarket RV pressure regulators reduce to the RV industry "standard" of 50 psi, the Truma manual is very specific in stating that the maximum expected incoming psi should be no more than 40.6 psi. In fact, Truma states that they will not cover damage traceable to water pressure exceeding 40.6 psi.

Anyone tested their home or RV park pressure lately?
Bborzell is offline   Reply With Quote
Old 06-08-2017, 08:08 PM   #2
1 Rivet Member
2017 Basecamp
SoCal , California
Join Date: Mar 2017
Posts: 18
I noticed that in the manual for the Truma as well. The Basecamp has a pressure regulator that does not reduce it to that level, the regulator reduces the city water to around 50 psi, according to the manual. Unless there is another undocumented regulator to the Truma, it would seem it is too high.

More info here:
Joe_Julie is offline   Reply With Quote
Old 06-09-2017, 12:24 AM   #3
3 Rivet Member
Colfax , California
Join Date: Mar 2016
Posts: 204
I received a return call from Truma today; unfortunately, it went to voice mail.

Gist of the message was that there is a regulator going into the Truma. It wasn't clear whether she was referring to the AS installed regulator which I understand goes to 50 psi or another Truma installed regulator. In any case, if there is a regulator that goes to <40.6 psi, it is thus far undocumented.

I will call her back tomorrow and finish this up by reporting on the discussion.
Bborzell is offline   Reply With Quote
Old 06-09-2017, 11:16 AM   #4
3 Rivet Member
Colfax , California
Join Date: Mar 2016
Posts: 204
Nothing is simple

I called Truma back today. They indicated that there is a pressure regulator in the cold water line that is part of the Truma package. They said that it regulated between 40 and 50 psi.

I pointed out that the Truma manual disclaims warranty coverage for unit failure caused by incoming water pressure that exceeds the 40.6 psi limit. Their response was that, since the regulator was supplied with the Truma unit, that the warranty would honor damage due to excessive water pressure.

There are a couple of issues associated with this response that are a bit troubling. First, the warranty is time specific and failure due to excessive water pressure, even if caused by the regulator delivering water to the appliance at 50 psi after the term if the warranty, will be the responsibility of the owner. The other issue is the reality that pressure regulators fail to deliver at the rated specification at a high rate out of the box and, even if they start out on spec., they often lose that performance over time.

Though I am aware that this unit has been used sucessfully in Europe for some years, my experience traveling in Europe suggests to me that high water pressure in domestic water delivery systems is not a rampant problem.

If the 40.6 psi limit is real, then the protection offered by the Truma supplied regulator is suspect, in my mind, because of the potential 10 psi excess allowed by the Truma supplied regulator. It is certainly possible that the Combi could function as expected during the term of the warranty, but fail due to excess pressure allowed by the regulator limit variability post warranty. Then again, regulators lose their rated specification over time with some consistency.

None of this would be troubling for the vast majority of RV water systems that are designed in the US to operate at 50-60 psi, but the Combi has an upper psi limit that was apparently significant enough to point out in the Truma manual with a warranty disclaimer.

Providing a regulator that exceeds that 40.6 psi limit is a bit troubling, in my view. It might be a slowly ticking time bomb that only goes off after the warranty expires.
Bborzell is offline   Reply With Quote

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Incoming 2014 16' Sport renderit 2005 and newer - Bambi all models 61 03-05-2014 06:20 PM
Max PSI ElCamino Man Tires 38 09-10-2012 09:30 AM
100 PSI or 70 PSI? '92 300LE fangthorpe Airstream Motorhome Forums 5 09-16-2010 11:11 AM
incoming power galscotty Electrical - Systems, Generators, Batteries & Solar 7 09-01-2008 04:45 PM
Manual says ST225/75R15LRC 50 psi -- PO used ST225/75R15LRD at 65 psi Driver1 Tires 3 06-23-2008 09:26 PM

Featured Campgrounds

Reviews provided by


This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.

All times are GMT -6. The time now is 09:29 PM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.