Truma anomaly on Comfort mode

[GraniteStaters]

We had an error on our Truma this AM after changing it from ECO mode to COMFORT mode.  The remote was flashing.  I checked the external LED and confirmed the message to be the Truma circulation pump not having sufficient water, no prime.  We are using our fresh water tank at this campground.  It didn’t take long to realize that after I had sanitized the fresh tank, which requires bypassing the Truma, that I hadn’t turned it back on.  We hadn’t used any hot water since arriving so hadn’t noticed.  We turned the valve to inline and heard the water fill the Truma, but shortly after cycling the outside and remote switches we still flashed in COMFORT mode.   I was puzzled for a bit, but the error was the same sssllsll indicating the Truma circulation pump had insufficient water aka prime.  I then bled the kitchen hot faucet and had spurts of air and then steady flow.   I recycled the outside and remote switches and we were back in business.  I believe the Truma didn’t flash in ECO mode because there was water in the unit.

[Overland]

One of the things I was told during delivery was to bleed the air out of the Truma when starting it up the first time after being drained. I think that the small reservoir in the unit won’t fill properly unless you open a faucet to let the air escape. The easiest way to do it is to use the pressure valve on the unit itself. I’ve gotten into the habit of releasing the valve for a second whenever I turn on the outside switch, just to make sure. You should probably test that valve once a year anyway, just to make sure that it’s working. 

[AndrewK]

40 minutes ago, Overland said:

One of the things I was told during delivery was to bleed the air out of the Truma when starting it up the first time after being drained. I think that the small reservoir in the unit won’t fill properly unless you open a faucet to let the air escape. The easiest way to do it is to use the pressure valve on the unit itself. I’ve gotten into the habit of releasing the valve for a second whenever I turn on the outside switch, just to make sure. You should probably test that valve once a year anyway, just to make sure that it’s working. 

Overland, pressure release valves are prone to not fully close after being released.  I would be hesitant to use it for that purpose.  I have had more that one fail in the past (Not on the Truma).

[bhncb]

1 hour ago, GraniteStaters said:

 I believe the Truma didn’t flash in ECO mode because there was water in the unit.

In ECO mode the circulation pump, and burner, won't come on unless the internal temperature is below 41degrees. In Comfort mode the threshold is 102 so what you experienced could be normal operation under the circumstances.

[Overland]

20 minutes ago, AndrewK said:

Overland, pressure release valves are prone to not fully close after being released.  I would be hesitant to use it for that purpose.  I have had more that one fail in the past (Not on the Truma).

Most water heater manufacturers recommend you test the valve annually. Some recommend every six months. I don’t know if Truma has a recommendation. I’d think that if the valve won’t close after testing then that’s a good sign that it needed to be replaced anyway. 

[Ray and Susan Huff]

I'm confused . . . . I understood that the Truma Comfort, as installed in the Oliver, is not the Truma Comfort Plus model and thus does not have the recirculating pump that keeps hot water in the lines when set to comfort mode, giving instant hot at the tap, without having to wait for the hot water to get there.  The Truma AquaGo Comfort heater is one of three models: AquaGo Basic (heats on demand); AquaGo Comfort (heats on demand and maintains hot water in the small tank at all times); AquaGo Comfort Plus (heats on demand, maintains hot water in the small tank at all times, and recirculates the hot water through the supply lines to the faucets so the water is always hot at the tap).  I believe the Comfort model still has the rocker switch for both modes, but when on Comfort, functions the same as on Eco.  

Oliver is installing the AquaGo Comfort.  Water in faucet supply lines is not kept hot at all times.   At least this is what I was told.

[Overland]

The Truma Comfort has a circulator but it circulates water within the unit itself, not through the whole trailer. 

[bhncb]

20 minutes ago, Overland said:

Most water heater manufacturers recommend you test the valve annually. Some recommend every six months. I don’t know if Truma has a recommendation. I’d think that if the valve won’t close after testing then that’s a good sign that it needed to be replaced anyway. 

So manually opening the valve only tests whether it will re-close, not if it will release automatically under high pressure.🤨

[GraniteStaters]

The valve I was referring to is the bypass/isolate valve to remove the water source.

[Overland]

42 minutes ago, bhncb said:

So manually opening the valve only tests whether it will re-close, not if it will release automatically under high pressure.🤨

What it does is make sure that the valve is moving freely, since it can get stuck with deposits or just from lack of use.

[bhncb]

9 minutes ago, Overland said:

What it does is make sure that the valve is moving freely, since it can get stuck with deposits or just from lack of use.

Just stirring the pot. I usually open mine for air whenever draining. Truma does call it a "Test Lever"