R25/OB Webasto heater's temp sensor location?

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baz

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Subject: R25/OB Webasto heater's temp sensor location?

Anyone know where the temperature sensor for the Webasto diesel forced air heater is located on the R25/OB NW Edition (mine will be a 2023 model)?

Its control display is in the port side cave's aft wall and wonder if the temp sensor is Part of the control box or if there's a wire running from this control box to some other location in the boat.

Was at the Seattle Boat Show on Feb 4, 2022 and was climbing all over the R25/OB they had on jacks and on display. Took as many photos as I could. I noted the forced air outlets are at various locations...

1) Large always-open rectangular vent to port side of the Nav seat. (I'm a bit concerned small items could fall through this vent)
2) Round flap open/close vent on port side below fwd stateroom's TV directing air in the berth area
3) Two round flap open/close vents on upper helm's starboard side - presumably for defogging the front and side windows, and for providing some heat output.

I attended the Seattle Boat Show yesterday Feb 4, 2022, and visited the Webasto booth. They had two models for the Webasto heater. I believe the small one (the smallest one made by Webasto) is used for the R25/OB and its model number is AT2000STC. It's spec sheet mentions SC1600B Room Thermostat with integral On/Off Switch and indicator Light.

As an aside, these Webasto heaters push their exhaust gases to the outside of the boat, and from my experience using this heater on past RT NW Edition boats find the exhaust noise is quite significant and comes close to being characterized as sound like a small wind tunnel running at speed. I chatted about this noise with the fella at the Webasto booth and he indicated there are mufflers made by Webasto that can lessen this noise level! BY THE WAY ... this Webasto Air Top AT2000STC 7,000 Btu heater's complete kit was listed at $3,521.61.
 
I assume when you say temperature sensor you are referring for the thermostat? If so It is part of the control. As far as the noise for the intake, I ran mine out under the gunnel into the cockpit. Never had an issue with the noise inside the cabin. I figured if it was cold I wouldn't be sitting in the cockpit.
 
We can hear the diesel heater running outside the boat. When we're inside the boat all we hear is the sound of the fan blowing the heat inside the cabin. But outside the boat, it's clearly audible. But it's not loud/obnoxious.

I've walked down to the dock in the evening to check on my boat and found my dock neighbor's diesel heater running 5 boats away, down the dock. I could hear it. Of course, on a deserted dock at 8pm at night, it's pretty quiet. So the sound of the diesel heater running stands out as unusual. (I did contact the owner and let them know their diesel heater was running before it emptied their fuel tank).

If you want to hear the sound of the heater running, the last few video's we published had the diesel heater running.

In this video at the 3:13time stamp, LaZina's in the cockpit talking to the camera and you can hear the furnace running.
https://youtu.be/CimEi4RpPtM?t=193

At the 10:50 timestamp here, the furnace is running the entire time we are docking.
https://youtu.be/LQ2pw5Q-hBw?t=650

The mic's on the camera also make a difference in what they pick up, as well as their position in the boat. From the bow camera, the heater is a lot less noticeable compared to the camera LaZina used to film from the cockpit.

In the R27-OB, the heater thermostat is in the cave, about even with my shin's, and of course, there's little air movement throughout the boat. As such, if I set the temp to 72, it won't shut off until the cabin's about 1,000 degrees. I usually set our thermostat around 60-63 degrees, rarely ever higher, to get the cabin comfortably warm. We've recently started leaving a small portable USB powered fan on the port side, blowing at low speed all night across the bow windows. Helps circulate air, keeps the condensation down.
 
knotflying":1ow74jt4 said:
I assume when you say temperature sensor you are referring for the thermostat? If so It is part of the control. As far as the noise for the intake, I ran mine out under the gunnel into the cockpit. Never had an issue with the noise inside the cabin. I figured if it was cold I wouldn't be sitting in the cockpit.
Click to expand...
knotflying":1ow74jt4 said:
I assume when you say temperature sensor you are referring for the thermostat? If so It is part of the control. As far as the noise for the intake, I ran mine out under the gunnel into the cockpit. Never had an issue with the noise inside the cabin. I figured if it was cold I wouldn't be sitting in the cockpit.
Click to expand...

Thanks Mike and Martin for responding.

Mike: I was referring to the exhaust noise on port side, and not the air intake. As Martin/Submarine has mentioned, and which I agree with, the exhaust noise can be significant and easily heard as you approach the boat with the heater running. It's not too annoying, but noticeable.

So the temp sensor/thermostat is inside the round/squarish control box. This what I suspect as I've had same Webasto heater on my previous R27/OB, and yes, it needs to be set at a lowish setting otherwise the rest of the boat's interior will get super hot. I was just wondering if the Webasto things/setup have changed since 2018.

This heater also needs to be run for short periods every 30 days for maintenance reasons. I did this on the R27/OB and the Webasto never ever gave me any issues.

The only issue I have with the overall setup is the diesel tanks filler location on port side gunnel... its awkward to access when starboard side docked. Also there's no knowing how full/empty the diesel fuel tank is. On the R27/OB I found the fuel tank was visible from the inside cabin and viewing it from the underside of the stove unit. I used an IR temp sensor gun and pointed it at the tanks side and slowly moved it up and down to see when the temp changed to give me some idea how much fuel was in the tank. The fill nozzle intake tube down to the tank is curved so its not possible to use a normal/traditional dip-stick method. So I ended up just keeping it topped up now and then.

Warning to others: Avoid placing a fender over the Webasto heater's exhaust port. The exhaust heat will surely melt the fender.
 
Submariner":23wzcit1 said:
The 2021 and newer r27-OB’s all come with a fuel gauge for the diesel tank.
Click to expand...
Excellent news. Now I wonder if the same has been done for the 2023 model R25/OB NW Edition. Let's hope so.

Where on the current R27/OB models is the Webasto diesel tank's fuel gauge located?
 
As an aside, Baz mentioned having to run the heater on low because it can get very hot in the cabin. It is always good practice to run it on high for a a few minutes and then shut down while on high. This will burn off any built up coke residue and save you heartache down the road.
 
Yes Mike/knotflying. I agree.
 
baz":2vl2u1ni said:
Submariner":2vl2u1ni said:
The 2021 and newer r27-OB’s all come with a fuel gauge for the diesel tank.
Click to expand...
Excellent news. Now I wonder if the same has been done for the 2023 model R25/OB NW Edition. Let's hope so.

Where on the current R27/OB models is the Webasto diesel tank's fuel gauge located?
Click to expand...

I checked in with Andrew about the Webasto's diesel fuel tank level gauge for the 2023 R25/OB NW Edition and was told "...I believe it should have a gauge.". This is good news for me. 🙂
 
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