2017 Jayco Greyhawk 29MV - Water heater issue

Phazewun · 12-26-2021, 04:45 PM

Good afternoon hoping someone can give me some advice here, we purchased this motorhome about 2 years ago and have basically never had hot water through the girard gswh-2 tankless water heater. Today i decided to dig into it to try and find the problem and found out that the heater is only NOT working when its being supplied by the onboard water pump. When i connect to city water everything works great and has no issues.

Has anyone experienced this problem before ? A few people said to bypass the water pressure sensor but i havent been able to find any information about doing that.

Any help would be appreciated.

CAG · 12-26-2021, 05:12 PM

I tried the search bar (in gold) at the top of the page and did not find much although there are previous threads. I then tried my Internet search engine and found this. The is more if you do a Google search.

https://www.forestriverforums.com/fo...is-229762.html

Phazewun · 12-26-2021, 05:13 PM

thats for some replacement chairs.

JimD · 12-26-2021, 06:24 PM

I had the the Girard tankless in my 2017 Greyhawk and absolutely hated it. I didn't have any problems with the onboard pump, which is what we used mostly, but it just sucked overall at supplying hot water unless you wasted a lot of water by opening the faucets to have high enough water flow to get it going. Showers were the worst.

Anyway, I have attached the manual for the unit. Maybe it will be of help. Since I swapped my unit out for a tank model I no longer have any hot water issues. If you dry camp a lot these tankless units waste a lot of water.

Phazewun · 12-26-2021, 06:39 PM

Once you got the flow going were you able to shut off the shower and turn it back on and still have hot water ?

JimD · 12-26-2021, 07:00 PM

The best way we found to set the shower temp was to use hot water only and set the display temp to something comfortable (I think is was just over 100). Then we used the head to start and stop the flow. When the flow was stopped the water heater would shut down and when the flow started again it would fire back up. Unfortunately you would get a short burst of cold water come through.

I suppose the water heater would work just fine if you had full hookups because you wouldn't have to shut the water off. We mostly dry camp and have to be warry of wasting water and also not filling up the gray tank.

Another thing I didn't like was washing dishes. When rinsing I use a very low flow of water and it would not turn on the unit. The hot water for washing was mostly OK but I can tell you that having a tank model will burn your skin off with its hot water capability. Dishes and shower are no longer a problem for us.

Many people love tankless units. They do supply unlimited hot water as long as you keep it flowing hard enough. A tank model will run out with a very long shower.

Phazewun · 12-26-2021, 07:07 PM

thank you i will try that, right now if i turn on the water pump and just run 1 sink i get 0 hot water. Going to try and turn everything on to increase the flow.

Parrott · 12-26-2021, 08:31 PM

Check your strainer filter on the water pump to make sure you are getting full flow. As was said, for boondocking not the best. We like ours because I don’t have to wait after my wife finishes her shower to take mine. I found I can get the water hotter by turning down the flow at the faucet. There is also a flow knob on the back of the water heater you can adjust. Check to make sure yours is all the way open.

Phazewun · 12-26-2021, 08:57 PM

Where is the strainer filter located ?

Parrott · 12-26-2021, 09:17 PM

Quote:

Originally Posted by Phazewun

Where is the strainer filter located ?

It’s located on the inlet side of your pump.

Phazewun · 12-26-2021, 09:24 PM

hmm alright i gotta find where that is.

pconroy · 12-27-2021, 12:30 AM

Quote:

Originally Posted by Phazewun

found out that the heater is only NOT working when its being supplied by the onboard water pump. When i connect to city water everything works great and has no issues.

we usually have the opposite issue. I rarely shower from the city water, instead I fill the tank and then turn on the pump.

the buggers are sensitive to flow. Not enough and they won't heat.

when you pump from the tank, does the heater blower start at all?

gprapim · 12-27-2021, 07:56 AM

Quote:

Originally Posted by Phazewun

Good afternoon hoping someone can give me some advice here, we purchased this motorhome about 2 years ago and have basically never had hot water through the girard gswh-2 tankless water heater. Today i decided to dig into it to try and find the problem and found out that the heater is only NOT working when its being supplied by the onboard water pump. When i connect to city water everything works great and has no issues.

Has anyone experienced this problem before ? A few people said to bypass the water pressure sensor but i havent been able to find any information about doing that.

Any help would be appreciated.

Another thing you might consider checking out. I had the same trouble with just my bathroom faucet, not giving me hot water, while the kitchen faucet had hot water. I changed out the aerator on the bathroom faucet to a higher flowing one, and bingo, I had hot water. Since the tankless heater needs a certain flow of water to work, this took care of my problem. Aerators can be purchased from any hardware store and can be had with different flow rates. If you are getting hot water while on city connection, maybe you are not getting enough flow to get the tankless unit working when on water pump. This just might be your problem. It was for me.

Dave T WA State · 01-01-2022, 02:34 PM

Phazewun: I responded to another question earlier about inverter location. This will tell you how to find your water pump:
I have a 2015 Grayhawk "C". Not sure about your rig's design. But my inverter is mounted in the cabinet under the bed riser, which puts it 'behind' the breaker and fuse panel.
To get to it, extend the slide. Take the mattress off the bed. Then raise the hinged plywood surface the mattress sits on...it should stay up propped against the upper cabinets.
On the top of the bed riser cabinet, you will see a plywood cover which is held down by screws (square drive or Phillips). Remove that cover.
The Inverter is mounted beneath the cover. Don't be alarmed by the spaghetti bowl of wiring you'll see!
Note....there is a second covered area to the right of this space. That is where the manifold plumbing is located, including the fresh water pump.
When I reinstalled these covers, rather than putting the screws back in, I made a 'hinge' using Duct tape.

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