Girard Tankless Water Flow Issues

memphis02 · 08-31-2020, 07:44 AM

In my '14 Seneca, where I have a Girard GSWH-1M tankless instant water heater, I've been experiencing very low flow at all faucets. I get hot water (sometimes) out of them all but the rate is roughly 20-30% of what I get from the respective cold side.

If I turn off the unit and only run water through it, I hear a rattling noise coming out of the flow sensor which is just before the heater assy. so my thoughts are that there might be something wrong with it, but as it correctly senses flow, I'm just not sure... -Has anyone had that flow sensor apart and know if there's something in it that might be able to break that would cause a restriction?

I am trying to avoid taking the entire unit out since I'm not sure if there's any point in doing so. It seems like I read, somewhere, that there might be a strainer ahead of the incoming water, but without knowing for sure, wasn't going to go ripping things apart for no reason.

Greyhawk01 · 08-31-2020, 08:52 AM

Get some pex fittings from the hardware store to bypass the heater then see if your water pressure is restored.

Greyhawk01 · 08-31-2020, 08:55 AM

The water runs thru a coil that is heated not much else can go wrong other then a clog in the coil or maybe it got kinked or damaged somehow.

Greyhawk01 · 08-31-2020, 08:58 AM

Was it something that happened suddenly or over time

memphis02 · 08-31-2020, 09:17 AM

If it did it over time, I didn't notice it. We've had our rig up for the year since March. -The last two or three times out, we have had the issue. I thought it was a pressure problem because the factory pump died, last year and I replaced it with an old spare that was about .2gpm less than factory. I replaced the old spare with a new remco 5.3gpm; suffice it to say, it's not a pump issue. :-)

There's really no way to bypass the tankless without pulling the whole water heater out, as far as I can tell.

Greyhawk01 · 08-31-2020, 09:26 AM

Im not sure if your seneca is different from my greyhawk but inside of the coach just below the refrigerator is a large grill / vent. I just removed that and was able to access the back of the water heater. The I just looped the inlet and outlet lines to bypass it.

memphis02 · 08-31-2020, 10:00 AM

Unfortunately, on my 2014 model, the HWH is in the driver's side rear compartment. I believe, on newer models, there is an access door installed by the factory, however, mine is completely sealed in the bay. Of course every single screwhead is stripped out by the jackleg who installed it, so taking it out is going to be F-U-N.
My local service tech, just from talking over the phone, said he thought it sounded like a check-valve that has broken.

Any Seneca owners know if such a check-valve exists on the back side of the girard?

GCAT9110 · 08-31-2020, 10:07 AM

I have one on my 2015 37TS and so far so good. With that said, On demand water heaters can suffer from hard water or calcium build up in the coils/core which will reduce flow. I have seen this in residential applications and cleaning the coils will fix the problems. That may be easier said than done??

memphis02 · 08-31-2020, 12:11 PM

After talking to Girard and a few local resources, I'm going to start with taking the flow sensor out. I'm going to try to run some water through it with the flow sensor removed to see if the rate is any different versus going through the heating loop.

RVermont · 08-31-2020, 01:22 PM

On my truma unit this spring I had an issue with the sensor not working. I pulled the unit out and removed the sensor and soaked it in vinegar and the then blew air through it. The unit worked correctly after that for a couple of weeks but failed again. By this time I had received the decalcification tablets from truma and ran the process. I have not had any issues since May so I believe it was calcium build up blocking the sensor. Not sure if girard has a procedure or not but it is worth looking into.

JimD · 08-31-2020, 01:22 PM

My old Girard, which I yanked in favor of a tank model, had a flow control valve on the back. It allows reduced flow to make the water coming out hotter. Maybe there is a buildup or restriction in that valve.

memphis02 · 08-31-2020, 04:02 PM

Thanks for the tip, Jim! I am going over to the barn and have resolved to remove the stripped out screws and see just what's what behind it. I'll post pics when I get into it.

memphis02 · 09-01-2020, 07:12 AM

I pulled the water heater out, last night. Unfortunately, I did not find a flow control valve, which would have made it too easy. This view is looking from the rear of the coach toward the front, top down. I'm really baffled how they got rigid plumbing connected to this... I was very concerned I was going to tear things up just sliding the HWH to the front of the opening.
I have the flow sensor ordered and that will be my next point of attack.

Puddle Pirate · 09-01-2020, 07:32 AM

I had the same type of problem, after digging, I found a line that was bent, kinked ---from the factory-straighten it out---no more problems ---the unit is working great--love the long showers when hooked up---

memphis02 · 09-03-2020, 10:33 AM

I received the replacement sensor, yesterday. I found this pretty interesting, considering I had been told that "there are no moving parts" inside the sensor.
In actuality, there is a piece inside that when flow is applied would float up to engage the magnetic sensor. It would be incredibly easy for a buildup of calcium or anything else to clog this VERY narrow passage and restrict flow.

Crossingover · 09-03-2020, 12:23 PM

Waiting patiently for the pics of the removed sensor . . . thanks for posting this.

memphis02 · 09-03-2020, 12:29 PM

Quote:

Originally Posted by Crossingover

Waiting patiently for the pics of the removed sensor . . . thanks for posting this.

Depending on how cold of a shower I (DW) have to take over the next few days (we're leaving tomorrow for a 7-day trip). Pics may be very soon or might not be until next weekend of the removed sensor. ;-)

memphis02 · 09-12-2020, 09:01 AM

As promised, here are the results of my repair!

My problem were actually 2:
The reason my heater has been noisy to the point that neighbors camped next to us complained, was that the blower fan was about 1/2" out of balance. I took the exhaust shroud off and was able to bend the fan back into balance and it is now quiet to the point that we don't know it's on; which is what I suspect the rest of you have always had, however, since we bought our Seneca, it was loud enough to be heard land disturb normal conversation at over 100' away.

The original issue of low flow was, indeed the sensor; however the fitting had a screen in it and it was almost completely stopped up just before the sensor; and the sensor, itself, was also covered in crudd. -This surprised me because I use 5 micron water filters.

The sensor was not easy to remove. It is fitted to a 90 that I'm reasonably sure was installed by the Incredible Hulk. It was easier to take the entire HWH unit out of the camper, remove the retaining plate so the sensor and 90 could come out, then put it in a bench vice and use all of my 215lbs & a 3/4" wrench to break it loose.

New sensor installed and flow on Hot and Cold are, now, identical.

Crossingover · 09-13-2020, 01:42 PM

Do you think it is possible to backflush through the HWH drain connection to push some of the collected sediment etc back out through the HWH cold water inlet and eventually out of the main water inlet on the valve panel?

hikerjohn7 · 09-16-2020, 01:46 PM

Quote:

Originally Posted by memphis02

In my '14 Seneca, where I have a Girard GSWH-1M tankless instant water heater, I've been experiencing very low flow at all faucets. I get hot water (sometimes) out of them all but the rate is roughly 20-30% of what I get from the respective cold side.

If I turn off the unit and only run water through it, I hear a rattling noise coming out of the flow sensor which is just before the heater assy. so my thoughts are that there might be something wrong with it, but as it correctly senses flow, I'm just not sure... -Has anyone had that flow sensor apart and know if there's something in it that might be able to break that would cause a restriction?

I am trying to avoid taking the entire unit out since I'm not sure if there's any point in doing so. It seems like I read, somewhere, that there might be a strainer ahead of the incoming water, but without knowing for sure, wasn't going to go ripping things apart for no reason.

I learned the the RV manufacturers are very careless about ensuring their products are clear of manufacturing debris. I had one faucet full of manufacturing chips that was blocking the water. A rattling sound could be debris.

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