Water heater bypass valve

[JamieGeek]

Originally Posted by sforl

Jamie please educate me! To diagnose my problem the service rep had me turn on the hot water in both the kitchen and the bath. So I guess that would produce more flow through the system. Right? That seemed to make everything work properly! He then told me to increase the PSI on the Valtera regulator to between 60-80! Which I did not do. I did increase it to 54psi which seemed to work.
So how do I increase the flow without raising the water pressure so high?
Thanks

LOL well I'm no expert on plumbing, water flow, or even hydrodynamics for that matter

Given your description it does sound like flow rate is more important than pressure. My guess would be that he had you increase the regulator pressure as a way to get the flow rate up (by "forcing" more water through the system). You may find you get more water through the system by simply removing the regulator all together (mentioned earlier that some regulators will reduce the water flow rate).

[SuperD]

Tankless water heaters have a series of coil or pipes to absorb heat quickly from the flame. The faster the water flows the less time it has to absorb heat. I disagree with the person at Girard, the tankless heater depends more on flow rate than it does on pressure. I've used many tankless heaters in 3rd world countries, if you turn the water up its cold, turn it down its hot, pressure stays the same, only the flow rate changes. Pretty simple. Turning up the pressure allows more force to push the water thru the restrictions which increased the flow rate. Your MH should be able to take 60 psi with no problems, most are tested at 80-100 psi.

Hope this all makes sense and I haven't confused you more, if so please say so. I don't mind questions, I ask them all the time! Lol

[JamieGeek]

Originally Posted by SuperD

Tankless water heaters have a series or coil of pipes to absorb heat quickly from the flame. The faster the water flows the less time it has to absorb heat. I disagree with the person at Girard, the tankless heater depends more on flow rate than it does on pressure. I've used many tankless heaters in 3rd world countries, if you turn the water up its cold, turn it down its hot, pressure stays the same, only the flow rate changes. Pretty simple

That maybe the case but I'm guessing that this tankless heater has a "minimum flow" switch and doesn't come on until the flow hits that rate (which, it would appear, is slower than a single faucet).

[sforl]

SuperD the Girard rep suggested I do one or the other. Increase the pressure or remove the pressure regulator. I guess he thinks the regulator may be adversely affecting the flow??? So you're saying that increasing the pressure was the correct thing to do?
I'm glad you guys don't mind questions because I have millions of them!

[SuperD]

I would maybe increase the pressure just a little more, you are probably right on the tipping point one way or the other. Girard rep was right and wrong at the same time.

[JamieGeek]

Originally Posted by sforl

I'm glad you guys don't mind questions because I have millions of them!

Fire away...that is what the forums are for. Someone will have an answer or know a route to take or even dig into something on their coach to see if its similar.

Part of the fun of having the RV..tinkering/fixing/learning/etc.

[bevedfelker]

I had researched this tankless water heater extensively to include it in my Axis/Vegas Crowd sourced Owners' Manual. Here is a link to the discussion I posted to the forum about the UNIQUE quality of this hot water heater -- that being you don't control the water temperature by adjusting the flow of COLD water to mix with the hot. You adjust the flow of the HOT water to control its temperature.

Here is a quote from my previous post:
"In reading the owners' manual adjusting water temperature in this water heater is counter intuitive to everything we do in regulating the temperature of hot water at a tap. Basically conventional wisdom says regulate the temperature by adjusting the amount of COLD water being mixed at the tap. In terms of this tankless hot water heater -- that is EXACTLY the wrong way to adjust the temperature.

Here is what the Girard GSWH-1 says about the operation of their system and how to increase and/or decrease hot water temperature at the tap or shower head:

"The Girard Products model GSWH-1 is a new 'induced-draft', tankless water heater designed specifically for Recreation Vehicles (RV). Its configuration and size are consistent with the tank based RV water heaters currently in use and is designed for OEM's and after market use by the RV industry. A main feature of the GSWH-1 is a Dual BTU burner, which is set by the Mode Switch to either HIGH (34,000 BTUs) or LOW (27,000 BTUs). The incoming water temperature will raise 40°- 60° (F) based on water flow.

A tankless water heater heats water while it is being used i.e., on demand. The output temperature of the water depends on the temperature of the inlet water AND the amount of hot water that is drawn."

In addition the manual says the Girard Tankless Water Heater operates at 40 - 60 psi.

Here is the link to my previous post: http://www.thorforums.com/forums/f10...ater-6809.html


Here is a link to the Girard Owners' Manual: https://www.manualslib.com/manual/94...-1.html#manual



If you have this tankless water heater you can save yourself a lot of grief by downloading it. Printing it. And reading it (like who reads owners manuals). I'm not trying to insult anyone's intelligence -- but -- this water heater does not operate like the tanked water heater we have in our RVs or home.

[bevedfelker]

Here is a copy of the Girard Tankless Water Heater Owner's Manual.

[SuperD]

Everything Ed is saying is exactly what I said, the temperature of the water will depend on the flow. With less flow the water stays in the heater longer and absorbs more heat from the burner. Turn up the flow and water stays in the heater less time and absorbs less heat, you get cooler water. In reality you may not need to, or want to, turn on the cold faucet, you can adjust the temperature by regulating the flow with the hot water faucet. Down side, you may not get a strong shower!

[sforl]

In my case the only way I could get hot water was to run hot water in both the kitchen and the bath. With the increased flow I could hear the unit igniter fire and the digital display showed the flame icon and a fan icon. That had not happened before.
I was aware of using only hot water and setting the desired temp. I was also aware of regulating the temp via water flow. What I don't understand still is how to increase the water flow. Am I always going to have to run both the kitchen and bath faucets when I want hot water? What about the shower?
I'm confused about the water pressure regulator. Are they a good thing or a bad thing when you have these types water heaters?
The more I learn... the less I know!

[SuperD]

You should always have a pressure regulator to protect your coach. I've seen campgrounds with as much as a 110 psi, pretty much guaranteed to blow a water line. My father in law forgot to put the regulator on his coach once, I spent the better part of two days fixing blown fittings.

RVs have small water lines that aren't conducive to good flow. Your regulator is not the problem. The heater obviously demands more flow to ignite than one faucet can put out. I would read the manual throughly to see if there is an adjustment that will allow it to kick on with a lower flow, if not you may unfortunately need to open more that one faucet to get a hot shower.

As a former engineer, and based on your responses, I would have to say someone didn't think the process out to well. Tankless heaters are relatively new to the Rv industry, seems like a little more R&D needs to be done to address the flow issue.

Maybe a call to Girard and an explanation of your problem might help. Just turning up the pressure isn't going to solve the problem, you could get higher flow in a campground, but ask them about when you are using your water pump, it's not going to put out anywhere near the pressure or flow your heater seems to need. I will be curious to hear their response.

Other than just explaining the basics I apologize for not being more helpful!!!

[JamieGeek]

Is there any hysteresis to the flow switch? (e.g. it takes two faucets to get the unit to turn on, but once on the extra faucet can be turned off and the slower flow will keep the unit running)? A quick read of the manual seems to indicate that.

Something to try at any rate: Turn on two faucets to get it running, then turn one off and see if it stays on heating the water.

[ctpres]

Sforl: If you just want to increase flow without increasing pressure - replace plastic PEC fittings with brass. The ID of brass fittings is much larger. My mod to-do includes that and a manifold. I estimate whole project at under $100 including crimp tool. Did not read every post - did you remove the shower flow restrictor?

[SuperD]

Originally Posted by ctpres

Sforl: If you just want to increase flow without increasing pressure - replace plastic PEC fittings with brass. The ID of brass fittings is much larger. My mod to-do includes that and a manifold. I estimate whole project at under $100 including crimp tool. Did not read every post - did you remove the shower flow restrictor?

Chuck, great ideas! If you have time could you share a how-to, and maybe pictures, bet it would helpful to a lot of people!

Could you recommend a nice Rv park in Houston near NASA, went there once but only for one day, would like to spend 3-4 days. Thanks!!!

[ctpres]

Originally Posted by SuperD

Chuck, great ideas! If you have time could you share a how-to, and maybe pictures, bet it would helpful to a lot of people!

Could you recommend a nice Rv park in Houston near NASA, went there once but only for one day, would like to spend 3-4 days. Thanks!!!

My to-do list is VERY long now. Plumbing overhaul near bottom but I did buy the tool https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 and a bunch of fittings - sorry!
Good rating and lots of reviews - Galveston Bay RV Resort & Marina. About thirty parks in that area.

[sforl]

ctpres
" did you remove the shower flow restrictor? "
What shower flow restrictor?

[ctpres]

Originally Posted by sforl

ctpres
" did you remove the shower flow restrictor? "
What shower flow restrictor?

Remove shower head at end of hose. Look at hole in end of handle. If you see a 1/8 inch or so size hole - that is a water flow restrictor. It reduces water flow thru shower head to conserve water. Usually it can be removed - if not - should be safe to enlarge hole. Camp Happy!

[CAC Windsport]

SFORI, my Thor has the access panel under the kitchen sink. There is a wood panel with some screws holding it in place. The hot water tank and valve is located behind that panel