Tankless Water Heater

[twadd10]

So this may seem like a crazy question, but have any of you guys with these tankless heaters found the sweet spot on your water pressure?

I have just your everyday cheap water regulator but with it on I don't get enough pressure/flow to kick the water heater on. I'm assuming I need to get an adjustable water pressure regulator. Thanks

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[sennister]

Originally Posted by twadd10

So this may seem like a crazy question, but have any of you guys with these tankless heaters found the sweet spot on your water pressure?

I have just your everyday cheap water regulator but with it on I don't get enough pressure/flow to kick the water heater on. I'm assuming I need to get an adjustable water pressure regulator. Thanks

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I don't have a tankless system in the RV but I have one in my house. They don't work off of pressure as much as flow rate. I am on a private well and septic at my house and my well uses a 40/60 switch so my water pressure is somewhere in the 40-60psi range. This really doesn't matter much as the water heater senses flow and once it crosses the threashold it will activate. A lot of people in RVs go with these super low flow heads on the showers which is great because you have limited water and grey tank capacity but if they restrict flow too much, they won't allow the water heater to kick in.

Another may be to lower the temp setting on the tankless unit if it is adjustable like the home units. If you have it set to 160f (probably doesn't got that high) then you are going to barely have the hot side on and mix a lot of cold in with it so the water heater will see little to no flow across it and may not kick in or it will kick in and out. If you take your showers at 110F and have it set to that now you will pull almost 100% of your flow through the heater and mix in little to no cold water. In the end you are using the same amount of water and sending the same amount down the drain.

I just don't know if these are adjustable like the home units. Mine has a remote panel that I installed next to the thermostat in the house which is in our main hall so I can adjust the temp on the fly if I want to do something with hotter water than my normal 120F setting. For instance I have valves I can throw to route hot water out to a water bib. Then I hook my pressure washer up to it and can run hot water through the pressure washer to really clean stuff outside. I do have to throw a safety override on the unit to get above 130F or so though.

[Mopar_Earl]

All water pressure regulators will cause a restriction and lower your flow. Especially cheap ones and unadjustable ones. If your pressure is good, don't use the regulator, it will just reduced flow.

I heard if you use Body Spa Oxygenics Shower head it does wonders with the tankless water heaters. We have one and it's a huge improvement over the standard shower head. We love it. We have a tanked heater.


Earl

[twadd10]

Thank you for that info. It does have a thermostat inside the unit to adjust the temperature, I think max is 124F.


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[NorthPoint5r]

The flow setting is way low on these units to kick on the heat. I found that even when connected to a low pressure water source kicking on the water pump helps get the heat going. Or just waste water and heat and have two water sources on at once to get flow up.

[twadd10]

Originally Posted by Mopar_Earl

All water pressure regulators will cause a restriction and lower your flow. Especially cheap ones and unadjustable ones. If your pressure is good, don't use the regulator, it will just reduced flow.

I heard if you use Body Spa Oxygenics Shower head it does wonders with the tankless water heaters. We have one and it's a huge improvement over the standard shower head. We love it. We have a tanked heater.


Earl

Thanks Earl I may have to try one of those shower heads!

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[twadd10]

Does anyone know what the water systems (plumbing) in these units are rated to?

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[sennister]

Originally Posted by NorthPoint5r

The flow setting is way low on these units to kick on the heat. I found that even when connected to a low pressure water source kicking on the water pump helps get the heat going. Or just waste water and heat and have two water sources on at once to get flow up.

So is the temp fixed in the unit and not adjustable? I know that with the tank systems like my Atwood, it isn't adjustable but I have seen some people have replaced the thermostat with one set at a different temp. I could see that to keep costs down they may have them set to a fixed temp but that isn't ideal with a tankless system. As I mentioned I have a remote control panel on mine so I can control it from upstairs but it is optional. If I didn't have that I would have to go open up a panel on the unit and set the temp via jumpers. That might be an option if one were to look up the owner's manual. Since I don't have one I don't know who makes them or what model is normally put in them.

Based on my experience, lowering the output temp will increase the flow through the unit. That and most complaints I see about tankless systems come from people that are used to tank based systems and try and use them like a tank system. Of course there is also the issue of properly installing and sizing a unit. If cold weather camping and your cold water is near freezing and you are pushing the limits of the flow rate, you are not going to get very hot water. The water is in the heat exchanger for only so long depending on flow rates. Because of this they can only impact a certain amount of temp change or temp delta based on the capacity of the heat exchanger and the BTU rating of the unit. If your cold water is at 70F, your unit is rated for a delta of 45F and you are calling for 110F you are good. However if you are pulling from a FW tank and it is early spring so that water is 40F and you still have a delta of 45F calling for 110F, well you are only going to get 85F water out of the unit on full hot. You can slow your flow so it is in the heat exchanger longer but if you slow it too much the unit will cut off. These are all just for an example numbers but the type of math I did when I was sizing a unit for our house. Granted my water temps are pretty much the same year round so I wasn't dealing with the inlet water temp fluctuations that are possible with a unit installed in a camper. I guess if you have the arctic package with the tank heater you could run that to try and get your inlet temps up a bit.

[sennister]

Originally Posted by twadd10

Thank you for that info. It does have a thermostat inside the unit to adjust the temperature, I think max is 124F.


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It is good that they let you adjust it. Personally I take showers around 110F. I don't think I go much higher but we also have several shower heads (standard, cloud and body sprayers) so I don't have a flow problem. In fact I had to run 1" water lines to the shower.

So try and turn down the temp on the water heater to 110 or so. This will increase the flow through the heater and help stabilize it.

Also if you happen to know the make/model I would be interested in looking up the specs on it. To get the best out of a tankless system you really need to understand flow rates, temp deltas and usage. In my case I had to go with a really bit 199,000 BTU unit because of my high flow rate and pretty cold ground water up here in MN. It was the only way to hit my deltas.

Another variable with putting these units in RVs is that my home one has a high altitude mode. I didn't have to turn it on and it isn't like my house is moving but it is another factor that needs to be considered as you move your RV around place to place if you get up in the mountains.

[sennister]

Originally Posted by twadd10

Does anyone know what the water systems (plumbing) in these units are rated to?

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I guess what are you asking? Temp rating of the heater, the delta, flow rates and such that I have been mentioning? Or how cold of weather conditions you can deal with before needing to winterize?

[Mopar_Earl]

Believe he means what pressure is the water system rated for. Which I believe most are 60 or higher now.


Earl

[sennister]

I looked up the Pinnacle owner's manual for 2017 and there isn't much info.

They don't mention the make or model and tell you to reference it for more information. It does mention a couple bits that are good. They mention the 65F inlet temp for your water (cold water). If it is colder than that you need to adjust the flame with the GMC. They don't go into details on the delta but it looks to be around 40F of course as I said flow rate dictates this. Also there was another good bit of info. There is a hard limit around 131F. So if you are calling for high heat (close to 130F) like you would set it on a tank based system at home but you have one of these super restrictive shower heads and running a lower flow rate you might hit this limit where it shuts down. This is going to cause surging and why I mentioned to try and turn down the temp to a setting closer to what you actually want at the point of use. That is like my home unit. It won't let me set it above somewhere in the 130F range. However if I open the panel I can take the safety off with a jumper setting because my unit can be used as a boiler in a floor heat system where you might need higher temps. In this case hitting that high temp limit is probably only an issue in the summer where you might have forgotten you set the heater to high flame, you now maybe are pulling from a FW tank that is much warmer than 65F so the inlet temp is much warmer. Combine that with a low flow rate which increases the delta from what is probably designed for around 45F but now is up into the 60s and you could shoot past the 131F internal safety where it cuts out.

TANKLESS WATER HEATER (If So Equipped)
Your motor home may be equipped with a tankless water heater. The tankless water heater uses less LP Gas than storage tank model water heaters since it only uses energy when hot water is demanded. There is no pilot light to burn when no hot water is needed. The tankless water heater supplies an unlimited supply of hot water on demand (once lines are purged of standing water). As hot water is used, the cold water enters the heater. A water flow sensor detects the flowing water and automatically ignites the burner. Water circulates through the heat exchanger and is heated to the set temperature. When the tap is closed, the unit shuts down.

The tankless water heater does not require an anode rod to prevent corrosion, or a by-pass valve for winterizing. It is not affected by high altitudes. The output temperature of the water depends on the temperature of the inlet water AND the amount of hot water that is drawn. If the inlet water temperature is over 65ºF the tankless water heater will generate water in the range of 105°F to 120°F (on Low flame) depending on the water flow selected by the user.

Operating Tips

Purge air out of ALL hot and cold water lines.

Open the water heater door and turn the power switch “ON”.

Set GMC (gas modulator dial) to appropriate setting.

Normal weather – set dial to the middle area.

Extreme cold weather – set dial to the extreme right (large flame).

Extreme hot weather – set dial to the extreme left (small flame).

Open hot water faucet to a medium water flow. It may take a few seconds for the water to travel from the water heater to the faucet.

To reduce temperature:

Turn GMC dial “counter-clockwise”.

Increase hot water flow.

Gradually add cold water.

To increase temperature:

Turn GMC dial “clockwise”. NOTE: Use caution not to increase the dial too
much which could cause the hot water temperature to rise to the point the water heater “limits’ and turns OFF the flame (flame shut off is approximately 131° F).

Reduce hot water flow.
For Additional Information
For detailed operating information refer to the manufacturer’s owner’s manual included in
the Warranty Packet.

[sennister]

Not sure if the Pinnacle uses the Girard tankless system but I found this post which indicated Jayco was using them in other units.

http://www.jaycoowners.com/forums/f1...urne-5105.html

I went to the website and I don't know a model number but found this manual.

https://cdn.shopify.com/s/files/1/12...38916666812149

It has some interesting information starting on page 11. Then on page 12 is a notice that should be read. They mention the safety cutoff at 125F. They also were talking about what I said in that by reducing the flow it increases the temp. This is because the water is in the heat exchanger longer and this increases the delta or change in temp from inlet temp to output temp. They are saying to adjust the temp by turning on the hot water if it is too hot, turn up the hot water which increases flow rate and cools the water. This would be the opposite of what most people used to a tank based system would do. They would turn down the hot and maybe introduce cold which then could cause the system to further heat up and hit the 125F limit and cut out.

It doesn't really mention being able to adjust the temp of the unit or at least this one didn't other models probably do as mentioned above.

Some other specs were the 65F inlet temp as kind of where they want it to be. Of course a FW tank in cold weather may be much lower than this and impact things. As for pressure they mentioned 45PSI or greater. Now this is the particular model that I found a manual on which may be different than the one you have but I would guess most are going to be around this rating requirement. As I mentioned, flow and inlet temps are normally more important than pressure though.

[twadd10]

Originally Posted by sennister

Not sure if the Pinnacle uses the Girard tankless system but I found this post which indicated Jayco was using them in other units.

http://www.jaycoowners.com/forums/f1...urne-5105.html

I went to the website and I don't know a model number but found this manual.

https://cdn.shopify.com/s/files/1/12...38916666812149

It has some interesting information starting on page 11. Then on page 12 is a notice that should be read. They mention the safety cutoff at 125F. They also were talking about what I said in that by reducing the flow it increases the temp. This is because the water is in the heat exchanger longer and this increases the delta or change in temp from inlet temp to output temp. They are saying to adjust the temp by turning on the hot water if it is too hot, turn up the hot water which increases flow rate and cools the water. This would be the opposite of what most people used to a tank based system would do. They would turn down the hot and maybe introduce cold which then could cause the system to further heat up and hit the 125F limit and cut out.

It doesn't really mention being able to adjust the temp of the unit or at least this one didn't other models probably do as mentioned above.

Some other specs were the 65F inlet temp as kind of where they want it to be. Of course a FW tank in cold weather may be much lower than this and impact things. As for pressure they mentioned 45PSI or greater. Now this is the particular model that I found a manual on which may be different than the one you have but I would guess most are going to be around this rating requirement. As I mentioned, flow and inlet temps are normally more important than pressure though.

Wow. Thanks for all the info!! I'm pretty sure mine has the Girard gswh-2. I'm gonna use some of your advice and see how things work out.

Yeah earlier I was asking about the plumbing of these newer rvs, asking what water pressure they are rated for. Earl said 60+ psi, which I think I've heard that before. Just wasn't sure how safe it is to just hook up the water without some type of regulator. Thanks

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[sennister]

Originally Posted by twadd10

Wow. Thanks for all the info!! I'm pretty sure mine has the Girard gswh-2. I'm gonna use some of your advice and see how things work out.

Yeah earlier I was asking about the plumbing of these newer rvs, asking what water pressure they are rated for. Earl said 60+ psi, which I think I've heard that before. Just wasn't sure how safe it is to just hook up the water without some type of regulator. Thanks

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All the manuals are here.

https://greenrvproducts.com/pages/owner

This looks like the manual for your water heater.

https://cdn.shopify.com/s/files/1/12...38094769452505

Starting on page 12 they talk operation.

Key points:

45PSI or greater for water pressure.
42,000 BTU water heater
They recommended 115F for the temp setting. Pretty close to the 110F I mentioned.
Pg 14 mentioned an optional water control valve to adjust flow. This could be used to slow the flow when inlet water temp is cold (below 65F) or like with the other one this can be done by turning down the flow on the hot side.
Looks like 124F is the highest temp you can set it to but as mentioned lower may be better.

One thing I didn't see was any mention about the flame height control that the other one mentioned. This seems like a newer one that must be automatic.