Propane tankless water heater

[WinterDeere]

I live in a big house and already wait for hot water. So waiting for a tankless heater won't bug me. I already looked into a recirc. system and nixed the idea. Too much energy wasted.
Eric

I think the idea behind the recirc is to schedule it to have things pre-heated prior to your windows of highest usage. So, energy loss may not be as high as you expect.

Besides... you bought the big house! You can afford the fuel.

When we bought the current place, I asked the prior owner what he spent on heating oil, as it's a big and very old house. He looks at the floor, rubs his chin a moment, then looks up at me and says, "to be honest with you, I have no idea." He owned an oil company, so despite signing the delivery receipts, he never actually looked at the cost.

 

[zzvyb6]

I have a Rheem on natural gas. Mounted 4 feet directly under the shower head. Water temp limited to 120 degrees by law (scalded baby syndrome). Takes about 4 seconds to go from cold to really hot.

Easily flushed periodically using bypass valves to connect a small sump pump pulling vinegar out of a bucket, flowing it into the tank, and exiting it back into the bucket. Run for 10 minutes and reset the bypass valves.

 

[ponytug]

Did a bit of hunting on these pumps. Lots of no-name crap out there, but the major brands all seem to include a timer I wouldn’t want or need. Any recommendations for a pump with thermostat only, and no timer? I’d rather manage timing by my home automation system, than have another independent timer to keep on schedule though every power outage.

FWIW: Mine have also had a timer, but I have mine set up on a separate programmable 24hr week long lamp timer for awake/sleep (on/off), and I use the built in timer to run it on a 50% duty cycle.

All the best,

Peter

 

[HawkinsHollow]

@WinterDeere

AquaMotion AMH3K-7N On-Demand Under Sink Hot Water Recirculation Pump Kit

HotOne under sink circulator designed to deliver hot water instantly

www.totalhomesupply.com

 

[mikester]

A hot water tap about 15 feet from the hot water heater takes 40 seconds to get hot water, that is unacceptable in my opinion.

LOL

I'm on well and septic meaning that during a power failure I don't have potable water - or flush toilets unless I get buckets of water from my creek half a mile out in the back 40. Uphill both ways.

My neighbor's 40 year old septic bed failed and started backing up into the house. He had to wait 3 weeks to get it replaced meaning no showers, no dishwasher, no laundry and he had to spend $300 to get his tank pumped out every time it got full during his wait.

When your sanitary water system doesn't work 40 seconds waiting on hot water will seem trivial.

 

[Sigarms]

I put in a tankless 2 years ago that replaced my standing LP power vented water heater. No regrets and added some extra breathing space in my mechanical room that shares a freezer, 2 HVAC systems with a dehumidifier.

Some thoughts (which may have already been addressed as I haven't read the entire thread)...

1 - if you have harder than normal water, ensure you clean the heat exchanger annually with vinegar. That will go along way over time.

2 - If you want quicker than normal hot water at longer lengths per a water source, install a mini circulator pump at the furthest point. This will reduce wait times for hot water.

3 - Although technically a tankless should save you money, the reality is it may not. Because you won't run out of hot water, you may end up using the tankless more than a standard standing water heater where you will stop using it when you run out of hot water from the older tank.

4 - MOST IMPORTANT - ensure you know what kind of flow rate you are going to need with the family in the home. If you only run one shower or run a dishwasher or anything else by itself, chances are you should be OK. The issue is depending on how many water sources are used at the same time, you may not get the hot water you're expecting.

A quick search online and I found this on the topic. Don't know the source, but seems to hit on the basic points on flow rate

Determining GPM for Your Tankless Water Heater

When considering the purchase of a tankless water heater, one of the most crucial specifications to understand is the gallons per minute (GPM) rating. This figure represents the amount of hot water the unit can deliver in a minute and is essential for ensuring that your household's hot water...

camplux.com

 

[HawkinsHollow]

LOL

I'm on well and septic meaning that during a power failure I don't have potable water - or flush toilets unless I get buckets of water from my creek half a mile out in the back 40. Uphill both ways.

My neighbor's 40 year old septic bed failed and started backing up into the house. He had to wait 3 weeks to get it replaced meaning no showers, no dishwasher, no laundry and he had to spend $300 to get his tank pumped out every time it got full during his wait.

When your sanitary water system doesn't work 40 seconds waiting on hot water will seem trivial.

We all make our beds and we have to lay in them. No one forced you to live like that. Is there a better solution than driving 1/2 mile to get buckets of water? It's called a generator.

I don't want to lay in a bed where I have to wait 60 seconds to wash my hands in warm water.
First world problems? 100%. Do I have the tools to fix this trivial issue? I think I do.

 

[pmsmechanic]

My neighbor's 40 year old septic bed failed and started backing up into the house. He had to wait 3 weeks to get it replaced meaning no showers, no dishwasher, no laundry and he had to spend $300 to get his tank pumped out every time it got full during his wait.

Before I would pay to have my tank pumped I would set up a temporary sump pump and just pump the black water into the trees somewhere.

 

[Sigarms]

We all make our beds and we have to lay in them. No one forced you to live like that. Is there a better solution than driving 1/2 mile to get buckets of water? It's called a generator.

Golly, I looked at generators when I took a training class on them. For myself, it's not worth the investment if I only want to run a partial load because if I ran it at close to full load, I wouldn't have any propane left in my tank after a week (if power was out that long).

Instead of walking down to our creek, we generally keep a sufficient amount of water in house

Been here 20 years, seemed to get by without a generator, but that's just us.

Out of curiosity, at the master bath, on the second floor, furthest away from the mechanical room in the basement, turned on the hot water and water was warm after 2 seconds, so I can at least live with that LOL

 

[HawkinsHollow]

Out of curiosity, at the master bath, on the second floor, furthest away from the mechanical room in the basement, turned on the hot water and water was warm after 2 seconds, so I can at least live with that LOL

And that is with a tankless WITH or WITHOUT a recirc pump?

 

[WinterDeere]

I mentioned this in another thread recently, so apologies to those who already know this one. England has a bad reputation for electrical and plumbing systems, and it's well-deserved, they really love holding onto old hardware and conventions. When staying in a 1000 year old hotel in Stratford Upon Avon, I switched rooms mid-week, from one that took roughly 4 minutes to receive hot water, to another that took over 8 minutes.

That may not sound nearly as absurd as it feels, until you're the one standing there for roughly 480 seconds, waiting for hot water. Knowing how things are over there, I wasn't even alarmed when I had no hot water for the first several minutes, but did call down to the front desk at the 5 minute mark. They told me, "give it another 3 minutes, it will get there!"

Knowing how much temperature drop we see in our own house, from basement up to 3rd floor, I can't imagine how screaming-hot they must run their boilers, to get hot water delivered from the tap over that sort of time and distance.

 

[WinterDeere]

I've actually been toying with the idea of a tankless water heater for our 3rd floor (4th, if you count basement) bathroom. The prior owners installed a 40 or 50 gallon traditional electric water heater in the unheated attic space adjacent to that bathroom, and it works fine, but will eventually leak. It's also a very old house (that wing was added 1775), with vintage plaster we'd like to not ruin, and it's a massive amount of weight sitting up there.

But delivering power to it, and freeze protection, are both concerns. The tank heater conducts enough constant heat out thru the plumbing, that we've never had issues with freezing pipes, even below 0F. Delivering propane up there would be possible, as the regulator set is just outside this bathroom, albeit 50 feet below. I think the sub-panel in that room is 100 amps, but I need to check current loading to see what sort of excess capacity we have, there.

If the electric models had freeze protection, that might be the path of least resistance, but I really haven't looked into how well that works. The bathroom sat unused for most of the last 10 years, but now one of my kids is using it, so water usage up there is just 2x per day.

 

[Sigarms]

And that is with a tankless WITH or WITHOUT a recirc pump?

With of course.

Please note, I said warm water, not hot water.

My only point was that I believe a lot of people are on well and septic. When power goes out, you won't have hot anything unless you have a generator. The question then becomes how long will your generator run if running a full load if you're on LP.

 

[WinterDeere]

My only point was that I believe a lot of people are on well and septic. When power goes out, you won't have hot anything unless you have a generator. The question then becomes how long will your generator run if running a full load if you're on LP.

As one of the hold-outs with an oil-fired boiler in our basement, people ask why I don't convert to heat pump... until there's a power outage. I think it takes all of 3-4 amps at 120V, to run the boiler, circulator pump, and zone valves.

 

[Sigarms]

As one of the hold-outs with an oil-fired boiler in our basement, people ask why I don't convert to heat pump... until there's a power outage. I think it takes all of 3-4 amps at 120V, to run the boiler, circulator pump, and zone valves.

I installed a Burnham V7 oil boiler for my dad back in 92 up in Pa. When I was helping him sell the house in 2018, the cast iron heat exchanger had a pin hole leak (actually a issue with that series I found out later), I had the realtor replace it with a EFM oil boiler (price hard to beat even if I tried to do it traveling 480 miles away).

BEST heat in the world IMO comes from a boiler IMO

When my dad moved in with us in the basement, he had to keep the thermostat set to 80 degrees pretty much year round to make it feel like 72F with his old boiler in his home LOL

Deal with anyone over the age of 60 who is used to oil heat with a oil furnace, worst case, just dual fuel it with a heat pump and leave the oil furnace...

 

[ponytug]

I've actually been toying with the idea of a tankless water heater for our 3rd floor (4th, if you count basement) bathroom. The prior owners installed a 40 or 50 gallon traditional electric water heater in the unheated attic space adjacent to that bathroom, and it works fine, but will eventually leak. It's also a very old house (that wing was added 1775), with vintage plaster we'd like to not ruin, and it's a massive amount of weight sitting up there.

But delivering power to it, and freeze protection, are both concerns. The tank heater conducts enough constant heat out thru the plumbing, that we've never had issues with freezing pipes, even below 0F. Delivering propane up there would be possible, as the regulator set is just outside this bathroom, albeit 50 feet below. I think the sub-panel in that room is 100 amps, but I need to check current loading to see what sort of excess capacity we have, there.

If the electric models had freeze protection, that might be the path of least resistance, but I really haven't looked into how well that works. The bathroom sat unused for most of the last 10 years, but now one of my kids is using it, so water usage up there is just 2x per day.

For the amount of hot water usage that you describe, I would personally pull the existing 4th floor hot water heater and remove it. That just seems like an accident waiting to happen at a risk to reward ratio that seems pretty high risk. If hot water is an issue, I would add an on demand recirculating pump like the one @HawkinsHollow posted above.

It's your home, but I like vintage plaster myself. Despite being a fan, I think that it is a pain to install/reinstall in this day and age, and I would personally hate to have to do it over a water tank leak high in a house.

All the best,

Peter

 

[WinterDeere]

When my dad moved in with us in the basement, he had to keep the thermostat set to 80 degrees pretty much year round to make it feel like 72F with his old boiler in his home LOL

yes, I've noticed this. We find the same relative comfort at 70F with the baseboards going, as 76F when heating solely with wood stoves. I think it has to do with the fact that hydronic baseboard is typically routed along all exterior walls, creating a warm blanket of air that somewhat compensates for both radiation and convection cold exterior walls.

For the amount of hot water usage that you describe, I would personally pull the existing 4th floor hot water heater and remove it.

I'll have to look at that, as I know even tankless systems have a high probability of failing and leaking, at some point. It's weird that they ran both cold and hot from the basement boiler room to our 3rd floor kitchenette, but then pulled only cold up to the bathroom on the same floor. I'm not sure why, but you can imagine that getting another pipe run from the basement in the 1890's addition into the 3rd floor of the 1770's addition, is no simple feat.

For now, I have a flood sensor installed in the small pan the original installer placed under the water heater, and that sensor is tied into our home automation. If it detects any water in the pan, it will trip our motorized whole-house valve to close. That water heater, being the highest point in the system, should have no additional water pushing through it after that valve closes, so hopefully that will prevent disaster.

 

[Sigarms]

yes, I've noticed this. We find the same relative comfort at 70F with the baseboards going, as 76F when heating solely with wood stoves. I think it has to do with the fact that hydronic baseboard is typically routed along all exterior walls, creating a warm blanket of air that somewhat compensates for both radiation and convection cold exterior walls.

When I drove up to my dads house myself to go over everything that needed to be done, I got up there sometime around the colder months late at night leaving after work in NC.

The good old T-86 dial tstat was set to 62, needed to warm the place up, so I set it to 72F.

Went to bed almost right after that, and by the time I hit the bed, the bedroom was nice and warm.

Been a long time since I had been there in the colder months, and I remember laying there thinking on how I forgot how great boiler heat was.

 

[jyoutz]

Our tankless unit has a filter on it that is supposed to last two years. It catches sediments and minerals that would build up in the unit.

 

[Sigarms]

Our tankless unit has a filter on it that is supposed to last two years. It catches sediments and minerals that would build up in the unit.

Play it safe, clean the heat exchanger every year with vinegar if you're on a well system