Tankless Water Heater with a 1/2" supply line under 2 pounds of pressure?
#1
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Tankless Water Heater with a 1/2" supply line under 2 pounds of pressure?
Looking to see if it possible to get a tankless water heater installed in my house. Had a plumber come out this morning to took at the house and give me a quote.
One of the things I was concerned about is my gas supply line. It is 1/2" flexible line that travels about 45' to a manifold, and then splits off to my furnace (2-stage, 100k BTU for 2nd stage) and my gas stove. Upgrading it to a larger line would be near impossible due to it running through a finished basement.
My laymen's reading off how many BTU's you can supply under 1/2" pipe that distance makes it looks like it would be well undersized to supply a 200k BTU water heater, let alone it with my furnace on at the same time.
When I asked the plumber about that, he said that it should not be an issue, because we have a 2PSI system, so there is plenty of capacity to deliver the volume needed. He showed me where the regulator was on the manifold to step the pressure down.
His suggestion was to put the water heater about 5 feet away from the manifold, and if need be, put a 3/4" line from there to the water heater.
I also asked about the capacity of the meter outside (which is rated at 275CFH, which equates to ~281k BTU if I understand correctly). Does not appear to be sized to be able to handle if I run everything at full blast all the time, and he said it should not be a problem, and in that rare case where everything was on, it would degrade the performance of the appliances until it could get enough volume.
I am trying to get a gut feel if what I am being told is true about the 2PSI on the 1/2" line will work.
Oh, and I did ask if we would have to pull a permit, and he said it would be up to me decide that. That leads me to believe that he is thinking that this would pass inspection.
Thoughts?
One of the things I was concerned about is my gas supply line. It is 1/2" flexible line that travels about 45' to a manifold, and then splits off to my furnace (2-stage, 100k BTU for 2nd stage) and my gas stove. Upgrading it to a larger line would be near impossible due to it running through a finished basement.
My laymen's reading off how many BTU's you can supply under 1/2" pipe that distance makes it looks like it would be well undersized to supply a 200k BTU water heater, let alone it with my furnace on at the same time.
When I asked the plumber about that, he said that it should not be an issue, because we have a 2PSI system, so there is plenty of capacity to deliver the volume needed. He showed me where the regulator was on the manifold to step the pressure down.
His suggestion was to put the water heater about 5 feet away from the manifold, and if need be, put a 3/4" line from there to the water heater.
I also asked about the capacity of the meter outside (which is rated at 275CFH, which equates to ~281k BTU if I understand correctly). Does not appear to be sized to be able to handle if I run everything at full blast all the time, and he said it should not be a problem, and in that rare case where everything was on, it would degrade the performance of the appliances until it could get enough volume.
I am trying to get a gut feel if what I am being told is true about the 2PSI on the 1/2" line will work.
Oh, and I did ask if we would have to pull a permit, and he said it would be up to me decide that. That leads me to believe that he is thinking that this would pass inspection.
Thoughts?
#2
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Welcome to the forums.
I think you should get a couple more plumbers out to bid this job for you.
Not my area of expertise but I don't think this is going to work.
Hang tight, the pros will be along shortly with better info.
I think you should get a couple more plumbers out to bid this job for you.
Not my area of expertise but I don't think this is going to work.
Hang tight, the pros will be along shortly with better info.
#3
Hello and welcome..
At 45 ft you have about 285 k BTU to the manifold..
Whats the total btu of furnace and stove?
How are you heating your hot water now?
Way undersized IMO..
You need to run a dedicated line from the meter to the tankless.. PERIOD!!..
Well the meters are tested at a higher capacity and can probably run 500k btu as I was told by the gas company.
But all you need to do is call the gas company to upgrade the meter.
And you need to find a new guy/plumber. If he told you it will degrade performance, is an idiotic statement IMO. What it will do is for example is starve an appliance of gas. This can cause sooting of the burner/exchanger and/or draft issues. Then deadly CO issues in the home..
Basically you can wake up dead...
LOL. It will not pass. But you can have him install wrong, pull a permit then when it fails he will need to come back at no charge and run that new gas line and install it correctly...
Oh and why do you want a tank-less. They are not all that good you know.
It is 1/2" flexible line that travels about 45' to a manifold, and then splits off to my furnace (2-stage, 100k BTU for 2nd stage) and my gas stove.
At 45 ft you have about 285 k BTU to the manifold..
Whats the total btu of furnace and stove?
How are you heating your hot water now?
Way undersized IMO..
When I asked the plumber about that, he said that it should not be an issue, because we have a 2PSI system, so there is plenty of capacity to deliver the volume needed. He showed me where the regulator was on the manifold to step the pressure down.
I also asked about the capacity of the meter outside (which is rated at 275CFH, which equates to ~281k BTU if I understand correctly). Does not appear to be sized to be able to handle if I run everything at full blast all the time, and he said it should not be a problem, and in that rare case where everything was on, it would degrade the performance of the appliances until it could get enough volume.
But all you need to do is call the gas company to upgrade the meter.
And you need to find a new guy/plumber. If he told you it will degrade performance, is an idiotic statement IMO. What it will do is for example is starve an appliance of gas. This can cause sooting of the burner/exchanger and/or draft issues. Then deadly CO issues in the home..
Basically you can wake up dead...
Oh, and I did ask if we would have to pull a permit, and he said it would be up to me decide that. That leads me to believe that he is thinking that this would pass inspection.
Oh and why do you want a tank-less. They are not all that good you know.
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At 45 ft you have about 285 k BTU to the manifold..
Whats the total btu of furnace and stove?
How are you heating your hot water now?
Whats the total btu of furnace and stove?
How are you heating your hot water now?
Stove is ~55k BTU will all the burners running
Hot water is now being made via a 12-year-old gas AO Smith water heater.
And you need to find a new guy/plumber. If he told you it will degrade performance, is an idiotic statement IMO. What it will do is for example is starve an appliance of gas. This can cause sooting of the burner/exchanger and/or draft issues. Then deadly CO issues in the home..
LOL. It will not pass. But you can have him install wrong, pull a permit then when it fails he will need to come back at no charge and run that new gas line and install it correctly...
Oh and why do you want a tank-less. They are not all that good you know.
Oh and why do you want a tank-less. They are not all that good you know.
As for why? Just checking out my options before my old water heather dies. It is currently too small for my house, and the plumber also offered up a 2 50 gal tank solution, or a 75 gal tank solution.
#5
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I have a 40 gallon gas water heater and have never run out of hot water even if the dishwasher, washing machine and two showers are going at the same time.
What do you have now and what is taxing the capacity?
What do you have now and what is taxing the capacity?
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50 gallon, but after 12 years, that will be reduced off course.
What causes it to fall short?
2 pre-teens that take long showers, 6 loads of laundry a day, and a huge soaker tub!
The amount of times that hot water is gone not often, but is by about the 3rd shower in a row after the pool, etc.
Not a huge issue right now, and as said before, trying to get my ducks in a row when (not if) my current one goes.
What causes it to fall short?
2 pre-teens that take long showers, 6 loads of laundry a day, and a huge soaker tub!
The amount of times that hot water is gone not often, but is by about the 3rd shower in a row after the pool, etc.
Not a huge issue right now, and as said before, trying to get my ducks in a row when (not if) my current one goes.
#7
Furnace is 100kBTU
Stove is ~55k BTU will all the burners running
Stove is ~55k BTU will all the burners running
Say 100k furnace
90 k stove
40k HWH
Thats 230k btu.. You have 285k btu to manifold. Only 55k btu left. You cant add a 200K appliance to the manifold. You need to run a dedicated line to the meter for the tankless.
Now since you have 55k left on the manifold, you can install two 40's or 50's or one 75 gal. The 75 gallons are 75K btu. The two 40's or 50;s will be 80K combined.
Atmospheric vent? Where does the heater vent now?
#9
Current hot water heater vents through a flu/chimney up to the roof.
#10
The cheapest route will be two 40 gallon ao smith heaters.
They are $360 each. You can get them at your local Ferguson dealer. They sell to the public..
Then add labor of proper piping, venting, gas work...ect.. Should be under $2k..
If your going the tank-less route A noritz 199k btu unit runs $1500. To hook these up correctly you need a buffer tank and a recirc pump. Unually a 20 gal electric heater is uses as a buffer tank. (electric not hooked up)
This prevents cold slugs, and the sandwich effect you get with tankless. Those heaters are $400.
The pump UP10-16BU ATLC grunfos with build in aquastat runs $200
So $2100 without labor.
Read here about recirc line/ buffer tanks. There are many ways to do it.
This link is for info only. None of the diagrams here would be how I would hook it up.
http://www.finehomebuilding.com/pdf/021192082.pdf
Also don't expect to run multiple appliances and fixtures with a tank-less. Its based on how cold the water is coming into the home. Maybe 5 gallons a minute max, unless you live in warm climates..
You need to run a return line but dont know how your house is set up..
They are $360 each. You can get them at your local Ferguson dealer. They sell to the public..
Then add labor of proper piping, venting, gas work...ect.. Should be under $2k..
If your going the tank-less route A noritz 199k btu unit runs $1500. To hook these up correctly you need a buffer tank and a recirc pump. Unually a 20 gal electric heater is uses as a buffer tank. (electric not hooked up)
This prevents cold slugs, and the sandwich effect you get with tankless. Those heaters are $400.
The pump UP10-16BU ATLC grunfos with build in aquastat runs $200
So $2100 without labor.
Read here about recirc line/ buffer tanks. There are many ways to do it.
This link is for info only. None of the diagrams here would be how I would hook it up.
http://www.finehomebuilding.com/pdf/021192082.pdf
Also don't expect to run multiple appliances and fixtures with a tank-less. Its based on how cold the water is coming into the home. Maybe 5 gallons a minute max, unless you live in warm climates..
You need to run a return line but dont know how your house is set up..
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Thanks...great information. I appreciate it.
I do know we would have to vent differently for a tankless, and that will be straightforward given the layout of my basement.
I am leaning towards the 2-50 gal tank solution. Any suggestion on a specific model with a high recovery rate?
I do know we would have to vent differently for a tankless, and that will be straightforward given the layout of my basement.
I am leaning towards the 2-50 gal tank solution. Any suggestion on a specific model with a high recovery rate?
#12
I would go 50 gallon power vent. I put one in for a family member, 4500 sq. ft. house with 5 people. He has never had a hot water issue.
I have installed many tank less and have had way to many issues with them. They are money makers for the plumbing company and that's it. I would say 75% of the ones we did the homeowner needed a gas meter upgrade. I believe it was around 700 back in 2008. I did a tank less for my parents because my father insisted. I remind him every time it goes down that he insisted. The last issue had it offline for 10 days.
You also have to flush the tank less every year or the warranty is void.
I have installed many tank less and have had way to many issues with them. They are money makers for the plumbing company and that's it. I would say 75% of the ones we did the homeowner needed a gas meter upgrade. I believe it was around 700 back in 2008. I did a tank less for my parents because my father insisted. I remind him every time it goes down that he insisted. The last issue had it offline for 10 days.
You also have to flush the tank less every year or the warranty is void.