Tankless water heaters

[barmstrong2]

Well, it looks like the tankless idea is out. Turns out that I'd have to replace the supply lines all the way from the tank in order to support the BTUs.

I see you've found the solution to the original topic, but, I wanted to bring this piece back into discussion. If you ever want to add another gas burning appliance, it might become relevant again.
Rather than replace the supply lines, you could use the existing supply lines and convert the system to a 2 lb delivery system. Each appliance requires a regulator and the regulator at the tank is replaced. This is a common procedure and eliminated the need for replacing/increasing supply lines or, with new installations, reduces cost by eliminating the need for large pipe sizes.

 

[KD0AXS]

I see you've found the solution to the original topic, but, I wanted to bring this piece back into discussion. If you ever want to add another gas burning appliance, it might become relevant again.
Rather than replace the supply lines, you could use the existing supply lines and convert the system to a 2 lb delivery system. Each appliance requires a regulator and the regulator at the tank is replaced. This is a common procedure and eliminated the need for replacing/increasing supply lines or, with new installations, reduces cost by eliminating the need for large pipe sizes.

We have a 3/8" line @10 PSI from the tank to the house, then a regulator on the outside of the house drops it to 2 PSI. Then there's a 1/2" line @ 2 PSI down to the basement, where there's a regulator that drops the pressure to the standard 11" WC before splitting to each appliance.

According to the charts I was looking at, the tankless water heater alone would have put both the 10 PSI line and the 2 PSI line right at max capacity, with no capacity left for any additional appliances to be running at the same time.

 

[barmstrong2]

We have a 3/8" line @10 PSI from the tank to the house, then a regulator on the outside of the house drops it to 2 PSI. Then there's a 1/2" line @ 2 PSI down to the basement, where there's a regulator that drops the pressure to the standard 11" WC before splitting to each appliance.

According to the charts I was looking at, the tankless water heater alone would have put both the 10 PSI line and the 2 PSI line right at max capacity, with no capacity left for any additional appliances to be running at the same time.

I see. It always causes me to wonder why a technician would install a system with no room to grow.

 

[Bret Chase]

Tankless water heaters are a scam. The idea is that you save the waste from keeping a tank of water hot all the time. But do the computation of how much energy is wasted - quite simple, just the tank's surface area, times the temperature differential (between the hot water and the outside air), divided by the R-value of the tank insulation (16 for a good modern high-efficiency unit). You get a pretty small number. This waste is dwarfed by the losses from the hot water that is left in the pipes after you turn on the hot-water faucet, use it, and then turn it off. Perhaps if you have a tankless unit in every bathroom and in the kitchen, you'd reduce those losses. But that would cost so much money that it'd be better spent on a photovoltaic solar installation. Also, tankless units are much more failure prone, and parts are expensive and hard to get (the guy who helps me with this stuff says that some companies won't even sell him parts, because he hasn't been to their factory school).

My brother has has an on demand hot water LP heater that was put in when he built his house (2005).... he hated it to the point where he went and put in a regular old electric DHW a few years ago....

 

[Bret Chase]

OP, one thing you could do to get some extra "apparent" capacity from a standard 50 Gal unit is to run it at a higher temp and then use an external tempering valve to mix cold water with the WH output to get it to usable temps.
This will result in some loss of overall efficiency due to heat loss with from a higher temp differential between in tank and outside the tank.

This is actually quite common in commercial installations... run the super stores up to boiler temp (180)... and temper the DHW down to 120... it can be a godsend in tight boiler rooms, as you can "get away" with a smaller tank...

 

[Bret Chase]

I see. It always causes me to wonder why a technician would install a system with no room to grow.

I have often wondered why gas companies do what they do... and the lazy ass installs that they charge top $$ for.

 

[barmstrong2]

I have often wondered why gas companies do what they do... and the lazy ass installs that they charge top $$ for.

That's why independent gas contractors, like me, are able to retain customers year after year.