Tankless water heater recommendation

Old 04-10-11, 06:50 PM
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Tankless water heater recommendation

My kitchen sink and dishwasher are about 100' of pipe from my 50 gallon LPG water heater. It can take quite a while to get hot water to them. I've got good attic space and access above the kitchen, so I'm considering adding a small tankless LPG water heater above the kitchen that would make it about 15' from the tankless to the sink/DW. The LPG trunk line enters the house about 10' feet away, but a Tee would have to be added to the trunk line to tie in the tankless unit. I still need to check the trunk line capacity to make sure it can handle the additional load. Venting would be straight up, about three feet to get thru the roof.

Comments? Good/bad idea? Suggestions on a particular brand/model? I'm aware of the hot water recirculation pumps as an alternative to adding a tankless.

Old 04-10-11, 07:20 PM
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I have a somewhat similar problem although not as bad as 100 feet of pipe. I was thinking about installing an electric tankless "booster" until I found out how much it would cost. I think you will find that installing the gas tankless will be even more expensive than my idea of the electric.

My "fall back" idea is to install a 1/2 inch copper recirculating line and bronze pump. I plan on using a current-operated switch through a low-voltage system to operate the pump continuously while the dishwasher is running since I have several of these switches in my junk box. I will also install momentary-contact switches at all the sinks in the house to start the pump (with a timed shut-off) to get near-instant hot water. Even if I had to buy all the parts new I think it will be less expensive than a second water heater, either electric or gas.
Old 04-10-11, 09:00 PM
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I'm aware of the hot water recirculation pumps as an alternative to adding a tankless.
They make two retro fit types that I know of.

1. Pump goes by HWH and check valve under sink. These pumps have a timer to set the on and off. Since these waste energy you might want to set the timer for every 15 minute to come on for a few minutes.

2. They make the pump for under the sink. You need electric there. These are timer based also but you also have a button you push to get HW. So like when you get up in the morning push the button.

With LP its a fine line since running these pumps constantly will increase your LP usage. You need to weigh your options.

Tankless LP you need alot more BTU to run and probably would not be able to tap the line. This I feel will be a waste, since the high cost. You will still have to wait for HW.

The DW should have a accu temp setting where it heats the water to 140F by the coil inside. I use this setting on my own DW. I do run the kitchen sink befor the initial fill though. It helps.

As far as the kitchen sink(and DW) possibly a point of use will be better.

This is just one brand. Comes in 6 gallon.

Ariston Ariston Mini-Tank Electric Point of Use Water Heater - GL6 Plus at The Home Depot

I would stay away from the LP tankless, but thats just my experience.

Mike NJ

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