Going to replace hot water tank. Need some advice

[lzicc]

A big reason I want to go with tankless is free up some room in my utility room or I would consider a tank one. Plus if I go with a tank one, I have to get a power vent so I can vent it out the side and a 40 gallon power vent is a little over $800, so I may as well spend a few hundred more and get the tankless for that price.

 

[buickanddeere]

Power is cheapest from 7:00PM to 7:00AM weekdays and all weekend . Tank does not reheat after the kid痴 morning showers until 7:00PM. Don稚 seem to run out of hot water .

 

[zzvyb6]

My mistake. I have 1" copper water lines in the house and 3/4" in and out of the Rheem. The neckdown is about 2' away. This was where the old 50 gallon take hooked up. It sure does free up a lot of space. BTW: This unit has ports for cleaning and flushing. They have a kit to do the back flush. Close the valves, attach the solution bottle and let it flow. No problems with using well water. The only issue I'm curious about are the sink faucets. Single handle deals which are usually in the center position. Using a sink for a few seconds (as in: add water to instant oatmeal) can start the unit. Leaving the handle in the cold position does not kick the unit. Something to further investigate.

 

[lzicc]

Thanks for the pictures. It looks like it uses - 2" PVC for the vent and the fresh air. Does your fresh air go to the outside? For the hot water coming out of the unit that I install will be a least a few feet until I have to reduce to 1/2" to connect to my 1/2" line where my current water tank is.

 

[lzicc]

I am going to purchase and install the valve set. From the hot water side, I was going to run 3/4" pex then reduce to 1/2" to connect to my house hot side copper lines. I wouldn't think pex would be an issue that close to the unit. The hot water should not come out hotter than 120 degree I think.

 

[lzicc]

I called my gas company. I have a 7" water column supplying my gas. Not sure what that means, but as long as i don't exceed 400,000 BTU at once, I will have enough volume to run the tankless water heater. I started looking at the Rinnai at Lowes. It is only 7.5 GPM instead of 9.5 which the RHeem is. I'm thinking 9.5 may be overkill for my house. This would save me about $300 on the water heater purchase and it would require less BTU's which isn't an issue. I just want to make sure I oversize my water needs by a little bit. I called Rinnai and they said a 6.5 gpm unit would suffice, so going up to the 7.5 would give me a little edge.

 

[Cord]

I have a hybrid tankless of a comparable size in my home and I'm very happy with it. Have had three fixtures running at once (shower, tub and lav) and have never seen a short fall of hot water. I believe if you had a high flow tub filler you cold max it out if you had 55 degree ground water. These units push a lot of btu so you need to watch the gas pipe and exhaust pipe sizes. I ended up having to run 1" pipe to the heater and the vent pipes needed to be 3". You can get by with smaller pipes, but it depends on the number of bends and the length of the runs. The literature will get into that. The only other comment that I have is to look at a hybrid unit. These have a small 3-4 gallon tank inside of them. This tank helps to eliminate the cold water sandwich that tankless units suffer from.

 

[buickanddeere]

Go big or always wish that you had .

 

[zzvyb6]

Thanks for the pictures. It looks like it uses - 2" PVC for the vent and the fresh air. Does your fresh air go to the outside? For the hot water coming out of the unit that I install will be a least a few feet until I have to reduce to 1/2" to connect to my 1/2" line where my current water tank is.

Yes air in and exhaust out are outside (by code). I have two house furnaces that are high efficiency with outside air and exhaust vents. There is a code requirement for spacing from one system to another. (30" ??) A bit crowded out there. And you need to pay attention to possible frost accumulation. Neighbors exhausted underneath their deck and the inlet frosted shut. Pressure sensors shut down the furnace AND the tank. Not a popular fix and repair on the coldest day of the year.

BTW: There is a condensate drain line that needs to be plumbed to somewhere, too.

 

[lzicc]

I'm getting the area prepared. I am going to go with the Rheem. I put a 1" x 3/4" tee from the main line in the utility room for gas supply. The heater will be mounted in the basement utility room. The ceiling is finished, so I cut a 1' x 16" hole in the ceiling drywall so I have some room to work for the vent. The vent run will be 5'. I am going to run 2 pipes, one for the vent and one for the fresh air. Since the distance is only 5' for the vent, I should be able to go with 2" PVC for the vent.

zzvyb6, what size is your vent? I don't have the unit yet to look at, but I would like to run the vent pipe to the outside and get that part out of the way.